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CC - Storm DrainagePrepared For: Brighton Development, Inc. & ACHD Ian E N G I N E E R I N G Pollard Subdivision No. 1 Meridian, Idaho Storm Drainage Report Digitally signed by Lachlin C Kinsella, P.E Date: 2022.07.19 18:45:18-06'00' NAL fNc LENSF 16860 s� 7/19/22 0 9r4' 0 F 0, lC� C. Y Prepared By: Lachlin Kinsella, P.E. Project Manager KM Engineering, LLP 5725 North Discovery Way Boise, ID 83713 208.639.6939 Ikinsella@kmengllp.com July 2022 Project No: 21-240 TABLE OF CONTENTS Introduction -------------------------------------------I Project Description ---------------------------------------.l SiteDescription ............................................................................................................................... 1 Scopeand Methods ........................................................................................................................ 1 Existing Drainage Conditions .......................................................................................................... 1 Proposed Drainage Conditions and Analysis .................................................................................. 1 SeepageBeds .................................................................................................................................. 2 SeepageBeds .................................................................................................................................. 2 Summary......................................................................................................................................... 3 APPENDICES Appendix A - Figures Figure l -Vicinity Map Figure 3-Post-Development Drainage Map Figure 3 - Storm Water Improvement Plans Appendix B-TabUes Table Peak Flow Rates and Runoff Volumes Appendix C-CaUcuUBtions Post -Development 25-vearCalculations Post -Development 10O-yearCalculations Seepage Bed Calculations Appendix D-GeotechnicaUE'neeKing Report Geotechnica| Report (K4T|, 8/31/I6) INTRODUCTION The purpose of this report is to show that the storm drainage facilities for the proposed Pollard Subdivision No. 1 (Project) are designed to meet Ada County Highway District (ACHD) and the water quality requirements of the Idaho Department of Environmental Quality (DEQ). This report has been prepared at the request of the developer, Brighton Development, Inc. PROJECT DESCRIPTION The Project consists of the first phase of the subdivision that includes proposed improvements to the site roadways, sidewalks, lot grading, and site utilities. Three of the streets will be public and four of the streets will be privately owned and maintained per the construction plans. SITE DESCRIPTION The Project site is located north of W. Chinden Blvd. and east of Highway 16 in Meridian, Idaho. See Appendix A, Figure 1 for a vicinity map of the project. The proposed Project area is 51.56 acres. SCOPE AND METHODS The stormwater system for the Project has been designed per the 2017 ACHD Stormwater Policy. The Rational Method is the standard method for small catchments and was used to calculate post -development peak runoff rates and runoff volumes. The Rational Method provided in the ACHD calculation sheets was used to calculate the storm water volumes and flow rates for this project (see Appendix C - Calculations). Flow rates and storm volumes were established for each basin for the 25-year and 100-year storms. Refer to Appendix B, Table 1 - Peak Flow Rates and Runoff Volumes, for a summary of flow rates and runoff volumes. Calculations for the seepage beds were completed to verify capacity. EXISTING DRAINAGE CONDITIONS The pre -project watershed consists of primarily agricultural land and is currently irrigated through open channels. The flow path for the existing drainage basin involves overland sheet flow from east to west with irrigation wastewater being collected through open channels and routed to a nearby gravity irrigation ditch. There are no existing storm drainage facilities in place to reduce the peak runoff volumes prior to discharging into the ditch. PROPOSED DRAINAGE CONDITIONS AND ANALYSIS The proposed drainage system improvements consist of roadway inlets and gutters, diversion boxes, seepage beds, infiltration basins, and borrow ditches. The post -development site was broken into thirty-one (31) basins as shown in Appendix A, Figure 2 - Post -Development Drainage Map. For land use type and runoff coefficients (0.1— open space, .95 — impervious, 0.40 — lots) for each basin, refer to ACHD calculations 1 in Appendix C. Each basin was delineated according to the tributary area draining to each drainage structure or facility such as gutter, catch basin inlet, etc. For individual sub -basin peak flow calculations, in addition to combined sub -basin peak flows used for downstream facility sizing and analysis, see Table 1 (Peak Flow Rates and Runoff Volumes). The proposed drainage basins include the proposed roadways, sidewalks and planter strips. The time of concentration is calculated using shallow concentrated flow for the road curb and gutters. The stormwater from the roads is conveyed using the curb and gutter to catch basins and is then retained on site through seepage beds. INLET AND GUTTER CAPACITIES The catch basin inlets should be built per the details shown on the civil construction plans. There is a total of thirty-one (31) inlets, one for each drainage basin where storm water is routed to a seepage bed. Based on our calculations, all inlets will require a single sump grate inlet to intercept the flows. The gutter capacity of the proposed roadways was verified to ensure that overtopping of the curb would not occur in the 25-year and 100-year storm event. SEEPAGE BED The Project includes sixteen (16) seepage beds (SB #1-#16) that should be built per the details shown on the civil construction plans. Seepage beds #1-10 will be dedicated to ACHD and seepage beds #11-16 will be private. Based on our calculations, the seepage beds are adequately sized to ensure that no ponding occurs on the surface and that the volumes required to retain the 100-year storm event are met. The invert elevation of the seepage bed is set above the estimated high groundwater level based on the "Geotechnical Engineering Report" prepared by MTI, dated August 31, 2016. Once the size of the seepage bed was calculated, the time necessary for 90% of the 100- year storm events to be infiltrated into the ground was calculated at less than 48 hours. The Geotechnical Engineering Report prepared by MTI recommends an infiltration rate of 8 inch/hour, which was used in the design of the seepage beds. The calculations included with this report show the volumes that are required to be retained for the 100-year storm and the drain time through the bottom of the seepage beds, refer to Appendix B — Tables and Appendix C — Seepage Bed Calculations. SUMMARY This report determines that the Project storm water design sizing and analysis conforms to ACHD and storm water design criteria. The post -development storm water runoff for the entire roadway, sidewalks, and planter strips should be completely retained onsite through the proposed seepage beds. PJ APPENDIX A - FIGURES VICINITY MAP NO SCALE 0 2000 4000 6000 mmmmmmF- 64n Plan Scale: 1" = 2000' E N G I N E E R I N G 5725 NORTH DISCOVERY WAY PHONE (2 8)639-6939 POLLARD SUBDIVISION No. 1 kmengllp.com MERIDIAN, IDAHO DATE: JULY2022 PROJECT: 21-240 SHEET: VICINITY MAP 1 OF 1 DRAINAGE LEGEND DESIGN POINTS Q A BASIN DESIGNATION 1. INLET #1 2. INLET #2 0 100 200 300 2.5 AREA IN ACRES 3. INLET #3 Plan Scale: 1"= 100' 4. INLET #4 DESIGN POINT 5. INLET #5 # 6. INLET #6 EXISTING GRADE CONTOUR 7. INLET #7 8. INLET #8 9. INLET #9 10. INLET #10 11. INLET #11 FINISHED GRADE CONTOUR 12. INLET #12 -2470 �- 13. INLET #13 14. INLET #14 15. INLET #15 i I 16. INLET #16 / 17. INLET #17 18. INLET #18 / 19. INLET #19 4 � _EP EP - EP - - - EP E _EP - - -EP - - Eis �P-��P - - - EP- - - -EEP- - - 2P - - E1- - � EP-c�P -�P -�I 21. INLET #21 0 d3 P EP EP EP - EP- P EP - �EP� P EP E ♦G - EP EP • - f E EP _'I-� 23. INLET #23 - - _ J 24. INLET #24 25.INLET #25 26. INLET #26 z I / 27. INLET #27 28.INLET #28 29.INLET #29 30.INLET #30 31. INLET #31 N I / / - - - / - - - - 32.SEEPAGE BED #1 O 33.SEEPAGE BED #2 _ / I 34.SEEPAGE BED #3 L I{ (- 35.SEEPAGE BED #4 > / 36. SEEPAGE BED #5 ~ z 37.SEEPAGE BED #6 �I 38.SEEPAGE BED #7 I / 39. SEEPAGE BED #8 / 40.SEEPAGE BED #9 5� M� M� M�0 F -1�' M° / 41. SEEPAGE BED #10 f ti 25 r 1 3 / ti� ryh N 5 �� / 7 /) 0� tiM tiM�p / 42. SEEPAGE BED #1 1 B-1 43.SEEPAGE BED #12 a 2$ 49 0.46 _ C-t 2538 2538 0.63 / ti�k1 / 45. SEEPAGE BED #14 W. WA DR. 0.22 _ 3. SEEPAGE BED #15 A-2 2-- .-25414 C_2 I 1 I I~ 47,SEEPAGE BED #16 z 00 0.50 00.16 a LLJ 2 32 �`' z 4 33 / / / Is, ;I / �s Y 6 34 / 8 35 E-1 9 _ 0.16 5a1 0.21 \ �j \ � \ 2 \ \ \ � �9 S� � u 0 0.18 2 \ F \ \ \ 1 '2s33 S32 2 o S \ M-2 M_1 F-2 F-1 \ \ \ \ `�d, \ \ � 46 0.26 0.25 \ ? 2s 2 2S a 40 \253 ` ?S \ \ 37 �Mr 2 SCR SS\ Sys \2 \2S3 2SS \ JS \ 10 z 17 \ S`� o �O 44 534 \ SSs SSS \ \ \ I Q �I 2S2jy 252�` \ 25 1 24 J 2 \ \ r 1 12 26 uJ \ \ 'a l \ \ \ \ \ N-, 1 1 \ 28 �� o-, \ \ \ co I - - O Q 0.37 W. LITTLE RAVEN LN. a _ 0.55 W. LITTLE RAVEN LN. \ \ a d S --- -- N-2---------- -- --- -- - - --- -\ IN z • z I I zI 0\ Q < LJ N 45 29 46 P-1I0 _2538 2528 0.25 0.24 M°j 41 \2s \ L-2 L-t -2530, 14 ` I 13 \ \ \ \ 0.30 �y CoQ W_ 0.26 0.25 - -----\-2-53-2 I D Q 2526_ -----V) 47 2532 J-1 J-2 2538_ = 0.24252a22 ?536 - - - - - - - ^ QC Lu Cd> 3 � / 2 ,yp �2529- \ \ \ N� \ 3S \ J Lu 5 \ \� 21 A / 43 39 1 IIJ L S33\ \ \ \ x X. X x ` x x - N f K-2 / J �\ 16 1 II 5 I nI Jim 04 2S \ \ 0.35 W. SAINT CROIX LN. K-t 2g29 I I z - - _ - _- _- H-2 H-1 / � 20 = 0.19 _ _ _ = _ -- -- - - -- 0.52 0.44 / \ r . FI_ di - o- EP-EP-EP-EP EP EP EP EP EP F- EP EP EP EP EP W. CHINDEN BLVD. - EP EP EP EP EP -FA EP EP EP EP EP E EP EP EP EP EP EP EP �- EP t,Q EP EP P EP EP EP EP EP EP EP EP f w � I 1 9 I lul EP EP E �- ENGINEERING 5725 NORTH DISCOVERY WAY BOISE, IDAHO 83713 PHONE (208) 639-6939 kmengllp.com DESIGN BY: LCK DRAWN BY: LCK CHECKED BY: LCK DATE: J U LY PROJECT: 21-240 SHEET NO. 1 OF 1 9 8^w ' 8w e" 4.3' 12" ADS N-12 413 - ® 0.46% "Ps - 9 e< \YIOC�HD STORM DRAIN MENT8" ADS N-12 HP B 0.00% INLET #2 ec_j ACHD SD-601, TYPE I RIM:2530.00 SUMP:2525.75 6 I INV IN:2526.75 12" (N) INV OUT:2526.75 12" (S) Q25=0.70 I� Q100=0.98 SGT #1 10 RIM:2530.56 (W) RIM:2530.59 (E) INV IN:2526.73 12" (N) _ INV OUT:2525.88 18' (E) INLET BAFFLE:2526.05 OUTLET BAFFLE:2526.63 Q25=1.39 Q100=1.94 I� I I I I I� I I I I rs 1 35.0' 18" ADS N-12 HP ® 0.00% I JI-�_ ACHD STORM DRAIN EASEMENT INLET #18 -SEDIMENT BOX #9 11 I� INLET RIM:2527.58 MANHOLE RIM:2528.12 INV OUT:2521.77 18" (N) a INLET BAFFLE:2521.94 rr OUTLET BAFFLE:2522.52 1 Q Ic% Q25=0.37 Q100=0.52 rl 9 INLET #18 z ACHD SD-601, TYPE I RIM:2527.30 _ SUMP:2523.18 1 INV OUT:2524.18 12" (E) Q25=0.42 - Q100=0.59 37.5' 12" ADS N-12 HP 1i ® 2.48% INLET #19 - SEDIMENT BOX #10 11 INLET RIM:2527.30 MANHOLE RIM:2527.82 m I INV OUT:2522.40 18" (S) - INLET BAFFLE:2522.57 OUTLET BAFFLE:2523.15 Q25=0.55 (INLET) 4 Q100-0.76 (INLET) rn Q25=0.97 (SEDIMENT BOX) I� Q100=1.35 (SEDIMENT BOX) A 78.0' 18" ADS N-12 HP II ® 0.00% i I I d ACHD STORM DRAIN I� EASEMENT INLET #1 ACHD SD-601, TYPE I RIM:2530.00 S U M P:2525.89 INV OUT:2526.89 12" (S) Q25=0.69 Q 100=0.96 33.5' 12" ADS N-12 HP ® 0.42% 8"s 8"s 8"s - 4"PS 4"PS 4"PS INLET #21 ACHD SD-601, TYPE I RIM:2527.89 SUMP:2523.66 INV IN:2524.66 12" (S)� INV OUT:2524.66 12" (N) Q25=0.46 Q100=0.64_ 28.5' 12" ADS N-12 HP_ 0.42% PI 6 PI 6 PI - INLET #20 ACHD SD-601, TYPE I RIM:2527.89 SUMP:2523.78 -INV OUT:2524.78 12" (N) _ Q25=0.33 Q100=0.47 SHEET NOTES A. SEE SHEET C1.1 FOR GENERAL, ACHD, AND UTILITY ASS\ONAL f,1,c/ NOTES. ENSe G 0 so too is® a� P B. SEE SHEETS C4.2 AND C4.2 FOR STORM WATER DETAILS. INLET #3 Plan Scale: 1" = 17�' 860 ACHD SD-601, TYPE I C. GROUNDWATER ELEVATIONS ARE EXPECTED TO REMAIN 7/19/22 RIM:2532.53 AT OR BELOW 13 FEET FROM EXISTING GROUND SURFACE. `!} �� Q - - NV OUT:2529.42 12" (S) THE TEST PIT LOGS, f-SUMP:2528.42 THE DESIGN INFILTRATION T WHICH SHOW POORLYE IS 8 GRADED BASED ON � GRADED �,5, lF OF r , Q25=0.64 GRAVEL AT THE APPROXIMATE BOTTOM DEPTH OF THE </N 1w Q100=0.89 PROPOSED SEEPAGE BEDS. FOR ADDITIONAL INFORMATION REFER TO THE GEOTECHNICAL ENGINEERING REPORT 9 33.5' 12" ADS N-12 HP "POLLARD LANE REALIGNMENT - POLLARD LANE & ® 0.42% CHINDEN BOULEVARD" PREPARED BY MTI, DATED AUGUST - "PL - - "PL - -LPL - - 1i"PL - - FiPL - - FiPL - - fiFl- - - fiPl- - - 6:PI- - - fiPl - - - 6:PJ - - 6" 'PI-63J - - -631 - - -631 - - LPL - - P1 31, 2016. - - -6"P1 - - "2L - - -6"PL - - D. PROVIDE WATER -TIGHT SEALS AT PIPING ENTRANCES/EXITS FOR CATCH BASINS, DIVERSION BOXES, ew ew 6w E 8'w a"w a"w s'w sw e' e'w zw z'w zw 12'w 1z'w 12'w 1z"w 12'w 12"w 2'w AND MANHOLES. a^s a"s a"s 8^s W. WAVRTON DR. s 8'S 8"s 8's 8"S 8"s4.3' 12" ADS N-12 HP m ® 0.46% E. ALL STORM PIPE WITHIN ROW SHALL BE C900 WHERE -4"PS 4"Ps 'IS4"PS a"Ps 4"Ps a"Ps 4'Ps a"Ps 4"Ps --4"PO4 S 4"PS 4"PS 4"Ps 4"Ps 4"Ps 4"Ps 4"Ps - 4"Ps 4"Ps 4"PsCOVER OVER PIPE IS LESS THAN 2 FEET. OUTSIDE OF w f ROW OR WHERE COVER IS GREATER THAN 2 FEET THE a >� STORM PIPE SHALL BE ADS N-12 HP PIPE OR N m - - - - - - - - - - - - - - - - - - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ APPROVED EQUAL. PLOWABLE FILL SHALL BE USED WHEN L 9 LESS THAN 5-FEET OF SEPARATION BETWEEN STRUCTURES. L - J 2 ACHD STORM DRAIN EASEMENT F. ALL DRAINAGE STRUCTURES SHALL BE PER ISPWC STANDARDS AND THE ACHD SUPPLEMENTS TO THE ISPWC. 1 1 63.0' 18" ADS N-12 HP STORM DRAIN STRUCTURES SHALL HAVE HS-25 TRAFFIC ® 0.00% RATED LIDS UNLESS OTHERWISE SPECIFIED. INLET #4 m ACHD SD-601, TYPE I G. THE CONTRACTOR SHALL COMPLY WITH ALL THE 1 RIM:2532.53 REQUIREMENTS FOR STORM WATER DISCHARGE Ln Z SUMP:2528.28 ASSOCIATED WITH CONSTRUCTION ACTIVITY. THIS INCLUDES z IMPLEMENTING THE BMP'S RECOMMENDED IN THE SWPP INV IN:2529.28 12" (N) N INV OUT:2529.28 12" (S) PLAN PREPARED FOR THIS SITE, REGULAR SITE > 2 o" Q25=0.60 INSPECTIONS, DOCUMENTATION OF MODIFICATIONS TO THE w F Q100=0.84 SWPPP AND OTHER REQUIREMENTS AS SET FORTH IN - THE NPDES GENERAL PERMIT. SGT #2 10 H. ALL CHANGES REQUIRE APPROVAL BY THE DESIGN I RIM:2533.10 (W) ENGINEER AND ACHD. 1 RIM:2533.12 (E) INV IN:2529.26 12" (N) I. THE CONTRACTOR SHALL PROVIDE AND INSTALL STORM INV OUT:2528.41 18' (E) DRAIN MONUMENTS TO IDENTIFY ALL STORM DRAIN INLET BAFFLE:2528.58 MANHOLES, SEDIMENT BOXES, DROP INLETS, AND OTHER I OUTLET BAFFLE:2529.16 BLOCK 2 PIPE JUNCTIONS OR TERMINUSES IN ACCORDANCE WITH W_- I Q25-1.24 SECTION 8018 OF THE ACHD DEVELOPMENT POLICY 8. Q100=1.73 MANUAL AND ISPWC SD-623. _INLET #25 J. FOR UTILITY CROSSINGS AT SEEPAGE BED LOCATIONS, o ACHD SD-601, TYPE I O z THE CONTRACTOR SHALL CONFORM TO THE STANDARDS Z :9 RIM:2530.68 � SET BY THE CITY OF MERIDIAN AND SECTION 8200 OF SUMP:2526.45 THE ACHD STORMWATER GUIDELINES. > INV IN:2527.45 12" (E) INV OUT:2527.45 12" (W) K. THE STORM WATER DESIGN IS BASED ON SECTIONS 8000 1 m Q25=0.37 AND 8200 OF THE 2017 ACHD POLICY MANUAL. : Q100=0.51 `# z 2 0!42% ADS N-12 HP KEYNOTES 38.0' 18" ADS N-12 HP INLET #24 9 I I I f I ACHD SD-601, TYPE 1 1. SB #1 SEE SEEPAGE BED (PUBLIC). SEE DETAIL #1, ® 0.00% d RIM:2530.68 SECTION A -A ON SHEET C4.2 (65'L x 13'W x 8'D) S U M P:2526.57 10 SGT #13 INV OUT:2527.57 12" (W) 2. SB #2 SEE SEEPAGE BED (PUBLIC). SEE DETAIL #1, RIM:2531.26 (S) I Q25-0.34 SECTION A -A ON SHEET C4.2 (58'L x 13'W x 8'D) RM:2531.28 (N) 7 Q100=0.48 INV IN:2527.43 (E) I INLET #26 3. SB #9 SEE SEEPAGE BED (PUBLIC. SEE DETAIL #1, INV OUT:2526.58 (N) ACHD SD-601, TYPE I _ _ SECTION B-B ON SHEET C4.2 (30 L x 8'W x 7.5'D) N INLET BAFFLE:2526.75 RIM:2530.72 f , z OUTLET BAFFLE:2527.33 I SUMP:2526.62 4. SB #10 SEE SEEPAGE BED (PUBLIC). SEE DETAIL #1, Q25=0.71 INV OUT:2527.62 12" (S) I I SECTION B-B ON SHEET C4.2 (73'L x 8'W x 8'D) Q Q100=0.99 �{ f Q25=0.49 1 r-I J 4.3' 12" ADS N-12 HP- - -�,¢ L_ - - Q100=0.68- - - - - - - - - _ m 5. SB #11 SEE SEEPAGE BED (PRIVATE). SEE DETAIL #1, 0.47% 28.5' 12" ADS N-12 HP - - - - - SECTION A -A ON SHEET C4.2 (371 x 13'W x 8'D) �•w " ' 0_0.22% _ _'w 8"w 8"w 8'w 8"w 8•w 8'w e'w e'v z z 5 r J W. LITTLE RAVEN LN. - - - - - - - - - - - - - 6. SB 12 SEE SEEPAGE BED PRIVATE SEE DETAIL 1 Z z L T � - 4.3' 12" ADS N-12 HP------------- # (PRIVATE). # INLET #27 "s - -e" - ® 0.45% _ _ =e'S - - -es - - -e..r - - -e'•r - -es- - - 81s- - - e^5 - .8,s- - - 8' - SECTION A -A ON SHEET C4.2 (35'L x 13'W x 8'D) z O Lu ACHD SD-601, TYPE Io,- RIM:2530.72 ____ 9 - - - - - - - - - - - - - - , _ - - - - - - 7. SB #13 SEE SEEPAGE BED (PRIVATE). SEE DETAIL # 1 , O = W SUMP:2526.56 -- -- SECTION A -A ON SHEET C4.2 (33'L x 13'W x 8'D) - Q INV IN:2527.56 12" (N) _N 0 INV OUT:2527.56 12" (S) - 51.0' 18" ADS N-12 HP 8. SB #14 SEE SEEPAGE BED (PRIVATE). SEE DETAIL #1, \ - O Q25=0.49 8 ® 0.00% SECTION AA ON SHEET C4.2 (46'L x 13'W x 8'D) / � Q100=0.68 I SGT 14 10 L- _J 0 Z D_9. INSTALL GROUND WATER OBSERVATION WELL PER ACHD 1 f RIM:2531.29 (W) SD-627, SHEET C4.3. INSTALL WITHIN THE INFILTRATION CO I RIM:2531.31 (E) BED 5' FROM THE END AND OUTSIDE OF BED A D Q _ INV IN:2527.54 (N) MINIMUM OF 50' FROM THE PERIMETER OF THE BED. Ln - INV OUT:2526.69 (E) cr- �1 INLET BAFFLE:2526.86 10. INSTALL 1,000 GALLON SAND AND GREASE TRAP PER Lu Lu INLET #23 ' 8" OUTLET BAFFLE:2527.44 O 02 ACHD DETAIL BMP 01, SHEET C4.3. c C ACHD SD-601, TYPE I -- J Q25=0.98 Q G Q RIM :2529.45 I Q100=1.37 11. INSTALL CATCH BASIN/SEDIMENT BOX - TYPE A PER J 5\ SUMP:2525.22 ACHD SD-606. J C INV IN:2526.22 12" (E) `? O G INV OUT:2526.22 12" (W) I I d Q25-0.37 Q100=0.51 1 1 1 O 4.3' 12" ADS N-12 HP I ® 0.47% J - - - - - - - - - - - - - - - - - - - - - - - - -- N 10 SGT #12 RIM:2530.02 (N) I I I N RIM:2530.05 (S) , f INV IN:2526.20 (E) SGT #11 10 INV OUT:2525.35 (S) I I INLET BAFFLE:2525.52 -INLET #22 - - - - - - - - - - - - - - - - - - - - RIM:2528.45 (W) OUTLET BAFFLE:2526.10 ACHD SD-601, TYPE I - - RIM:2528.48 (E) Q25=0.74 RIM:2529.45 SUMP:2525.34 INV OUT:24.64 12" (S( g100=1.03 INV OUT:2526.34 12" (W) INV OUT:2523.79 18' (E) INLET BAFFLE:2523.96 �_ Q25=0.37 OUTLET BAFFLE:2524.54 6 I I I Q100=0.52 Q25=0.79 Q100=1.10 40.0' 18" ADS N-12 HP f 28.5' 12" ADS N-12 HP ® 0.00% ® 0.42% I� 5 42.0' 18" ADS N-12 HP - 8 1 ® 0.00% - J O 9 4 O[cm 4.3' 12" ADS N-12 HP E N G I N E E R I N G ® 0.47% W. SAINT CROIX LN. 5725 NORTH DISCOVERY WAYBOISE, IDAHO 83713 PI 6 PI 6 PI PHONE (208) 639-6939 6 PI 6 PI 6 PI 6 PI kmengllp.com 6 PI 6"PI 6"PI L -6••pl - - _ - DESIGN BY: LCK 6'PI g•pl-------- ------ __ __ __ DRAWN BY: LCK 6"PI 6"PI 6"PI 6"PI 6'•PI 6"PI 6"PI 6"PI 6'PI I 6"PI CHECKED BY: LCK DATE: DULY 2022 PROJECT: 21-240 C4.0 z O U z O U O LL H O z 1 Q z J Lu IY a INLET #5 ACHD SD-601, TYPE I RIM:2535.90 INLET #6 ACHD SD-601, TYPE I RIM:2535.90 =�F SUMP:2531.65 4rINV IN:2532.65 12" (N) INV OUT:2532.65 12" (S) Q25=0.22 Q100=0.30 4.3' 12" ADS N-12 HP. 0.46% \I I I INLET #7 ACHD SD-601, TYPE I RIM:2537.48 SUMP:2533.37 INV OUT:2534.37 12" (S) Q25=0.89 Q100=1.24 i Q -INV UU1:2S51./d 16 (E) INV OUT:2533.36 18" (E)J OUTLET BAFFLE:2532.53 INLET BAFFLE:2INLET BAFFLE:2533.53 2532. Q25=0.53 OUTLET BAFFLE:2534.11 0 m Q100=0.75 025=1.75 E 0100=2.44 I ~ I � I 74.0' 18" ADS N-12 HP ® 0.00% 4.3' 12" ADS IN-12 HP ® 0.46% 1 u 1 m INLET #12 ACHD SD-601, TYPE I _ RIM:2532.79 SUMP:2528.40 69.5' 12" ADS N-12 HP INV IN:2529.40 12" (E) ® 0.40% INV OUT:2529.40 12" (W) Q25=0.71 INLET #11 Q100=0.98 ACHD SD-601, TYPE I RIM:2532.79 'm SUMP:2528.68 o INV OUT:2529.68 12" (W) Q25=0.77 Q 100=1 .07 r INLET #28 ACHD SD-601, TYPE I 12"SD 9 RIM:2533.08 r SUMP:2528.97 y SGT #6 10 \ - - INV OUT:2529.97 12' (S) - RIM:2533.37 (S) Q25=0.73 - Q100=1.01 INLET 29 RIM:2533.41 (N) - #---------- 28.6' 12" ADS N-12 HP ACHD SD-601, TYPE I _ NINV OUT: 29.38 12" (E) �w - w_® 0.42% - - - - - - 8'RIM:2533.10 _8"w 4 8"w 8 w 8'w 8-W8"w-� INV OUT:2528.53 18' (N) SUMP:2528.85 INLET BAFFLE:2528.70 - - - - - - - - W. LITTLE RAVEN LN. - - - - - a^s-OUTLET BAFFLE:2529.28 1 - a"s- - - - - - �.r INV IN:2529.85 12' (N) _ - - - - -ems - - �� - _ �,� _ -� - - a"s- - - 025-1.47 - - - INV OUT:2529.85 12' (S) Q100=2.06 - �g p 9 Q25=0.72 ----------------------1 Q100=1.01 \ 4.3' 12" ADS N-12 HP / 7 7 0.00% ADS N-12 HP a 0.46% I fj N I SGT #15 10 L- J L- J 141.0' 18" ADS N-12 HP RIM:2533.68 (W) ® 0.00% RIM:2533.72 (E) INLET #14 INV IN:2529.83 (N) ACHD SD-601, TYPE INV OUT:2528.98 (E) O3 o 1.24 INLET BAFFLE:2529.15 SUMP:226.I RIM:25 526,85 OUTLET BAFFLE:2529.73 W INV IN:2527.85 12" (E) Q005 INV OUT:2527.85 12' (W) 0100=2.2.02 Q25=0.40 Q100=0.56 6 .05'4012" ADS N-12 HP N I SD II II INLET ACHD SD-601, TYPE I - � '3.2' 12" ADS N-12 HP ��RIM*2531.24 `® 0.62% 2 _I II 'SGT #7 10 SUMP:2527.13 - RIM:2531.80 (S) I- INV OUT2528.13 12" (W) a "SRIM:2531.86 (N) I Q10000,52 - - INV IN:2527.83 12" (E) - _ INV OUT:2526.98 18" (N) INLET BAFFLE:2527.15 1 OUTLET BAFFLE:2527.73 Q25=0.77 Q100=1.08� 76.0' 18" ADS N-12 HP - - ® 0.00% I a 9 INLET #16 ACHD SD-601, TYPE I RIM:2530.61 6 SUMP:2526.42 INV IN:2527.42 12" (E) O2 INV OUT:2527.42 12" (W) ro Q25=0.82 Q100=1.15 81.9' 12" ADS N-12 HP I II 9 12' D INLET #15 L I ACHD SD-601, TYPE I 4.4' 12" ADS N-12 HP RIM:2530.86 0.45% SUMP:2526.75 uI INV OUT:2527.75 12" (W) SGT #8 10 Q25=0.71 RIM:2531.19 (S) Q1DQ=0.99 - - - - - - - - - - - - - - - - PI ,IRIM:2531.20 (N) r INV IN:2527.40 12" (E) 8 PI 8"PI 8"PI-�8"PI 6"PI - - - - - - 6"PI 6'PI INV OUT:2526.55 18" (N) NLET BAFFLE:2526.72 OUTLET BAFFLE:2527.30 I \ I s, Q25=1.53 6"P1 Q100=2.14 F n \- TOE TOE �OE TOE \ \ \ TOP - - TOP - O - T TOE TOE TOE TOE TOE TOE P - - TOP - - TOP - - TOP PI I 6"PI 6"PI TOE TOE TOE TO TOE TOE TOE TOE TOP TOP TOP TOP BLOCK 1 O IBlv s'w - - e'w - e'w - - iD =a's=_-a^s---es-- r TOE TOE E TOE TO TO, TOP ----------- C] so tog is@ Plan Scale: 1" = 90' SHEET NOTES A. SEE SHEET C1.1 FOR GENERAL, ACHD, AND UTILITY NOTES. B. SEE SHEET C4.0 FOR ADDITIONAL NOTES. KEYNOTES 1. SIB #3 SEE SEEPAGE BED (PUBLIC). SEE DETAIL #1, SECTION A -A ON SHEET C4.2 (251 x 13'W x 8'D) 2. SIB #4 SEE SEEPAGE BED (PUBLIC). SEE DETAIL #1, SECTION A -A ON SHEET C4.2 (821 x 13'W x 8'D) 3. SIB #5 SEE SEEPAGE BED (PUBLIC). SEE DETAIL #1, SECTION A -A ON SHEET C4.2 (271 x 11.5'W x 8'D) 4. SIB #6 SEE SEEPAGE BED (PUBLIC). SEE DETAIL #1, SECTION A -A ON SHEET C4.2 (691 x 13'W x 8'D) 5. SIB #7 SEE SEEPAGE BED (PRIVATE). SEE DETAIL 1, SECTION A -A ON SHEET C4.2 (361 x 13'W x 8'D 6. SIB #8 SEE SEEPAGE BED (PRIVATE). SEE DETAIL 1, SECTION A -A ON SHEET C4.2 (711 x 13'W x 8'D 7. SIB #15 SEE SEEPAGE BED (PRIVATE). SEE DETAIL #1, SECTION A -A ON SHEET C4.2 (681 x 13'W x 8'D) 8. SIB #16 SEE SEEPAGE BED (PRIVATE). SEE DETAIL #1, SECTION A -A ON SHEET C4.2 (441 x 13'W x 8'D) 9. INSTALL GROUND WATER OBSERVATION WELL PER ACHD SD-627, SHEET C4.3. INSTALL WITHIN THE INFILTRATION BED 5' FROM THE END AND OUTSIDE OF BED A MINIMUM OF 50' FROM THE PERIMETER OF THE BED. 10.INSTALL 1,000 GALLON SAND AND GREASE TRAP PER ACHD DETAIL BMP 01, SHEET C4.3. --33.5' 12" ADS N-12 HP -CAP 0.45% f II INLET #10 ACHD SD-601, TYPE I =RIM:2540.48 �S U M P:2536.22 INV IN:2537.22 12" (N) INV OUT:2537.22 12" (S) Q25=0.28 Q100=0.39 11 II 1 II 1 : 1 4.3' 12" ADS N-12 HP © 0.47% II IQ� Im I al a I NI a I II I I L_e I I I INLET #30 _ _ ACHD SD-601, TYPE I F- , RIM:2538.16 r I I SUMP:2534.05 / 1 INV OUT:2535.05 12" (S) / - Q25=0.49 / w Q100=0.68 - - - -28.5' 12" ADS N-12 HP- ® 0.42% / ` 8^w 8"w 8"w 8"w 8^w 8'w / 4.3' 12" ADS N-12 HP j ----- { -@ 0.47% - --------� INLET #31 ACHD SD-601, TYPE I RIM:2538.16 SUMP:2533.93 INV IN:2534.93 12" (N) INV OUT:2534.93 12" (S) Q25-0.45 Q100=0.63 s INLET #9 ACHD SD-601, TYPE Imo- RIM:2540.48\ SUMP:2536.37� \INV OUT:2537.37 12" (S) Q25=0.23 �2 Q100=0.32 32.1' 18" ADS N-12 HP� ® 0.00% 3 ACHD STORM DRAIN EASEMENT (3SGT #5 RIM:2541.06 (E) RIM:2541.11 (W) INV IN:2537.20 12" (N) INV OUT:2536.35 18" (W) INLET BAFFLE:2536.25 OUTLET BAFFLE:2537.10 Q25-0.51 Q 100=0.71 �49.0' 18" ADS N-12 HP ® 0.00% SGT #16 10 RIM:2538.72 (W) RIM:2538.75 (E) INV IN:2534.91 (N) INV OUT:2534.06 (E) INLET BAFFLE:2534.23 OUTLET BAFFLE:2534.81 Q25=0.94 Q100=1.31 J a 0 Ln z O N � w O z0 Q z ma Q W � C Q G J O d N z a ♦2 z Lu 2 W O ♦C2 G Lu Q C� G fi 0 V) km E N G I N E E R I N G 5725 NORTH DISCOVERY WAY BOISE, IDAHO 83713 PHONE (208) 639-6939 kmengllp.com DESIGN BY: LCK DRAWN BY: LCK CHECKED BY: LCK DATE: JULY 2022 PROJECT: 21-240 C4.1 EN 1,000 GALLON r► A SAND AND GREASE TRAP PER ACHD REQUIREMENTS. REFER TO ACHD DETAIL BMP 01, SHEET 5 LF OF 18"0 * V) ADS N-12 HP w J �i r� amx SD SD I -------- - - - - - - - - - - - - - - - - - - - - - - - - - S W N L J ~p w S 3 N � *18"0 PERFORATED ADS N-12 HP. TRANSITION 5' IN BED NON -PERFORATED TO Ly A PERFORATED PIPE Ilf� LENGTH VARIES, SEE TABLE THIS SHEET -►ill 1,000 GALLON PLAN VIEW SAND AND GREASE TRAP PER ACHD REQUIREMENTS. REFER TO ACHD DETAIL BMP 01. WATERTIGHT CONNECTION LOCATIONS, ELEVATIONS, AND ADDITIONAL INFORMATION PER 18"0 SOLID WALL ADS N-12 HP STORMWATER PLAN SHEETS (EXTEND 5' INTO SEEPAGE BED) 18"0 PERFORATED ADS * FINISH GROUND N-12 HP 8" ADS CAP n ---- 0% SLOPE ---- MINIMUM OF 20"J BAFFLE SPACING 4" OF J" CHIPS PIPE GROUND WATER OBSERVATION WELL PER DETAIL. EXTEND MINIMUM OF 1' BELOW THE BOTTOM OF SAND LAYER PROFILE VIEW SECTION A - PLAN AND PROFILE r� A CATCH BASIN/SEDIMENT BOX - TYPE A PER ACHD SD-606. 5 LF OF 18"0 * vi ADS N-12 HP w w SD - - - - - - - - - - - - - - - - - ¢a= ---------------- xwcn ow= 3 *18"0 PERFORATED ADS N-12 HP. TRANSITION 5' IN BED NON -PERFORATED TO Ly A PERFORATED PIPE III` -►III LENGTH VARIES, SEE TABLE THIS SHEET PLAN VIEW CATCH BASIN/SEDIMENT BOX - TYPE A PER ACHD SD-606. LOCATIONS, ELEVATIONS, AND WATERTIGHT CONNECTION ADDITIONAL INFORMATION PER STORMWATER PLAN SHEETS 18"0 SOLID WALL ADS N-12 HP (EXTEND 5' INTO SEEPAGE BED) 18"0 PERFORATED ADS * FINISH GROUND N-12 HP ------- 18" ADS CAP n ---- 0% SLOPE ---- MINIMUM OF 20"J BAFFLE SPACING 4" OF J" CHIPS PIPE GROUND WATER OBSERVATION WELL PER DETAIL. EXTEND MINIMUM OF 1' BELOW THE BOTTOM OF SAND LAYER PROFILE VIEW SECTION B - PLAN AND PROFILE 5' SIDEWALK PER ACHD SUPPLEMENTAL STANDARD DRAWING SD-709. ELEV. - "A" (MIN.) ELEV. - "B" ELEV. - "C' NO TREES ARE ALLOWED WITHIN 10' OF THE OUTSIDE PERIMETER OF THE SEEPAGE BED 0 ELEV. - "D" WIDTH VARIES, SEE MAX. HSGW `- TABLE THIS SHEET OR ROCK ELEVATION 4 FINISHED GROUND CURB AND GUTTER FPER ROADWAY PLANS. 0 KEY o 1. ISPWC 801 OR ASTM C33 FILTER SAND. 2. 3/4" - 2" ANGULAR ROCK. 3. 18"0 PERFORATED PIPE. INSTALL PERFORATIONS PER ACHD STORMWATER DESIGN GUIDELINES DETAIL BMP 20 AND DETAIL ON THIS SHEET. 4. SUITABILITY OF SUBGRADE TO BE VERIFIED BY GEOTECHNICAL ENGINEER. 5. NON -WOVEN FABRIC SHALL BE PROPEX GEOTEX 401 OR APPROVED EQUAL MEETING ACHD STORMWATER DESIGN GUIDELINES SECTION 8202.23. OVERLAP MINIMUM OF 1-FT TOP AND SIDES ONLY. 6. FOR SEEPAGE BEDS IN THE PUBLIC RIGHT-OF-WAY A MINIMUM OF 1.0-FT COVER FROM TOP OF BED TO PAVEMENT SUBGRADE. INSTALL WOVEN GEOTEXTILE FABRIC OVER TOP OF BED. WOVEN FABRIC SHALL BE PROPEX GEOTEX 401F OR APPROVED EQUAL MEETING ACHD STORMWATER DESIGN GUIDELINES SECTION 8202.23. SECTION VIEW A -A: SEEPAGE BEDS WITHIN PUBLIC ROW NO TREES ARE ALLOWED WITHIN 5' SIDEWALK PER ACHD SUPPLEMENTAL 10' OF THE OUTSIDE PERIMETER STANDARD DRAWING SD-709. OF THE SEEPAGE BED CURB AND GUTTER PER ROADWAY PLANS. PAVEMENT SECTION PER ELEV. - "A" (MIN.) z ROADWAY DETAILS ELEV. - "B" "C" Tot ELEV. - z 3 N 5 w J 5 io ~ �w aw W N ELEV. - "D" z iQ E WIDTH VARIES, SEE MAX. HSGW TABLE THIS SHEET EL ROCK ELEVATION 4 1KEY 0 1. ISPWC 801 OR ASTM C33 FILTER SAND. 2. 3/4" - 2" ANGULAR ROCK. 3. 18"0 PERFORATED PIPE. INSTALL PERFORATIONS PER ACHD STORMWATER DESIGN GUIDELINES DETAIL BMP 20 AND DETAIL ON THIS SHEET. 4. SUITABILITY OF SUBGRADE TO BE VERIFIED BY GEOTECHNICAL ENGINEER. 5. NON -WOVEN FABRIC SHALL BE PROPEX GEOTEX 401 OR APPROVED EQUAL MEETING ACHD STORMWATER DESIGN GUIDELINES SECTION 8202.23. OVERLAP MINIMUM OF 1-FT TOP AND SIDES ONLY. 6. FOR SEEPAGE BEDS IN THE PUBLIC RIGHT-OF-WAY A MINIMUM OF 1.0-FT COVER FROM TOP OF BED TO PAVEMENT SUBGRADE. INSTALL WOVEN GEOTEXTILE FABRIC OVER TOP OF BED. WOVEN FABRIC SHALL BE PROPEX GEOTEX 401F OR APPROVED EQUAL MEETING ACHD STORMWATER DESIGN GUIDELINES SECTION 8202.23. SECTION VIEW B-B: SEEPAGE BEDS WITHIN PUBLIC ROW SEEPAGE BED TABLE SEEPAGE BED TYPE SECTION BED LENGTH (FT) BED WIDTH (FT) BED DEPTH (FT) ELEVATION "A" ELEVATION "B" ELEVATION "C" ELEVATION "D" GROUND WATER EL. DESIGN VOLUME (CF) DESIGN INFILTRATION RATE (IN/HR) SB #1 PUBLIC A 65 13.0 8.0 2530.54 2528.50 2525.88 2520.50 2517.3f 3,252 8.0 SB #2 PUBLIC A 58 13.0 8.0 2533.08 2531.00 2528.41 2523.00 2519.4f 2,904 8.0 SB #3 PUBLIC A 25 13.0 8.0 2536.49 2534.40 2531.78 2526.40 2523.0t 1,248 8.0 SB #4 PUBLIC A 82 13.0 8.0 2538.04 2536.00 2533.36 2528.00 2525.0t 4,094 8.0 SB #5 PUBLIC A 27 11.5 8.0 2541.11 2539.50 2536.35 2531.50 2528.5t 1,190 8.0 SB #6 PUBLIC A 69 13.0 8.0 2533.41 2531.90 2528.53 2523.90 2520.8t 3,442 8.0 SB #7 PUBLIC A 36 13.0 8.0 2531.88 2529.80 2526.98 2521.80 2517.9f 1,801 8.0 SB #8 PUBLIC A 71 13.0 8.0 2531.17 2529.10 2526.55 2521.10 2516.4f 3,577 8.0 SB #9 PRIVATE B 30 8.0 7.5 2527.77 2524.75 2521.77 2517.25 2514.1t 865 8.0 SB #10 PRIVATE B 73 8.0 8.0 2527.45 2524.40 2522.40 2516.40 2512.9f 2,261 8.0 SB #11 PRIVATE A 37 13.0 8.0 2528.46 2526.40 2523.79 2518.40 2514.8f 1,848 8.0 SB #12 PRIVATE A 35 13.0 8.0 2530.03 2528.00 2525.35 2520.00 2516.3f 1,729 8.0 SB #13 PRIVATE A 33 13.0 8.0 2531.25 2529.25 2526.58 2521.25 2517.9f 1,662 8.0 SB #14 PRIVATE A 46 13.0 8.0 2531.26 2529.20 2526.69 2521.20 2517.4f 2,286 8.0 SB #15 PRIVATE A 68 13.0 8.0 2533.71 2531.70 2528.98 2523.70 2519.9f 3,384 8.0 SB #16 PRIVATE A 44 13.0 8.0 2538.72 2536.70 2534.06 2528.70 2525.6t 2,198 8.0 GENERAL NOTES A. GROUNDWATER ELEVATIONS ARE EXPECTED TO REMAIN AT OR BELOW 13 FEET FROM EXISTING GROUND SURFACE. THE DESIGN INFILTRATION RATE IS 8 IN/HR BASED ON THE TEST PIT LOGS, WHICH SHOW POORLY GRADED GRAVEL AT THE APPROXIMATE BOTTOM DEPTH OF THE PROPOSED SEEPAGE BEDS. FOR ADDITIONAL INFORMATION REFER TO THE GEOTECHNICAL ENGINEERING REPORT "POLLARD LANE REALIGNMENT - POLLARD LANE & CHINDEN BOULEVARD" PREPARED BY MTI, DATED AUGUST 31, 2016. B. ALL DRAINAGE STRUCTURES SHALL BE HS25 OR GREATER LOAD RATED. C. ALL GEOTEXTILE SEAMS SHALL OVERLAP 1 FOOT MINIMUM. D. BED WIDTH SHALL REMAIN CONSTANT. E. IF ROCK IS ENCOUNTERED, CONTRACTOR MUST HAVE A PERCOLATION TEST PERFORMED BY A SOILS ENGINEER AFTER SEEPAGE BED IS FULLY EXCAVATED. (NOTE: AN ACHD INSPECTOR MUST BE PRESENT FOR THE TEST). IF THE PERCOLATION IS LESS THAN SPECIFIED BY THE SOILS REPORT AND ENGINEER, CONTRACTOR MAY NEED TO BLAST OR BORE TO CREATE CONDUIT FOR DRAINAGE TO OCCUR OR RE -DESIGN THE SYSTEM TO ACHIEVE THE REQUIRED INFILTRATION. F. STORAGE VOLUME DOESN'T INCLUDE SAND WINDOW. G. WATER SERVICES, SEWER SERVICES, AND PRESSURE IRRIGATION MAINS CROSSING SEEPAGE BEDS SHALL BE INSTALLED PER ACHD REQUIREMENTS. H. FOR UNDERGROUND INFILTRATION SYSTEMS, INSTALL ELECTRONIC MARKERS ON EACH CORNER OF THE FACILITY. THE CONTRACTOR SHALL COORDINATE WITH THE ACHD INSPECTION DEPARTMENT FOR PLACEMENT OF THE MARKERS DURING CONSTRUCTION AND PRIOR TO BACKFILLING. I. CONTRACTOR SHALL VERIFY INFILTRATION RATE AFTER THE FACILITY IS FULLY EXCAVATED WITH THE ACHD INSPECTOR PRESENT. J. CONTRACTOR SHALL NOTIFY THE ENGINEER IMMEDIATELY IF GROUNDWATER IS ENCOUNTERED WITHIN 3-FEET OF THE BOTTOM DESIGN ELEVATION FOR ANY INFILTRATION FACILITY AND/OR IF IT IS HIGHER THAN ANTICIPATED. O a 18" PIPE 18" PERF PIPE WQ '% nS 00. PERFORATION SCHEDULE 3/8" PERFORATIONS IN VALLEY OF CORRUGATED PIPE. 5 EA ON 18". /At a 0 Ln Z 0 N > w W K P� OF Ln z I..L z Lu Lu ON J -o Lu O H cn km E N G I N E E R I N G 5725 NORTH DISCOVERY WAY BOISE, IDAHO 83713 PHONE (208) 639-6939 kmengllp.com DESIGN BY: LCK DRAWN BY: LCK CHECKED BY: LCK DATE: JULY 2022 PROJECT: 21-240 SEEPAGE BED DETAIL #1 NTS C4.2 SECTION N.T.S. 201 / V, Tl R-VISION P <3) PLAN CONCRETE COLLAR N.T.S. ro� SECTION CONCRETE COLLAR N.T.S. IDAII F, IAN)ARL.: I(,z rU u,, ORI\S GR iNI,;dA1 N sIVD IZE D P Av,dNG EACH-) HUFF. FH. :,UFr'. FE FNT) , cF L=GEVD C� 'N- L COVER, 8" DIA. WA-ESIGHT GALVANIZED SEEL HCL' DOWN COVER AN-) CAN 5-=R �) ; R Hcl I IID 9/16" H-AD AND SAF IF-RFA.)S, CASE-GD (') CONCR=T= COLLAR), CLASS 3000 (I_PWC _ETION C3) i DA IOI FS OR SI OTS C.JT INTO PIP- AT 3" ON SETTER b� IRA,CFR W,R- SHALL EF FLACLD CN OJISIDE OF PVC PIPE, MI,VJM 18 GAJGL, IRSJLAlL , SIKC,_F- KL! CSOR CC LEE TIRE, N�UL TiUN JLOR ST L BE GRLEN WITH 1TH-L 6' D4METEP - iLS E TA_L BE PEPFORATED PC,. STM D 0C 5, SD - 35. A _LIES BACKFIL= IN A 'IT PEG R- IPE. DR _LLJ WELS MAY JSE "" P '- .O K N YER LILTE F 9C ARDUND CPENINATD 3M, LAHR OVER F-S/-)FA N OC C fP- O-YI - NF FVF RFINFORCFIIFKT A 1 i2 i CY .� CKF_L 11 ILRI _ IJ P1 ICI- IJPA IIEJI.. FOR CSER✓Al JL WELLS CA ED I -IN A Bf/I FACT_Iv. J F PIPE B D. JJ C.- FOR 0-5,FR,'ATI,3V Ao S I..CATFD Cl,-_ -)F RMP FHCII -.s NJ TO 1, C1NUM1.I-R C9SFR' IICV 4-11S ARF `CH MF,ASIRFMF VI OI CRCI. VI;NJAIFR FVFIS NJ -TIN CR NFAID f RM DR .IN CI I AC II 1 ' 2. TI IIS DFTAII IS - OR AFI S IRS A. I F7 BY 7RI1 INC OR F3" FXCAVATFD P TS CCA-L^,N 0 GROUND'o�iA FR ORSFRVATION �AFIIS S IA f3E AP�ROVFD 3Y AC IN 4_ CBSE� vATON WCLS NOT AL_2,AED IN CURB OR VALLEY G(,TTEF SECTION 20'7 ACHD REVI`IOY ICAT _,T NE RDS P��) ND /VATTP STANDARD DRAWING CR F 1H1 t 1^:0-1KS 7 P:ER','ATICN -1 1 SD-627 'r.. HC `,IiF 'I F`a1FN-) 2 OF 2 r - - I I I I 0 I I I A __a q �10 �10 I I z I I L- - - - - - - - - - - - - - - - - - - - - - J PLAN VIEW 6 6 N.T.S. 3 =� 5 Z � 4 OUTLET FLO o BAFFLE WALL r ELEV B —47 FLOW Ju ELEVD INLET BAFFLE WALL ELEV C 20" STD SECTION A -A N.T.S. NOTES 1. SAND AND GREASE TRAP USED FOR SUBSURFACE FACILITIES ONLY LEGEND: RMANHOLE FRAME AND COVER PER SD-617 (TYPICAL) LOCATION AND FI_ FI_FV. PER DESIGN PLANS (TYPICAI_1 65H 1-FT USE GRADE RINGS (TYPICAL) 1-FT < H <- 2-FT USE 24" DIA RCP RISER 2-FT < H <- 10-FT USE MANHOLE CONE & 48" DIA RISERS aO EL. A > EL. B BY 0.10' MIN EL. D < EL. B BY 0.10' MIN EL. C < EL. B BY 0.50' MIN. UNLESS OTHERWISE APPROVED BY ACHD s WATERTIGHT SEAL e PRECAST BOX MANUFACTURER SHALL MARK FLOW DIRECTION AND LABEL INLET OR OUTLET ON SIDE OF BOX 2015 SAND AND GREASE TRAP STANDARD DRAwINc ACHD SORMWATER GUIDELINES DESIGN B M P 01 1 OF 2 EN P� OF /At 0 Ln Z O L Lu tz r-I O z z0 oa U-)o ma �o �or_ LLJ a J J d km E N G I N E E R I N G 5725 NORTH DISCOVERY WAY BOISE, IDAHO 83713 PHONE (208) 639-6939 kmengllp.com DESIGN BY: LCK DRAWN BY: LCK CHECKED BY: LCK DATE: JULY 2022 PROJECT: 21-240 C4.3 APPENDIX B - TABLES Table 1- Peak Flow Rates and Runoff Volumes Post -Development Peak Flow Rates (cfs) Tc (min.) 25-yr 100-yr Basin A-1 10.0 0.69 0.96 Basin A-2 10.0 0.70 0.98 Basins A-1- A-2 10.0 1.39 1.94 Basin B-1 10.0 0.64 0.89 Basin B-2 10.0 0.60 0.84 Basins B-1- B-2 10.0 1.24 1.73 Basin C-1 10.0 0.32 0.44 Basin C-2 10.0 0.22 0.30 Basins C-1- C-2 10.0 0.53 0.75 Basin D-1 10.0 0.89 1.24 Basin D-2 10.0 0.87 1.21 Basins D-1- D-2 10.0 1.75 2.44 Basin E-1 10.0 0.23 0.32 Basin E-2 10.0 0.28 0.39 Basins E-1- E-2 10.0 0.51 0.71 Basin F-1 10.0 0.77 1.07 Basin F-2 10.0 0.71 0.98 Basins F-1- F-2 10.0 1.47 2.06 Basin G-1 10.0 0.37 0.52 Basin G-2 10.0 0.40 0.56 Basins G-1- G-2 10.0 0.77 1.08 Basin H-1 10.0 0.71 0.99 Basin H-2 10.0 0.82 1.15 Basins H-1- H-2 10.0 1.53 2.14 Basin 1-1 10.0 0.37 0.52 Basin J-1 10.0 0.42 0.59 Basin J-2 10.0 0.55 0.76 Basins J-1- J-2 10.0 0.97 1.35 Basin K-1 10.0 0.33 0.47 Basin K-2 10.0 0.46 0.64 Basins K-1- K-2 10.0 0.79 1.10 Basin L-1 10.0 0.37 0.52 Basin L-2 10.0 0.37 0.51 Basins L-1- J-2 10.0 0.74 1.03 Basin M-1 10.0 0.34 0.48 Basin M-2 10.0 0.37 0.51 Basins M-1- M-2 10.0 0.71 0.99 Basin N-1 10.0 0.49 0.68 Basin N-2 10.0 0.49 0.68 Basins N-1- N-2 10.0 0.98 1.37 Basin 0-1 10.0 0.73 1.01 Basin 0-2 10.0 0.72 1 1.01 Basins 0-1- 0-2 10.0 1.45 2.02 Basin P-1 10.0 0.49 0.68 Basin P-2 10.0 0.45 0.63 Basins P-1- P-2 10.00 0.94 1.31 Post -Development Runoff Volumes 100yr Runoff Volume +25 Sediment (CF) Basins A-1- A-2, SB #1 3,252 Basins B-1- B-2, SB #2 2,904 Basins C-1- C-2, SB #3 1,248 Basins D-1- D-2, SB #4 4,094 Basins E-1- E-2, SB #5 1,190 Basins F-1- F-2, SB #6 3,442 Basins G-1- G-2, SB #7 1,801 Basins H-1- H-2, SB #8 3,577 Basin 1-1, SB #9 865 Basins J-1- J-2, SB #10 2,261 Basins K-1- K-2, SB #11 1,848 Basins L-1- L-2, SB #12 1,729 Basins M-1- M-2, SB #13 1,662 Basins N-1- N-2, SB #14 2,286 Basins 0-1- 0-2, SB #15 3,384 Basins P-1- P-2, SB #16 2,198 APPENDIX C - CALCULATIONS POST -DEVELOPMENT 25-YEAR CALCULATIONS ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge post-develo Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin A-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.69 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 927 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 806 ft. 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 93 ft' Primary Treatment/StorageBasin V 835 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 927 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 16,598 4,936 0.49 0.95 0.10 0.76 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.1O' Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin A.xlsm Version 10.5, November 2018 7/18/2022, 7:30 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin A-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 9 Calculate the Post -Development peak discharge (QPeak) i Q,A 5 0.70 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 942 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 820 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 94 ft' Primary Treatment/StorageBasin V 848 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 942 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 16,877 4,935 0.50 0.95 0.10 0.76 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin A.xlsm Version 10.5, November 2018 7/18/2022, 7:32 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins A-1- A-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User Calculate (10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (CiPeak) Qp,,k 1.39 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,870 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 1,626 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 187 ft, V 1,683 ft' V 1,870 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 33,475 9,871 1.00 0.95 0.10 0.76 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin A.xlsm Version 10.5, November 2018 7/18/2022, 7:32 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin B-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 0 i 1.85 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.64 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 858 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 746 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 86 ft' Primary Treatment/StorageBasin V 773 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 858 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 15,350 4,705 0.46 0.95 0.10 0.75 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin B.xlsm Version 10.5, November 2018 7/18/2022, 7:33 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin B-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 1.85 0.60 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 812 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 706 ft, 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 81 ft' Primary Treatment/StorageBasin V 730 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 812 W flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 14,525 4,337 0.43 0.95 0.10 0.75 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.l0-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin B.xlsm Version 10.5, November 2018 7/18/2022, 7:34 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins B-1 - B-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 5 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 1.24 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,670 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 1,452 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 167 ft' V 1,503 ft' V 1,670 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 29,875 9,042 0.89 0.95 0.10 0.75 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin B.xlsm Version 10.5, November 2018 7/18/2022, 7:34 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin C-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 7,679 1,824 0.22 0.95 0.10 0.79 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 1.85 in/ 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.32 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V W V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 371 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 43 ft' Primary Treatment/StorageBasin V 0 384 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 426 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.3, Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin C.xlsm Version 10.5, November 2018 7/18/2022, 7:35 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin C-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 5 0.22 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 291 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 253 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 29 ft' Primary Treatment/Storage Basin V 262 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 291 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 5,199 1,642 0.16 0.95 0.10 0.75 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin C.xlsm Version 10.5, November 2018 7/18/2022, 7:35 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins C-1- C-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate [10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 9 Calculate the Post -Development peak discharge (CiPeak) i Qpe,k 1.85 0.53 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 717 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V„ 624 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 72 ft' Primary Treatment/StorageBasin V 646 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 717 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 12,878 3,466 0.38 0.95 0.10 0.77 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin C.xlsm Version 10.5, November 2018 7/18/2022, 7:36 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin D-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 21,316 6,130 0.63 0.95 0.10 0.76 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.89 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,190 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 1,035 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 119 ft' Primary Treatment/StorageBasin V 1,071 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,190 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin D.xlsm Version 10.5, November 2018 7/18/2022, 9:38 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin D-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 20,885 5,743 0.61 0.95 0.10 0.77 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User Calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (CiPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) 0.87 cfs V 1,164 ft' 95th 0.60 in Vr, 1,012 ft, cfs V 116 ft, V 1,048 W V 1,164 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin D.xlsm Version 10.5, November 2018 7/18/2022, 7:47 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins D-1 - D-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 5 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 1.75 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 2,354 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 2,047 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 235 ft' V 2,118 ft' V 2,354 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 42,201 11,873 1.24 0.95 0.10 0.76 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin D.xlsm Version 10.5, November 2018 7/18/2022, 7:47 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin E-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from ICIF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Clpeak 0.23 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 310 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 270 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 31 ft' Primary Treatment/StorageBasin V 279 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 310 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 5,594 1,274 0.16 0.95 0.10 0.79 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin E.xlsm Version 10.5, November 2018 7/18/2022, 7:48 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin E-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User Calculate [10 Min 8 Determine the average rainfall intensity (i) from IDF Curve based on Tici 9 Calculate the Post -Development peak discharge (QPeak) Qpe,k 1.85 0.28 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 374 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V„ 325 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 37 ft' Primary Treatment/StorageBasin V 336 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 374 ft' rlirk to Ghnw Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 6,771 1,234 0.18 0.95 0.10 0.82 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin E.xlsm Version 10.5, November 2018 7/18/2022, 7:48 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins E-1 - E-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate [10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 9 Calculate the Post -Development peak discharge (CiPeak) i Qpe,k 1.85 0.51 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 684 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V„ 595 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 68 ft' Primary Treatment/StorageBasin V 616 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 684 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 12,365 2,508 0.34 0.95 0.10 0.81 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calk: Basin E.xlsm Version 10.5, November 2018 7/18/2022, 7:48 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin F-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 18,760 2,570 0.49 0.95 0.10 0.85 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from ICIF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Clpeak 0.77 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,031 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 896 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 103 ft' Primary Treatment/StorageBasin V 928 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,031 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin F.xlsm Version 10.5, November 2018 7/18/2022, 7:49 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin F-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 9 Calculate the Post -Development peak discharge (QPeak) Q,A 5 0.71 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 948 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 824 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 95 ft' Primary Treatment/Storage Basin V 853 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 948 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 17,224 2,611 0.46 0.95 0.10 0.84 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin F.xlsm Version 10.5, November 2018 7/18/2022, 7:50 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins F-1- F-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 5 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 1.47 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,979 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 1,721 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 198 ft' V 1,781 ft' V 1,979 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 35,984 5,181 0.95 0.95 0.10 0.84 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin F.xlsm Version 10.5, November 2018 7/18/2022, 7:50 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin G-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from ICIF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Clpeak 0.37 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 500 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 435 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 50 ft' Primary Treatment/StorageBasin V 450 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 500 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 9,102 1,273 0.24 0.95 0.10 0.85 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin G.xlsm Version 10.5, November 2018 7/18/2022, 7:52 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin G-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 9 Calculate the Post -Development peak discharge (CiPeak) 1.85 0,40 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 535 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) Vrr 465 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 54 ft' Primary Treatment/StorageBasin V 482 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 535 ft' rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 9,760 1,107 0.25 0.95 0.10 0.86 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin G.xlsm Version 10.5, November 2018 7/18/2022, 7:53 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins G-1 - G-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc i 5 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Q,A 0.77 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,035 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 900 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 104 ft' Primary Treatment/Storage Basin V 932 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,035 ft' rlirk to Ghnw Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 18,862 2,380 0.49 0.95 0.10 0.85 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin G.xlsm Version 10.5, November 2018 7/18/2022, 7:53 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin H-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from ICIF Curve based on Tc 9 Calculate the Post -Development peak discharge (QPeak) i Clpeak 1.85 0.71 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 953 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 829 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 95 ft' Primary Treatment/StorageBasin V 858 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 953 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 17,388 1,903 0.44 0.95 0.10 0.87 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin H.xlsm Version 10.5, November 2018 7/18/2022, 7:54 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin H-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User Calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (CiPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) 0.82 cfs V 1,104 ft' 95th 0.60 in Vr, 960 ft, cfs V 110 ft, V 993 W V 1,104 W rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 20,087 2,744 0.52 0.95 0.10 0.85 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin H.xlsm Version 10.5, November 2018 7/18/2022, 7:54 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins H-1 - H-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 5 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 1.53 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 2,057 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V„ 1,788 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 206 ft' V 1,851 ft' V 2,057 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 37,475 4,647 0.97 0.95 0.10 0.86 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin H.xlsm Version 10.5, November 2018 7/18/2022, 7:54 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin 1-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 1 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from ICIF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.37 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 498 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 433 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 50 ft' Primary Treatment/StorageBasin V 448 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 498 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 9,184 0.21 0.95 0.95 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin I.xlsm Version 10.5, November 2018 7/18/2022, 7:55 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin 1-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 10,455 0.24 0.95 0.95 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 1.85 in/ 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.42 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V W V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 493 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 57 ft' Primary Treatment/StorageBasin V 510 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 566 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.3, Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin J.xlsm Version 10.5, November 2018 7/18/2022, 7:55 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin J-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate [10 Min 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 9 Calculate the Post -Development peak discharge (CiPeak) i Qpe,k 1.85 0.55 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 734 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V„ 638 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 73 ft' Primary Treatment/StorageBasin V 660 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 734 ft' rlirk to Ghnw Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 13,544 0.31 0.95 0.95 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin J.xlsm Version 10.5, November 2018 7/18/2022, 7:55 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins 1-1 -1-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 23,999 0.55 0.95 0.95 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i in/ 9 Calculate the Post -Development peak discharge (CiPeak) Cipeak 0.97 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) 1,300 ft, V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) Vrr 1,131 ft, 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 130 ft' Primary Treatment/StorageBasin V 1,170 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,300 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin J.xlsm Version 10.5, November 2018 7/18/2022, 7:56 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin K-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 0 9 Calculate the Post -Development peak discharge (QPeak) i Clpeak 1.85 0.33 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 448 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 390 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 45 ft' Primary Treatment/StorageBasin V 403 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 448 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 8,269 0.19 0.95 0.95 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin K.xlsm Version 10.5, November 2018 7/18/2022, 7:57 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin K-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 9 Calculate the Post -Development peak discharge (QPeak) Q,A i= in/hr 0.46 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 614 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) Vrr 534 ft, 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 61 ft' Primary Treatment/StorageBasin V 553 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 614 W flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 10,895 4,244 0.35 0.95 0.10 0.71 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin K.xlsm Version 10.5, November 2018 7/18/2022, 7:57 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins K-1 - K-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 5 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.79 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,062 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 924 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 106 ft' Primary Treatment/StorageBasin V 956 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,062 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 19,164 4,244 0.54 0.95 0.10 0.80 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin K.xlsm Version 10.5, November 2018 7/18/2022, 7:57 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin L-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (ClPeak) Clpeak 0.37 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 502 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 436 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 50 ft' Primary Treatment/StorageBasin V 451 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 502 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 9,073 1,771 0.25 0.95 0.10 0.81 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin L.xlsm Version 10.5, November 2018 7/18/2022, 7:58 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin L-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 1.85 0.37 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 492 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 428 ft, 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 49 ft' Primary Treatment/StorageBasin V 443 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 492 W flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 8,816 2,582 0.26 0.95 0.10 0.76 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.l0-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin L.xlsm Version 10.5, November 2018 7/18/2022, 7:58 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins L-1 - L-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 5 0.74 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 994 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 864 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 99 ft' Primary Treatment/StorageBasin V 895 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 994 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 17,889 4,353 0.51 0.95 0.10 0.78 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin L.xlsm Version 10.5, November 2018 7/18/2022, 7:59 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin M-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (ClPeak) Clpeak 0.34 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 460 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 400 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 46 ft' Primary Treatment/StorageBasin V 414 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 460 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 8,216 2,677 0.25 0.95 0.10 0.74 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin M.xlsm Version 10.5, November 2018 7/18/2022, 8:00 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin M-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate [10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 9 Calculate the Post -Development peak discharge (QPeak) i Qpe,k 1.85 0.37 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 495 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V„ 431 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 5o ft' Primary Treatment/Storage Basin V 446 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 495 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 8,862 2,676 0.26 0.95 0.10 0.75 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin M.xlsm Version 10.5, November 2018 7/18/2022, 8:00 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins M-1 - M-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 5 0.71 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 956 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 831 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 96 ft' Primary Treatment/StorageBasin V 860 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 956 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 17,078 5,353 0.51 0.95 0.10 0.75 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin M.xlsm Version 10.5, November 2018 7/18/2022, 8:00 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin N-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Clpeak 0.49 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 656 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 571 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 66 ft' Primary Treatment/StorageBasin V 591 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 656 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 11,663 4,288 0.37 0.95 0.10 0.72 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin N.xlsm Version 10.5, November 2018 7/18/2022, 8:01 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin N-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 5 0.49 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 658 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 573 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 66 ft' Primary Treatment/StorageBasin V 593 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 658 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 11,700 4,308 0.37 0.95 0.10 0.72 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin N.xlsm Version 10.5, November 2018 7/18/2022, 8:01 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins N-1- N-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate [10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpe,k 0.98 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,315 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V„ 1,143 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 131 ft, V 1,183 ft' V 1,315 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 23,363 8,596 0.73 0.95 0.10 0.72 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.l0-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin N.xlsm Version 10.5, November 2018 7/18/2022, 8:02 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin 0-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (ClPeak) Clpeak 0.73 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 974 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 847 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 97 ft' Primary Treatment/StorageBasin V 877 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 974 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 17,268 6,755 0.55 0.95 0.10 0.71 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin O.xlsm Version 10.5, November 2018 7/18/2022, 8:02 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin 0-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate j10 Miami 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 9 Calculate the Post -Development peak discharge (CiPeak) Q,A 1.85 0.72 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 972 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V„ 845 ft, 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 97 ft' Primary Treatment/StorageBasin V 875 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 972 W flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 17,231 6,734 0.55 0.95 0.10 0.71 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.l0-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin O.xlsm Version 10.5, November 2018 7/18/2022, 8:03 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins 0-1- 0-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc i 5 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Q,A 1.45 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,946 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 1,692 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 195 ft' V 1,751 ft' V 1,946 ft' rlirk to Ghnw Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 34,499 13,489 1.10 0.95 0.10 0.71 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin O.xlsm Version 10.5, November 2018 7/18/2022, 8:03 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin P-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (CiPeak) Clpeak 0.49 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 659 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 573 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 66 ft' Primary Treatment/StorageBasin V 593 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 659 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 11,718 4,292 0.37 0.95 0.10 0.72 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin P.xlsm Version 10.5, November 2018 7/18/2022, 8:04 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin P-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 5 0.45 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 605 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 526 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 60 ft' Primary Treatment/StorageBasin V 544 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 605 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 10,919 2,327 0.30 0.95 0.10 0.80 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin P.xlsm Version 10.5, November 2018 7/18/2022, 8:04 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins P-1- P-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 25 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate [10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc i 1.85 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpe,k 0.94 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,264 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 1,099 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 126 ft, V 1,138 ft' V 1,264 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 22,637 6,619 0.67 0.95 0.10 0.76 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.l0-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin P.xlsm Version 10.5, November 2018 7/18/2022, 8:04 PM POST -DEVELOPMENT 100-YEAR CALCULATIONS ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin A-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 16,598 4,936 0.49 0.95 0.10 0.76 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 0 i 2.58 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.96 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,290 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 806 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 129 ft' Primary Treatment/StorageBasin V 1,161 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,290 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin A.xlsm Version 10.5, November 2018 7/18/2022, 6:08 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin A-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 16,877 4,935 0.50 0.95 0.10 0.76 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (QPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) QPeak 0.98 cfs V 1,311 ft ■ 95th 0.60 in Vrr 820 ft, cfs V 131 ft, V 1,180 W V 1,311 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin A.Asm Version 10.5, November 2018 7/18/2022, 6:08 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins A-1- A-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate [10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc i 2.58 in/hr 9 Calculate the Post -Development peak discharge (CiPeak) Qpe,k 1.94 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 2,601 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 1,626 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 260 ft, V 2,341 ft' V 2,601 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 33,475 9,871 1.00 0.95 0.10 0.76 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin A.xlsm Version 10.5, November 2018 7/18/2022, 6:09 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin B-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 15,350 4,705 0.46 0.95 0.10 0.75 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 0 i 2.58 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Clpeak 0.89 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,194 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 746 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 119 ft' Primary Treatment/StorageBasin V 1,075 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,194 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin B.xlsm Version 10.5, November 2018 7/18/2022, 6:09 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin B-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate [10 Mir, 8 Determine the average rainfall intensity (i) from OF Curve based on Tc i 2.58 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpe,k 0.84 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,129 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V„ 706 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 113 ft, V 1,016 ft' V 1,129 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 14,525 4,337 0.43 0.95 0.10 0.75 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin B.xlsm Version 10.5, November 2018 7/18/2022, 6:09 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins B-1- B-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 29,875 9,042 0.89 0.95 0.10 0.75 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (QPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) QPeak 1.73 cfs V 2,323 ft 95th 0.60 in V„ 1,452 ft, cfs V 232 ft, V 2,091 W V 2,323 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin B.xlsm Version 10.5, November 2018 7/18/2022, 6:10 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin C-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 0 i 2.58 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Clpeak 0.44 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 593 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 371 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 59 ft' Primary Treatment/StorageBasin V 534 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 593 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 7,679 1,824 0.22 0.95 0.10 0.79 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin C.xlsm Version 10.5, November 2018 7/18/2022, 6:22 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin C-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 2.58 0.30 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 405 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 253 ft, 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 40 ft' Primary Treatment/StorageBasin V 364 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 405 W flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 5,199 1,642 0.16 0.95 0.10 0.75 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.l0-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin C.xlsm Version 10.5, November 2018 7/18/2022, 6:22 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins C-1- C-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 9 Calculate the Post -Development peak discharge (CiPeak) Cipeak 2.58 0.75 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) 998 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) Vrr 624 ft, 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 100 ft' Primary Treatment/StorageBasin V 898 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 998 W rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 12,878 3,466 0.38 0.95 0.10 0.77 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.l0-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin C.xlsm Version 10.5, November 2018 7/18/2022, 6:23 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin D-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 21,316 6,130 0.63 0.95 0.10 0.76 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 0 i 2.58 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 1.24 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,655 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 1,035 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 166 ft' Primary Treatment/StorageBasin V 1,490 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,655 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin D.xlsm Version 10.5, November 2018 7/18/2022, 6:23 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin D-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc g in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 1.21 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,620 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 1,012 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 162 ft' V 1,458 ft' V 1,620 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 20,885 5,743 0.61 0.95 0.10 0.77 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin D.xlsm Version 10.5, November 2018 7/18/2022, 6:23 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins D-1- D-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 42,201 11,873 1.24 0.95 0.10 0.76 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (CiPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) 4peak 2.44 cfs V 3,275 ft ■ 95th 0.60 in Vrr 2,047 ft, cfs V 327 ft, V 2,947 W V 3,275 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin D.xlsm Version 10.5, November 2018 7/18/2022, 6:23 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin E-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 5,594 1,274 0.16 0.95 0.10 0.79 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 2.58 in/ 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.32 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V W V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 270 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 43 ft' Primary Treatment/StorageBasin V 0 389 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 432 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.3, Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin E.xlsm Version 10.5, November 2018 7/18/2022, 6:24 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin E-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 6,771 1,234 0.18 0.95 0.10 0.82 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User Calculate hoMin. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 2.58 in/ 9 Calculate the Post -Development peak discharge (QPeak) 0.39 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) 520 ft' V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 325 ft. 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 52 ft' Primary Treatment/StorageBasin V 468 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 520 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin E.xlsm Version 10.5, November 2018 7/18/2022, 6:24 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins E-1- E-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i in/ 9 Calculate the Post -Development peak discharge (CiPeak) Cipeak 0.71 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) 952 ft' V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) Vrr 595 ft, 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 95 ft' Primary Treatment/StorageBasin V 857 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 952 W rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 12,365 2,508 0.34 0.95 0.10 0.81 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin E.xlsm Version 10.5, November 2018 7/18/2022, 6:25 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin F-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 18,760 2,570 0.49 0.95 0.10 0.85 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 2.58 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Clpeak 1.07 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,434 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 896 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 143 ft' Primary Treatment/StorageBasin V 1,291 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,434 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin F.xlsm Version 10.5, November 2018 7/18/2022, 6:25 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin F-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 17,224 2,611 0.46 0.95 0.10 0.84 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate (10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (QPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) QPeak 0.98 cfs V 1,319 ft 95th 0.60 in V,r 824 ft, cfs V 132 ft, V 1,187 W V 1,319 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin F.xlsm Version 10.5, November 2018 7/18/2022, 6:25 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins F-1- F-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 35,984 5,181 0.95 0.95 0.10 0.84 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate (10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 2.58 in/ 9 Calculate the Post -Development peak discharge (QPeak) 2.06 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) 2,753 ft' V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V„ 1,721 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 275 ft' Primary Treatment/StorageBasin V 2,478 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 2,753 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin F.xlsm Version 10.5, November 2018 7/18/2022, 6:26 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin G-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 2.58 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.52 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 696 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 435 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 70 ft' Primary Treatment/StorageBasin V 627 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 696 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 9,102 1,273 0.24 0.95 0.10 0.85 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin G.xlsm Version 10.5, November 2018 7/18/2022, 6:26 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin G-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate [10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc 9 Calculate the Post -Development peak discharge (CiPeak) i Qpe,k 2.58 0.56 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 744 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V„ 465 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 74 ft' Primary Treatment/StorageBasin V 670 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 744 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 9,760 1,107 0.25 0.95 0.10 0.86 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin G.xlsm Version 10.5, November 2018 7/18/2022, 6:26 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins G-1- G-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 18,862 2,380 0.49 0.95 0.10 0.85 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate N MIn.------------ 1 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (QPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) QPeak 1.08 cfs V 1,441 ft 95th 0.60 in Vrr 900 ft, cfs V 144 ft, V 1,296 W V 1,441 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin G.xlsm Version 10.5, November 2018 7/18/2022, 6:26 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin H-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 17,388 1,903 0.44 0.95 0.10 0.87 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 2.58 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.99 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,326 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 829 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 133 ft' Primary Treatment/StorageBasin V 1,193 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,326 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin H.xlsm Version 10.5, November 2018 7/18/2022, 7:08 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin H-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 20,087 2,744 0.52 0.95 0.10 0.85 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate (10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (CiPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) Qpeak 1.15 cfs V 1,536 ft 95th 0.60 in V,r 960 ft, cfs V 154 ft, V 1,382 W V 1,536 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin H.xlsm Version 10.5, November 2018 7/18/2022, 7:09 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins H-1- H-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 37,475 4,647 0.97 0.95 0.10 0.86 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate (10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (CiPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) Q,A 2.14 cfs V 2,861 ft 95th 0.60 in Vrr 1,788 ft, cfs V 286 ft, V 2,575 W V 2,861 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin H.xlsm Version 10.5, November 2018 7/18/2022, 7:09 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin 1-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 1 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 2.58 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.52 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 692 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 433 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 69 ft' Primary Treatment/StorageBasin V 623 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 692 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 9,184 0.21 0.95 0.95 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin I.xlsm Version 10.5, November 2018 7/18/2022, 7:09 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin 1-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 10,455 0.24 0.95 0.95 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 0 i 2.58 in/ 9 Calculate the Post -Development peak discharge (CiPeak) Clpeak 0.59 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V W V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 493 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 79 ft' Primary Treatment/StorageBasin V 0 709 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 788 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.3, Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin J.xlsm Version 10.5, November 2018 7/18/2022, 7:10 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin J-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate (10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc i g in/hr 9 Calculate the Post -Development peak discharge (QPeak) Q,A 0.76 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,021 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 638 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 102 ft' Primary Treatment/StorageBasin V 919 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,021 ft' rlirk to Ghnw Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 13,544 0.31 0.95 0.95 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin J.xlsm Version 10.5, November 2018 7/18/2022, 7:10 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins J-1- J-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 23,999 0.55 0.95 0.95 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (QPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) Q,A 1.3S cfs V 1,809 ft 95th 0.60 in V,r 1,131 ft, cfs V 181 ft, V 1,628 W V 1,809 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin J.xlsm Version 10.5, November 2018 7/18/2022, 7:11 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin K-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 2.58 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Clpeak 0.47 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 623 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 390 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 62 ft' Primary Treatment/StorageBasin V 561 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 623 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 8,269 0.19 0.95 0.95 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin K.xlsm Version 10.5, November 2018 7/18/2022, 7:12 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin K-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 10,895 4,244 0.35 0.95 0.10 0.71 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 2.58 in/ 9 Calculate the Post -Development peak discharge (CiPeak) 0.64 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) 855 ft' V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) Vrr 534 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 85 ft' Primary Treatment/StorageBasin V 769 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 855 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin K.xlsm Version 10.5, November 2018 7/18/2022, 7:12 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins K-1- K-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 19,164 4,244 0.54 0.95 0.10 0.80 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (CiPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) Q,A 1.10 cfs V 1,478 ft 95th 0.60 in V,r 924 ft, cfs V 148 ft, V 1,330 W V 1,478 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin K.xlsm Version 10.5, November 2018 7/18/2022, 7:13 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin L-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 9,073 1,771 0.25 0.95 0.10 0.81 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 2.58 in/ 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 0.52 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V W V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 436 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 70 ft' Primary Treatment/StorageBasin V 0 628 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 698 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.3, Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin L.xlsm Version 10.5, November 2018 7/18/2022, 7:13 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin L-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 8,816 2,582 0.26 0.95 0.10 0.76 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 2.58 in/ 9 Calculate the Post -Development peak discharge (QPeak) 0.51 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) 685 ft' V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) Vrr 428 ft. 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 68 ft' Primary Treatment/StorageBasin V 616 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 685 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin L.xlsm Version 10.5, November 2018 7/18/2022, 7:14 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins L-1 - L-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate [10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc i 2.58 in/hr 9 Calculate the Post -Development peak discharge (CiPeak) Qpe,k 1.03 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,383 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 864 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 138 ft, V 1,245 ft' V 1,383 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 17,889 4,353 0.51 0.95 0.10 0.78 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin L.xlsm Version 10.5, November 2018 7/18/2022, 7:14 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin M-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate [10 Min. - 8 Determine the average rainfall intensity (i) from ICIF Curve based on Tc 9 Calculate the Post -Development peak discharge (QPeak) i Qpeak 2.58 0.48 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 640 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 400 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 64 ft' Primary Treatment/StorageBasin V 576 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 640 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 8,216 2,677 0.25 0.95 0.10 0.74 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin M.xlsm Version 10.5, November 2018 7/18/2022, 7:15 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin M-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 8,862 2,676 0.26 0.95 0.10 0.75 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 2.58 in/ 9 Calculate the Post -Development peak discharge (QPeak) 0.51 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) 689 ft' V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) Vrr 431 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 69 ft' Primary Treatment/StorageBasin V 620 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 689 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin M.xlsm Version 10.5, November 2018 7/18/2022, 7:15 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins M-1- M-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 17,078 5,353 0.51 0.95 0.10 0.75 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (QPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) Q,A 0.99 cfs V 1,330 ft 95th 0.60 in V,r 831 ft, cfs V 133 ft, V 1,197 W V 1,330 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin M.xlsm Version 10.5, November 2018 7/18/2022, 7:15 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin N-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 2.58 in/hr 9 Calculate the Post -Development peak discharge (ClPeak) Clpeak 0.68 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 913 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 571 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 91 ft' Primary Treatment/StorageBasin V 822 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 913 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 11,663 4,288 0.37 0.95 0.10 0.72 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin N.xlsm Version 10.5, November 2018 7/18/2022, 7:16 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin N-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate N MIn.------------ 1 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 9 Calculate the Post -Development peak discharge (QPeak) QPeak 2.58 0.68 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 916 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) Vrr 573 ft, 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 92 ft' Primary Treatment/StorageBasin V 824 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 916 W rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 11,700 4,308 0.37 0.95 0.10 0.72 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.l0-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin N.xlsm Version 10.5, November 2018 7/18/2022, 7:16 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins N-1- N-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 23,363 8,596 0.73 0.95 0.10 0.72 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (QPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) Q,A 1.37 cfs V 1,829 ft 95th 0.60 in V,r 1,143 ft, cfs V 183 ft, V 1,646 W V 1,829 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin N.xlsm Version 10.5, November 2018 7/18/2022, 7:17 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin 0-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avl Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 17,268 6,755 0.55 0.95 0.10 0.71 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 2.58 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Clpeak 1.01 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,355 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 847 ft' 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 136 ft' Primary Treatment/StorageBasin V 1,220 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,355 ft' Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin O.xlsm Version 10.5, November 2018 7/18/2022, 7:17 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin 0-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 17,231 6,734 0.55 0.95 0.10 0.71 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate j10 Miami 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (QPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) QPeak 1.01 cfs V 1,352 ft 95th 0.60 in Vrr 845 ft, cfs V 135 ft, V 1,217 W V 1,352 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin O.xlsm Version 10.5, November 2018 7/18/2022, 7:18 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins 0-1- 0-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Av( flick to Ghrmu Mnra 4ihhacin< n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 34,499 13,489 1.10 0.95 0.10 0.71 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on 9 Calculate the Post -Development peak discharge (CiPeak) 10 Calculate total runoff vol (V) (for sizing primary storage) V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) Q,A 2.02 cfs V 2,707 ft 95th 0.60 in V,r 1,692 ft, cfs V 271 ft, V 2,437 W V 2,707 W Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds NMI! Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin O.xlsm Version 10.5, November 2018 7/18/2022, 7:18 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1 - Basin P-1 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities (25 max) 3 Click to Show More Suhbasins n 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user Calculate [10 Min. - 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 2.58 in/hr 9 Calculate the Post -Development peak discharge (QPeak) Clpeak 0.68 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 917 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percent! le=0.60-in x Area x C) Vr, 573 ft.12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 92 ft' Primary Treatment/StorageBasin V 826 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 917 ft' Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 30 11,718 4,292 0.37 0.95 0.10 0.72 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 0.07 0.11 0 Average: 2-6% 0.13 0.12 0.15 0 Steep:>6% 0. 0.18 0.23 0 Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin P.xlsm Version 10.5, November 2018 7/18/2022, 7:21 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Peak Discharge Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin P-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min user calculate j10 Min. 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 2.58 0.63 in/hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 841 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) Vrr 526 ft, 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 84 ft' Primary Treatment/StorageBasin V 757 W Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 841 W rlirk to Ghnw Mnra 4ihhacin n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 10,919 2,327 0.30 0.95 0.10 0.80 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.l0-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C 0 Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 O Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin P.xlsm Version 10.5, November 2018 7/18/2022, 7:23 PM ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins P-1- P-2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 min User calculate [10 Min. 8 Determine the average rainfall intensity (i) from OF Curve based on Tc i 2.58 in/hr 9 Calculate the Post -Development peak discharge (CiPeak) Qpe,k 1.31 cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,759 ft V = Ci(Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V,r 1,099 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay Primary Treatment/Storage Basin Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 176 ft, V 1,583 ft' V 1,759 ft' rlirk to Ghn , Mnrc Ci,hha inc n Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 Subbasin 3 4 5 Subbasin 6 7 8 9 10 22,637 6,619 0.67 0.95 0.10 0.76 Estimated Runoff Coefficients for Various Surfac Type of Surface Runoff Coefficients " Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries o.l0-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 Of 0.11 0 Average: 2-6% 0.09 0.12 0.15 0 Steep:>6% 0.13 0.18 0.23 O Adapted from ASCE P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin P.xlsm Version 10.5, November 2018 7/18/2022, 7:24 PM SEEPAGE BED CALCULATIONS ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak Q,W tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins A-1- A-2, SB #1 2 Enter number of Seepage Beds (25 max) 1 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.76 Unkto: 0_y1 QV TR55 5 Area A (Acres) 1.00 acres _ 6 Approved discharge rate (if applicable) 0.00 cfs 7 Is Seepage Bed in Common Lot? No V 3,252 ft3 25%Sediment 8 Infiltartion Volume in the First Hour V 550 9 Set Total Design Width of All Drain Rock W 13.0 ft 10 Set Total Design Depth of All Drain Rock D 8.0 ft Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 8.00 in/hr 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 18 in 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs in 15 Calculate Design Length L 65 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 65 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 65 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ft2 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90% volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin A.xlsm 7/18/2022, 9:08 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins B-1- 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No V 8 Infiltartion Volume in the First Hour V 9 Set Total Design Width of All Drain Rock W 10 Set Total Design Depth of All Drain Rock D Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs -2, SIB #2 1 100 0.75 0.89 acres 0.00 cfs 2,904 492 13.0 ft 8.0 ft 0.4 8.00 in/hr 18 in in Unkto: Qy1 QV TR55 ft3 25% Sediment 15 Calculate Design Length L 58 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 58 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 58 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin B.xlsm 7/18/2022, 9:09 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak Q,V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins C-1- C-2, SB #3 rncer numoer or seepage peas �zn maxi i 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.77 Unkto: 0_V1 QV TR55 5 Area A (Acres) 0.38 acres _ 6 Approved discharge rate (if applicable) 0.00 cfs 7 Is Seepage Bed in Common Lot? No V 1,248 ft3 25%Sediment 8 Infiltartion Volume in the First Hour V 211 9 Set Total Design Width of All Drain Rock W 13.0 ft 10 Set Total Design Depth of All Drain Rock D 8.0 ft Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 8.00 in/hr 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 18 in 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs in 15 Calculate Design Length L 25 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 25 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 25 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) upnonai morage Lnamoers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ft2 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90% volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin C.xlsm 7/18/2022, 9:09 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins D-1- 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No V 8 Infiltartion Volume in the First Hour V 9 Set Total Design Width of All Drain Rock W 10 Set Total Design Depth of All Drain Rock D Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs 1-2, SIB q4 1 100 0.76 1.24 acres 0.00 cfs 4,094 693 13.0 ft 8.0 ft 0.4 8.00 in/hr 18 in in Unkto: Qy1 QV TR55 ft3 25% Sediment 15 Calculate Design Length L 82 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 82 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 82 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin D.xlsm 7/18/2022, 9:10 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins E-1- 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No V 8 Infiltartion Volume in the First Hour V 9 Set Total Design Width of All Drain Rock W 10 Set Total Design Depth of All Drain Rock D Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs -2, SIB #5 1 100 0.81 0.34 acres 0.00 cfs 1,190 201 11.5 ft 8.0 ft 0.4 8.00 in/hr 18 in in Unkto: Qy1 QV TR55 ft3 25% Sediment 15 Calculate Design Length L 27 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 27 ft 17 Variable Infiltration Window W SWW 11.5 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 27 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin E.xlsm 7/18/2022, 9:11 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins F-1- F-2, SB #6 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No V 8 Infiltartion Volume in the First Hour V 9 Set Total Design Width of All Drain Rock W 10 Set Total Design Depth of All Drain Rock D Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs 0.84 0.95 acres 0.00 cfs 3,442 582 13.0 ft 8.0 ft 0.4 8.00 in/hr 18 in in 1 Unkto: Qy1 QV TR55 ft3 25% Sediment 15 Calculate Design Length L 69 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 69 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 69 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin F.xlsm 7/18/2022, 9:11 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins G-1- 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No V 8 Infiltartion Volume in the First Hour V 9 Set Total Design Width of All Drain Rock W 10 Set Total Design Depth of All Drain Rock D Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs i-2, SB #7 1 100 0.85 0.49 acres 0.00 cfs 1,801 305 13.0 ft 8.0 ft 0.4 8.00 in/hr 18 in in Linkto: 0_V1 QV TR55 ft3 25% Sediment 15 Calculate Design Length L 36 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 36 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 36 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin G.xlsm 7/18/2022, 9:12 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins H-1- 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No V 8 Infiltartion Volume in the First Hour V 9 Set Total Design Width of All Drain Rock W 10 Set Total Design Depth of All Drain Rock D Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs 1-2, SB #8 1 100 0.86 0.97 acres 0.00 cfs 3,577 605 13.0 ft 8.0 ft 0.4 8.00 in/hr 18 in in Unkto: Qy1 QV TR55 ft3 25% Sediment 15 Calculate Design Length L 71 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 71 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 71 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin H.xlsm 7/18/2022, 9:12 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basin 1-1, SB #9 2 Enter number of Seepage Beds (25 max) 1 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.95 Unkto: Q'V QV TR55 5 Area A (Acres) 0.21 acres 6 Approved discharge rate (if applicable) 0.00 cfs 7 Is Seepage Bed in Common Lot? No V 865 ft3 25%Sediment 8 Infiltartion Volume in the First Hour V 150 9 Set Total Design Width of All Drain Rock W 8.0 ft 10 Set Total Design Depth of All Drain Rock D 7.5 ft Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 8.00 in/hr 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 18 in 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs in 15 Calculate Design Length L 30 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 30 ft 17 Variable Infiltration Window W SWW 8.0 ft 18 Time to Drain 4.9 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 30 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin I.xlsm 7/18/2022, 9:12 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins J-1- J-2, SB #10 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No V 8 Infiltartion Volume in the First Hour V 9 Set Total Design Width of All Drain Rock W 10 Set Total Design Depth of All Drain Rock D Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs 0.95 0.55 acres 0.00 cfs 2,261 383 8.0 ft 8.0 ft 0.4 8.00 in/hr 18 in in 1 Unkto: Qy1 QV TR55 ft3 25%Sediment 15 Calculate Design Length L 73 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 73 ft 17 Variable Infiltration Window W SWW 8.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 73 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc It 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin J.xlsm 7/18/2022, 9:13 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins K-1- 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No V 8 Infiltartion Volume in the First Hour V 9 Set Total Design Width of All Drain Rock W 10 Set Total Design Depth of All Drain Rock D Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs -2, SB #11 1 100 0.80 0.54 acres 0.00 cfs 1,848 313 13.0 ft 8.0 ft 0.4 8.00 in/hr 18 in in Unkto: QV QV2 [QV3� QV TR55 ft3 25% Sediment 15 Calculate Design Length L 37 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 37 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 37 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin K.xlsm 7/18/2022, 9:13 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins L-1- L-2, SB #12 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No V 8 Infiltartion Volume in the First Hour V 9 Set Total Design Width of All Drain Rock W 10 Set Total Design Depth of All Drain Rock D Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs 0.78 0.51 acres 0.00 cfs 1,729 293 13.0 ft 8.0 ft 0.4 8.00 in/hr 18 in in 1 Unkto: Qv QV2 [QV3� QV TR55 ft3 25% Sediment 15 Calculate Design Length L 35 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 35 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 35 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin L.xlsm 7/18/2022, 9:14 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins M-1- 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No V 8 Infiltartion Volume in the First Hour V 9 Set Total Design Width of All Drain Rock W 10 Set Total Design Depth of All Drain Rock D Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs Vl-2, SB #13 1 100 0.75 0.51 acres 0.00 cfs 1,662 281 13.0 ft 8.0 ft 0.4 8.00 in/hr 18 in in Unkto: QV QV2 [QV3� QV TR55 ft3 25% Sediment 15 Calculate Design Length L 33 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 33 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 33 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft' 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin M.xlsm 7/18/2022, 9:14 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins N-1- 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No V 8 Infiltartion Volume in the First Hour V 9 Set Total Design Width of All Drain Rock W 10 Set Total Design Depth of All Drain Rock D Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs 1-2, SB #14 1 100 0.72 0.73 acres 0.00 cfs 2,286 387 13.0 ft 8.0 ft 0.4 8.00 in/hr 18 in in Unkto: QV QV2 [QV3� QV TR55 ft3 25% Sediment 15 Calculate Design Length L 46 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 46 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 46 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin N.xlsm 7/18/2022, 9:15 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak %V" tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins 0-1- 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No V 8 Infiltartion Volume in the First Hour V 9 Set Total Design Width of All Drain Rock W 10 Set Total Design Depth of All Drain Rock D Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs )-2, SB #15 1 100 0.71 1.10 acres 0.00 cfs 3,384 573 13.0 ft 8.0 ft 0.4 8.00 in/hr 18 in in Unkto: QV QV2 [QV3� QV TR55 ft3 25% Sediment 15 Calculate Design Length L 68 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 68 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 68 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin O.xlsm 7/18/2022, 9:15 PM Version 10.0, May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the "Peak Q,W tab Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Pollard Subdivision No. 1- Basins P-1- P-2, SB #16 rncer numoer or seepage peas izn maxi i 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.76 Link to: QV 5 Area A (Acres) 0.67 acres [QV3� 6 Approved discharge rate (if applicable) 0.00 cfs QV TR55 7 Is Seepage Bed in Common Lot? No V 2,198 ft3 25%Sediment 8 Infiltartion Volume in the First Hour V 372 9 Set Total Design Width of All Drain Rock W 13.0 ft 10 Set Total Design Depth of All Drain Rock D 8.0 ft Rock Only, Do Not Include Filter Sand Depth or Cover 11 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2" drain rock and 3/4" Chips 12 Design Infiltration Rate (8 in/hr max) Perc 8.00 in/hr 13 Size of WQ Perf Pipe (Perf 1800) Dia pipe 18 in 14 Size of Overflow Perf Pipe (Perfs 3600), READ if Q100>3.3 cfs in 15 Calculate Design Length L 44 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 44 ft 17 Variable Infiltration Window W SWW 13.0 ft 18 Time to Drain 5.2 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 44 ft 20 Perf Pipe Checks. Qperf >= Qpeak; where Qperf=CdxAxV(2xgxH) upnonai morage Lnamoers Note: This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ft2 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90% volume in 48-hours minimum P:\21-240\Documents\Reports\Storm Drainage\Calcs\21-240 Storm Drain Calc Basin P.xlsm 7/18/2022, 9:16 PM Version 10.0, May 2018 APPENDIX D - GEOTECHNICAL ENGINEERING REPORT MATERIALS TESTING £r INSPECTION ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections GEOTECHNICAL ENGINEERING REPORT of Pollard lane Realignment Pollard Lane & Chinden Boulevard Meridian, ID Prepared for: Brighton Corporation 12601 West Explore Drive, Suite 200 Boise, ID 83713 MTI File Number B161073g 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mtiCcDmti-id.com MATERIALS TESTI NG & INSPECTION C] Environmental Services ❑ Geotechnical Engineering Mr. Jon Wardle Brighton Corporation 12601 West Explore Drive, Suite 200 Boise, ID 83713 208-378-4000 Dear Mr. Wardle: ❑ Construction Materials Testing 31 August 2016 Page # 1 of 26 bl6l073g_geotech.docx ❑ Special I Re: Geotechnical Engineering Report Pollard Lane Realignment Pollard Lane & Chinden Boulevard Meridian, ID In compliance with your instructions, MTI has conducted a soils exploration and pavement evaluation for the above referenced development. Fieldwork for this investigation was conducted on 19 August 2016. Data have been analyzed to evaluate pertinent geotechnical conditions. Results of this investigation, together with our recommendations, are to be found in the following report. We have provided a PDF copy for your review and distribution. Often, questions arise concerning soil conditions because of design and construction details that occur on a project. MTI would be pleased to continue our role as geotechnical engineers during project implementation. Additionally, MTI can provide materials testing and special inspection services during construction of this project. If you will advise us of the appropriate time to discuss these engineering services, we will meet with you at your convenience. MTI appreciates this opportunity to be of service to you and looks forward to working with you in the future. If you have questions, please call (208) 376-4748. Respectfully Submitted, Materials Testing & Inspection, Inc. J.GG�.c i%vtM' Jacob Schlador, E.I.T. Staff Engineer Reviewed by: Monica Saci?Yles, P Geotechnical Eneir Reviewed by: Eli abeth Brown, P.E. Geotechnical Engineer s\CENSF N 14919 FOF10 �y �ti��q 2791 S Victory View Way • Boise, U 83709 • (208) 376-4748 • Fax (208) 322-6515 _ie eis www.mti-id.com • mti(d)mti-id.com Teonroa•nsoecto.,„,n �.. MATERIALS 31 August 2016 TESTI NG & Page # 2 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections TABLE OF CONTENTS INTRODUCTION...............................................................................................................................................................3 ProjectDescription.................................................................................................................................................3 Authorization..........................................................................................................................................................3 Purpose...................................................................................................................................................................3 Scopeof Investigation............................................................................................................................................3 Warranty and Limiting Conditions.........................................................................................................................4 SITEDESCRIPTION..........................................................................................................................................................5 SiteAccess..............................................................................................................................................................5 RegionalGeology...................................................................................................................................................5 General Site Characteristics....................................................................................................................................5 Regional Site Climatology and Geochemistry ........................................................................................................6 SOILSEXPLORATION......................................................................................................................................................6 Exploration and Sampling Procedures....................................................................................................................6 LaboratoryTesting Program...................................................................................................................................6 Soiland Sediment Profile.......................................................................................................................................7 VolatileOrganic Scan.............................................................................................................................................7 SITEHYDROLOGY...........................................................................................................................................................7 Groundwater...........................................................................................................................................................7 SoilInfiltration Rates..............................................................................................................................................8 PAVEMENT DISCUSSION AND RECOMMENDATIONS........................................................................................................8 Recommended Pavement Sections.........................................................................................................................8 FlexiblePavement Section.....................................................................................................................................9 Common Pavement Section Construction Issues...................................................................................................9 CONSTRUCTION CONSIDERATIONS...............................................................................................................................10 Earthwork.............................................................................................................................................................10 DryWeather.........................................................................................................................................................11 WetWeather.........................................................................................................................................................11 SoftSubgrade Soils..............................................................................................................................................11 FrozenSubgrade Soils..........................................................................................................................................12 StructuralFill........................................................................................................................................................12 Excavations...........................................................................................................................................................13 GroundwaterControl............................................................................................................................................13 GENERALCOMMENTS..................................................................................................................................................14 REFERENCES.................................................................................................................................................................15 APPENDICES.................................................................................................................................................................16 AcronymList........................................................................................................................................................16 Geotechnical General Notes.................................................................................................................................17 Geotechnical Investigation Test Pit Log...............................................................................................................18 Gravel Equivalent Method — Pavement Thickness Design Procedures................................................................23 R-Value Laboratory Test Data..............................................................................................................................24 Plate1: Vicinity Map............................................................................................................................................25 Plate2: Site Map...................................................................................................................................................26 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 3 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections INTRODUCTION This report presents results of a geotechnical investigation and analysis in support of data utilized in design of pavements as defined in the Idaho Standard for Public Works Construction. Information in support of groundwater and stormwater issues pertinent to the practice of Civil Engineering is included. Observations and recommendations relevant to the earthwork phase of the project are also presented. Revisions in plans or drawings for the proposed development from those enumerated in this report should be brought to the attention of the soils engineer to determine whether changes in the provided recommendations are required. Deviations from noted subsurface conditions, if encountered during construction, should also be brought to the attention of the soils engineer. Project Description The proposed development is northwest of the City of Meridian, Ada County, ID, and occupies a portion of the SE'/4SW'/a and SW'/4SE'/a of Section 21, Township 4 North, Range 1 West, Boise Meridian. This project will consist of relocating a portion of Pollard Lane to align with Levi Lane on the south side of Chinden Boulevard. The proposed roadway section will be roughly 0.35 mile in length. At this time, barrow ditches are planned for the sides of the rural roadway. Assumptions have been made for traffic loading of pavements. Retaining walls are not anticipated as part of the project. MTI has not been informed of the proposed grading plan. Authorization Authorization to perform this exploration and analysis was given in the form of a written authorization to proceed from Mr. Jon Wardle of Brighton Corporation to Monica Saculles of Materials Testing and Inspection, Inc. (MTI), on 10 August 2016. Said authorization is subject to terms, conditions, and limitations described in the Professional Services Contract entered into between Brighton Corporation and MTI. Our scope of services for the proposed development has been provided in our proposal dated 10 August 2016 and repeated below. Purpose The purpose of this Geotechnical Engineering Report is to determine various soil profile components and their engineering characteristics for use by either design engineers or architects in: • Preparing site drainage designs • Indicating issues pertaining to earthwork construction • Preparing rural roadway pavement section design requirements Scope of Investigation The scope of this investigation included review of geologic literature and existing available geotechnical studies of the area, visual site reconnaissance of the immediate site, subsurface exploration of the site, field and laboratory testing of materials collected, and engineering analysis and evaluation of pavement materials. Our scope of work did not include foundation recommendations. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 4 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections Warranty and Limiting Conditions MTI warrants that findings and conclusions contained herein have been formulated in accordance with generally accepted professional engineering practice in the fields of foundation engineering, soil mechanics, and engineering geology only for the site and project described in this report. These engineering methods have been developed to provide the client with information regarding apparent or potential engineering conditions relating to the site within the scope cited above and are necessarily limited to conditions observed at the time of the site visit and research. Field observations and research reported herein are considered sufficient in detail and scope to form a reasonable basis for the purposes cited above. Exclusive Use This report was prepared for exclusive use of the property owner(s), at the time of the report, and their retained design consultants ("Client"). Conclusions and recommendations presented in this report are based on the agreed -upon scope of work outlined in this report together with the Contract for Professional Services between the Client and Materials Testing and Inspection, Inc. ("Consultant"). Use or misuse of this report, or reliance upon findings hereof, by parties other than the Client is at their own risk. Neither Client nor Consultant make representation of warranty to such other parties as to accuracy or completeness of this report or suitability of its use by such other parties for purposes whatsoever, known or unknown, to Client or Consultant. Neither Client nor Consultant shall have liability to indemnify or hold harmless third parties for losses incurred by actual or purported use or misuse of this report. No other warranties are implied or expressed. Report Recommendations are Limited and Subiect to Misinterpretation There is a distinct possibility that conditions may exist that could not be identified within the scope of the investigation or that were not apparent during our site investigation. Findings of this report are limited to data collected from noted explorations advanced and do not account for unidentified fill zones, unsuitable soil types or conditions, and variability in soil moisture and groundwater conditions. To avoid possible misinterpretations of findings, conclusions, and implications of this report, MTI should be retained to explain the report contents to other design professionals as well as construction professionals. Since actual subsurface conditions on the site can only be verified by earthwork, note that construction recommendations are based on general assumptions from selective observations and selective field exploratory sampling. Upon commencement of construction, such conditions may be identified that require corrective actions, and these required corrective actions may impact the project budget. Therefore, construction recommendations in this report should be considered preliminary, and MTI should be retained to observe actual subsurface conditions during earthwork construction activities to provide additional construction recommendations as needed. Since geotechnical reports are subject to misinterpretation, do not separate the soil logs from the report. Rather, provide a copy of, or authorize for their use, the complete report to other design professionals or contractors. Locations of exploratory sites referenced within this report should be considered approximate locations only. For more accurate locations, services of a professional land surveyor are recommended. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 5 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections This report is also limited to information available at the time it was prepared. In the event additional information is provided to MTI following publication of our report, it will be forwarded to the client for evaluation in the form received. Environmental Concerns Comments in this report concerning either onsite conditions or observations, including soil appearances and odors, are provided as general information. These comments are not intended to describe, quantify, or evaluate environmental concerns or situations. Since personnel, skills, procedures, standards, and equipment differ, a geotechnical investigation report is not intended to substitute for a geoenvironmental investigation or a Phase IVIII Environmental Site Assessment. If environmental services are needed, MTI can provide, via a separate contract, those personnel who are trained to investigate and delineate soil and water contamination. SITE DESCRIPTION Site Access Access to the site may be gained via Interstate 84 to the Ten Mile Road exit. Proceed north on Ten Mile Road approximately 4.7 miles to its intersection with Highway 20/26. From this intersection, proceed west 1.7 miles to its intersection with Pollard Lane. The site occupies the northeast corner of this intersection. Presently the site exists as an agricultural field. The location is depicted on site map plates included in the Appendix. Regional Geology The project site is located within the western Snake River Plain of southwestern Idaho and eastern Oregon. The plain is a northwest trending rift basin, about 45 miles wide and 200 miles long, that developed about 14 million years ago (Ma) and has since been occupied sporadically by large inland lakes. Geologic materials found within and along the plain's margins reflect volcanic and fluvial/lacustrine sedimentary processes that have led to an accumulation of approximately 1 to 2 km of interbedded volcanic and sedimentary deposits within the plain. Along the margins of the plain, streams that drained the highlands to the north and south provided coarse to fine-grained sediments eroded from granitic and volcanic rocks, respectively. About 2 million years ago the last of the lakes was drained and since that time fluvial erosion and deposition has dominated the evolution of the landscape. The project site is underlain by the "Gravel of Whitney Terrace" as mapped by Othberg and Stanford (1993). Sediments of the Whitney terrace consist of sandy pebble and cobble gravel. The Whitney terrace is the second terrace above modern Boise River floodplain, is thickest toward its eastern extent, and is mantled with 2-6 feet of loess. General Site Characteristics This proposed development consists of an approximately 0.35 mile length of proposed roadway that is relatively flat and level terrain. Throughout the majority of the site, surficial soils consist of fine-grained silt soils. Vegetation primarily consists of onions at the time of the investigation. An irrigation ditch runs through the southern boundary of the project site. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 6 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections Regional drainage is north and west toward the Boise River. Stormwater drainage for the site is achieved by percolation through surficial soils. The site is situated so that it is unlikely that it will receive any stormwater drainage from off -site sources. Stormwater drainage collection and retention systems are not in place on the project site and were not noted within the vicinity of the project site. Regional Site Climatology and Geochemistry According to the Western Regional Climate Center, the average precipitation for the Treasure Valley is on the order of 10 to 12 inches per year, with an annual snowfall of approximately 20 inches and a range from 3 to 49 inches. The monthly mean daily temperatures range from 21°F to 95°F, with daily extremes ranging from -25°F to I I I'F. Winds are generally from the northwest or southeast with an annual average wind speed of approximately 9 miles per hour (mph) and a maximum of 62 mph. Soils and sediments in the area are primarily derived from siliceous materials and exhibit low electro-chemical potential for corrosion of metals or concretes. Local aggregates are generally appropriate for Portland cement and lime cement mixtures. Surface water, groundwater, and soils in the region typically have pH levels ranging from 7.2 to 8.2. SOILS EXPLORATION Exploration and Sampling Procedures Field exploration conducted to determine engineering characteristics of subsurface materials included a reconnaissance of the project site and investigation by test pit. Test pits were located in the field by a representative of Brighton Corporation prior to MTI's arrival on the site and Global Positioning System (GPS) device was used to obtain longitude and latitude of test pit sites and are reportedly accurate to within ten feet. Upon completion of investigation, each test pit was backfilled with loose excavated materials. Re -excavation and compaction of these test pit areas are required prior to construction of overlying structures. In addition, samples were obtained from representative soil strata encountered. Samples obtained have been visually classified in the field by professional staff, identified according to test pit number and depth, placed in sealed containers, and transported to our laboratory for additional testing. Subsurface materials have been described in detail on logs provided in the Appendix. Results of field and laboratory tests are also presented in the Appendix. MTI recommends that these logs not be used to estimate fill material quantities. Laboratory Testing Program Along with our field investigation, a supplemental laboratory testing program was conducted to determine additional pertinent engineering characteristics of subsurface materials necessary in an analysis of anticipated behavior of the proposed structures. Laboratory tests were conducted in accordance with current applicable American Society for Testing and Materials (ASTM) specifications, and results of these tests are to be found on the accompanying logs located in the Appendix. The laboratory testing program for this report included: Atterberg Limits Testing — ASTM D4318, Grain Size Analysis — ASTM CI17/C136, and Resistance Value (R-value) and Expansion Pressure of Compacted Soils — Idaho T-8. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 7 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections Soil and Sediment Profile The profile below represents a generalized interpretation for the project site. Note that on site soils strata, encountered between test pit locations, may vary from the individual soil profiles presented in the logs, which can be found in the Appendix. The materials encountered during exploration were quite typical for the geologic area mapped as Gravel of Whitney Terrace. Surficial soils were predominately silt with sand and sandy silt soils. Silts with sand and sandy silts were dark brown to brown, dry to slightly moist, stiff to hard, and contained fine-grained sand. In test pit 5, silty sand with gravel fills were encountered at ground surface. Silty sand with gravel fills were light brown to brown, dry, medium dense to dense, and contained fine to coarse -grained sand. Plow zones/disturbed zones should be expected throughout the length of the roadway. Actual depths of these zones are unknown at this time since test pits were kept to the edges of the crops. Underlying the silts with sand and sandy silts were silty sand sediments. Silty sands were brown to light brown, dry to slightly moist, dense to very dense, and contained fine to medium -grained sand and varying degrees of calcium carbonate cementation and induration. At depth in all the test pits were poorly graded gravel with sand sediments. Poorly graded gravels were light brown, dry to saturated, medium dense to dense, and contained fine to coarse -grained sand, fine to coarse gravel, and 6-inch-minus cobbles. Competency of test pit walls varied little across the site. In general, fine grained soils remained stable while more granular sediments readily sloughed. However, moisture contents will also affect wall competency with saturated soils having a tendency to readily slough when under load and unsupported. Volatile Organic Scan No environmental concerns were identified prior to commencement of the investigation. Therefore, soils obtained during on -site activities were not assessed for volatile organic compounds by portable photoionization detector. Samples obtained during our exploration activities exhibited no odors or discoloration typically associated with this type of contamination. Groundwater encountered did not exhibit obvious signs of contamination. SITE HYDROLOGY Existing surface drainage conditions are defined in the General Site Characteristics section. Information provided in this section is limited to observations made at the time of the investigation. Either regional or local ordinances may require information beyond the scope of this report. Groundwater During this field investigation, groundwater was encountered in test pit 5 at a depth of 15.2 feet bgs. Soil moistures in the test pits were generally dry to slightly moist within surficial soils. Within the poorly graded gravels, soil moistures graded from dry to saturated as the water table was approached and penetrated. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 8 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections In the vicinity of the project site, groundwater levels are controlled in large part by residential and aggricultural irrigation activity and leakage from nearby irrigation ditches and canals. Maximum groundwater elevations likely occur during the later portion of the irrigation season. During previous investigations performed in September 2011 and May 2013 within approximately 1/2-mile to the east and northeast of the project site, no evidence of groundwater was noted within test pits advanced to depths as great as 13.5 to 15.0 feet bgs. Furthermore, according to United States Geological Survey (USGS) monitoring well data within approximately 1/2-mile of the project site, groundwater was measured at depths ranging between 20 and 30 feet bgs. Based on evidence of this investigation and background knowledge of the area, MTI estimates groundwater depths to remain greater than approximately 13 feet bgs throughout the year. This depth can be confirmed through long-term groundwater monitoring. Soil Infiltration Rates Soil permeability, which is a measure of the ability of a soil to transmit a fluid, was not tested in the field. Given the absence of direct measurements, for this report an estimation of infiltration is presented using generally recognized values for each soil type and gradation. Of soils comprising the generalized soil profile for this study, silt with sand soils generally offer little permeability, with typical hydraulic infiltration rates of less than 2 inches per hour. Sandy silt soils will commonly exhibit infiltration rates from 2 to 4 inches per hour and silty sand sediments usually display rates of 4 to 8 inches per hour; though calcium carbonate cementation and induration may reduce these values to near zero. Poorly graded gravel sediments typically exhibit infiltration values in excess of 12 inches per hour. Infiltration testing is generally not required within these sediments because of their free -draining nature. PAVEMENT DISCUSSION AND RECOMMENDATIONS Recommended Pavement Sections As required by Ada County Highway District (ACHD), MTI has used a traffic index of 6 to determine the necessary pavement cross-section for the site. MTI has made assumptions for traffic loading variables based on the character of the proposed construction. The Client should review these assumptions to make sure they reflect intended use and loading of pavements both now and in the future. MTI collected a sample of near - surface soils for Resistance Value (R-value) testing representative of soils to depths of 2 feet below existing ground surface. This sample, consisting of sandy silt collected from test pit 4, yielded a R-value of 12. The following are minimum thickness requirements for assured pavement function. Depending on site conditions, additional work, e.g. soil preparation, may be required to support construction equipment. These have been listed within the Soft Subgrade Soils section. Results of the test are graphically depicted in the Appendix. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS TESTI NG & INSPECTION ❑ Environmental Services ❑ Geotechnical Engineering Flexible Pavement Section ❑ Construction Materials Testing 31 August 2016 Page # 9 of 26 b 161073 g_geotech.docx ❑ Special Inspections The Gravel Equivalent Method, as defined in Section 500 of the State of Idaho Department of Transportation (ITD) Materials Manual, was used to develop the pavement sections. ACHD parameters for traffic index and substitution ratios, which were obtained from the ACHD Policy Manual, were also used in the design. Calculation sheet provided in the Appendix indicate the soils constant, traffic loading, traffic projections, and material constants used to calculate the pavement sections. MTI recommends that materials used in the construction of asphaltic concrete pavements meet the requirements of the ISPWC Standard Specification for Highway Construction. Construction of the pavement section should be in accordance with these specifications and should adhere to guidelines recommended in the section on Construction Considerations. Gravel Equivalent Method Flexible Pavement Specifications Pavement Section Component ffiIIIIIIIIIIIIIII Roadway Section Asphaltic Concrete 2.5 Inches Crushed Aggregate Base 4.0 Inches Structural Subbase 12.0 Inches Compacted Subgradez Not Required for Native Soils 12.0 Inches to 95% of ASTM D698 for Existing Fill Materials/Plow Zones 1It will be required for MTI personnel to verify subgrade competency at the time of construction. 2Depending on the time of year construction takes place, the subgrade soils may be unstable because of high moisture contents. If unstable conditions are encountered, over -excavation and replacement with granular structural fill and/or use of geotextiles may be required. Asphaltic Concrete: Asphalt mix design shall meet the requirements of ISPWC, Section 810 Class III plant mix. Materials shall be placed in accordance with ISPWC Standard Specifications for Highway Construction. Aggregate Base: Material complying with ISPWC Standards for Crushed Aggregate Materials. Structural Subbase: Material complying with requirements for granular structural fill (uncrushed) as defined in ISPWC. Common Pavement Section Construction Issues The subgrade upon which above pavement sections are to be constructed must be properly stripped, inspected, and proof -rolled. Proof rolling of subgrade soils should be accomplished using a heavy rubber -tired, fully loaded, tandem -axle dump truck or equivalent. Verification of subgrade competence by MTI personnel at the time of construction is required. Fill materials on the site must demonstrate the indicated compaction prior to placing material in support of the pavement section. MTI anticipated that pavement areas will be subjected to moderate traffic. MTI does not anticipate pumping material to become evident during compaction, but subgrade clays and silts near and above optimum moisture contents may tend to pump. Pumping or soft areas must be removed and replaced with structural fill. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 10 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections Fill material and aggregates in support of the pavement section must be compacted to no less than 95 percent of the maximum dry density as determined by ASTM D698 for flexible pavements and by ASTM D 1557 for rigid pavements. If a material placed as a pavement section component cannot be tested by usual compaction testing methods, then compaction of that material must be approved by observed proof rolling. Minor deflections from proof rolling for flexible pavements are allowable. Deflections from proof rolling of rigid pavement support courses should not be visually detectable. MTI recommends that rigid concrete pavement be provided for heavy garbage receptacles. This will eliminate damage caused by the considerable loading transferred through the small steel wheels onto asphaltic concrete. Rigid concrete pavement should consist of Portland Cement Concrete Pavement (PCCP) generally adhering to ITD specifications for Urban Concrete. PCCP should be 6 inches thick on a 4-inch drainage fill course and should be reinforced with welded wire fabric. The 4-inch drainage mat should consist of a sand and gravel mixture, complying with Idaho Standards for Public Works Construction (ISPWC) specifications for 3/4-inch (Type 1) crushed aggregate. A moisture -retarder should be placed beneath floor slabs to minimize potential ground moisture effects on moisture -sensitive floor coverings. The granular mat should be compacted to no less than 95 percent of the maximum dry density as determined by ASTM D1557. Upon request, MTI can provide further consultation regarding installation. Control joints must be on 12-foot centers or less. CONSTRUCTION CONSIDERATIONS Recommendations in this report are based upon pavement sections of the project being founded on competent silt soils with sand soils, sandy silt soils, or compacted structural fill. Structural areas should be stripped to an elevation that exposes these soil types. Earthwork Excessively organic soils, deleterious materials, or disturbed soils generally undergo high volume changes when subjected to loads, which is detrimental to subgrade behavior in the area of pavements, floor slabs, structural fills, and foundations. Agricultural crops with associated root systems were noted at the time of our investigation. It is recommended that organic or disturbed soils, if encountered, be removed to depths of 1 foot (minimum), and wasted or stockpiled for later use. Stripping depths should be adjusted in the field to assure that the entire root zone or disturbed zone (plow depths) or topsoil are removed prior to placement and compaction of structural fill materials. Exact removal depths should be determined during grading operations by MTI personnel, and should be based upon subgrade soil type, composition, and firmness or soil stability. If underground storage tanks, underground utilities, wells, or septic systems are discovered during construction activities, they must be decommissioned then removed or abandoned in accordance with governing Federal, State, and local agencies. Excavations developed as the result of such removal must be backfilled with structural fill materials as defined in the Structural Fill section. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 11 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections MTI should oversee subgrade conditions (i.e., moisture content) as well as placement and compaction of new fill (if required) after native soils are excavated to design grade. Recommendations for structural fill presented in this report can be used to minimize volume changes and differential settlements that are detrimental to the behavior of footings, pavements, and floor slabs. Sufficient density tests should be performed to properly monitor compaction. For structural fill beneath parking and driveway areas, one in - place density test per lift for every 10,000 square feet is recommended. Dry Weather If construction is to be conducted during dry seasonal conditions, many problems associated with soft soils may be avoided. However, some rutting of subgrade soils may be induced by shallow groundwater conditions related to springtime runoff or irrigation activities during late summer through early fall. Solutions to problems associated with soft subgrade soils are outlined in the Soft Subgrade Soils section. Problems may also arise because of lack of moisture in native and fill soils at time of placement. This will require the addition of water to achieve near -optimum moisture levels. Low -cohesion soils exposed in excavations may become friable, increasing chances of sloughing or caving. Measures to control excessive dust should be considered as part of the overall health and safety management plan. Wet Weather If construction is to be conducted during wet seasonal conditions (commonly from mid -November through May), problems associated with soft soils must be considered as part of the construction plan. During this time of year, fine-grained soils such as silts and clays will become unstable with increased moisture content, and eventually deform or rut. Additionally, constant low temperatures reduce the possibility of drying soils to near optimum conditions. Soft Subgrade Soils Shallow fine-grained subgrade soils that are high in moisture content should be expected to pump and rut under construction traffic. During periods of wet weather, construction may become very difficult if not impossible. The following recommendations and options have been included for dealing with soft subgrade conditions: • Track -mounted vehicles should be used to strip the subgrade of root matter and other deleterious debris. Heavy rubber -tired equipment should be prohibited from operating directly on the native subgrade and areas in which structural fill materials have been placed. Construction traffic should be restricted to designated roadways that do not cross, or cross on a limited basis, proposed roadway or parking areas. • Soft areas can be over -excavated and replaced with granular structural fill. • Construction roadways on soft subgrade soils should consist of a minimum 2-foot thickness of large cobbles of 4 to 6 inches in diameter with sufficient sand and fines to fill voids. Construction entrances should consist of a 6-inch thickness of clean, 2-inch minimum, angular drain -rock and must be a minimum of 10 feet wide and 30 to 50 feet long. During the construction process, top dressing of the entrance may be required for maintenance. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 12 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections • Scarification and aeration of subgrade soils can be employed to reduce the moisture content of wet subgrade soils. After stripping is complete, the exposed subgrade should be ripped or disked to a depth of 11/2 feet and allowed to air dry for 2 to 4 weeks. Further disking should be performed on a weekly basis to aid the aeration process. • Alternative soil stabilization methods include use of geotextiles, lime, and cement stabilization. MTI is available to provide recommendations and guidelines at your request. Frozen Subgrade Soils Prior to placement of structural fill materials or foundation elements, frozen subgrade soils must either be allowed to thaw or be stripped to depths that expose non -frozen soils and wasted or stockpiled for later use. Stockpiled materials must be allowed to thaw and return to near -optimal conditions prior to use as structural fill. The onsite, shallow silt soils are susceptible to frost heave during freezing temperatures. For exterior flatwork and other structural elements, adequate drainage away from subgrades is critical. Compaction and use of structural fill will also help to mitigate the potential for frost heave. Complete removal of frost susceptible soils for the full frost depth, followed by replacement with a non -frost susceptible structural fill, can also be used to mitigate the potential for frost heave. MTI is available to provide further guidance/assistance upon request. Structural Fill Soils recommended for use as structural fill are those classified as GW, GP, SW, and SP in accordance with the Unified Soil Classification System (USCS) (ASTM D2487). Use of silty soils (USCS designation of GM, SM, and ML) as structural fill may be acceptable. These materials require very high moisture contents for compaction and require a long time to dry out if natural moisture contents are too high and may also be susceptible to frost heave under certain conditions. Therefore, these materials can be quite difficult to work with as moisture content, lift thickness, and compactive effort becomes difficult to control. If silty soil is used for structural fill. lift thicknesses should not exceed 6 inches (loose). and fill material moisture must be closelv monitored at both the working elevation and the elevations of materials already placed. Following placement, silty soils must be protected from degradation resulting from construction traffic or subsequent construction. Recommended granular structural fill materials, those classified as GW, GP, SW, and SP, should consist of a 6-inch minus select, clean, granular soil with no more than 50 percent oversize (greater than 3/4-inch) material and no more than 12 percent fines (passing No. 200 sieve). These fill materials should be placed in layers not to exceed 12 inches in loose thickness. Prior to placement of structural fill materials, surfaces must be prepared as outlined in the Construction Considerations section. Structural fill material should be moisture - conditioned to achieve optimum moisture content prior to compaction. All fill materials must be monitored during placement and tested to confirm compaction requirements, outlined below, have been achieved. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 13 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections Each layer of structural fill must be compacted, as outlined below: • Below Structures and Rigid Pavements: A minimum of 95 percent of the maximum dry density as determined by ASTM D 1557. • Below Flexible Pavements: A minimum of 92 percent of the maximum dry density as determined by ASTM D1557 or 95 percent of the maximum dry density as determined by ASTM D698. The ASTM D 1557 test method must be used for samples containing up to 40 percent oversize (greater than 3/4— inch) particles. If material contains more than 40 percent but less than 50 percent oversize particles, compaction of fill must be confirmed by proof rolling each lift with a 10-ton vibratory roller (or equivalent) until the maximum density has been achieved. Density testing must be performed after each proof rolling pass until the in -place density test results indicate a drop (or no increase) in the dry density, defined as maximum density or "break over" point. The number of required passes should be used as the requirements on the remainder of fill placement. Material should contain sufficient fines to fill void spaces, and must not contain more than 50 percent oversize particles. Excavations Shallow excavations that do not exceed 4 feet in depth may be constructed with side slopes approaching vertical. Below this depth, it is recommended that slopes be constructed in accordance with Occupational Safety and Health Administration (OSHA) regulations, Section 1926, Subpart P. Based on these regulations, on -site soils are classified as type "C" soil, and as such, excavations within these soils should be constructed at a maximum slope of 1'/2 feet horizontal to 1 foot vertical (11/2:1) for excavations up to 20 feet in height. Excavations in excess of 20 feet will require additional analysis. Note that these slope angles are considered stable for short-term conditions only, and will not be stable for long-term conditions. During the subsurface exploration, test pit sidewalls generally exhibited little indication of collapse; however, sloughing of fill materials and native granular sediments from test pit sidewalls was observed, particularly after penetration of the water table. For deep excavations, native granular sediments cannot be expected to remain in position. These materials are prone to failure and may collapse, thereby undermining upper soil layers. This is especially true when excavations approach depths near the water table. Care must be taken to ensure that excavations are properly backfilled in accordance with procedures outlined in this report. Groundwater Control Groundwater was encountered during the investigation but is anticipated to be below the depth of most construction. Special precautions may be required for control of surface runoff and subsurface seepage. It is recommended that runoff be directed away from open excavations. Silty and clayey soils may become soft and pump if subjected to excessive traffic during time of surface runoff. Ponded water in construction areas should be drained through methods such as trenching, sloping, crowning grades, nightly smooth drum rolling, or installing a French drain system. Additionally, temporary or permanent driveway sections should be constructed if extended wet weather is forecasted. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 14 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections GENERAL COMMENTS When plans and specifications are complete, or if significant changes are made in the character or location of the proposed roadway, consultation with MTI should be arranged as supplementary recommendations may be required. Suitability of subgrade soils and compaction of structural fill materials must be verified by MTI personnel prior to placement of structural elements. Additionally, monitoring and testing should be performed to verify that suitable materials are used for structural fill and that proper placement and compaction techniques are utilized. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 als www.mti-id.com • mti(a2mti-id.com Copytingght &I s eMate Inc. Testing & Inspection, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 15 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections REFERENCES Ada County Highway District (ACHD) (2013). Ada County Highway District Policy Manual (October 2015). [Online] Available: <http://www.achdidaho.org/AboutACHD/PolicyManual.aspx> (2016). American Society for Testing and Materials (ASTM) (2013). Standard Test Method for Materials Finer than 75-gm (No. 200) Sieve in Mineral Aggregates by Washing: ASTM C117. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2014). Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates: ASTM C136. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2012). Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort: ASTM D698. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2012). Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort: ASTM D1557. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2013). Standard Test Methods for Resistance Value (R-Value) and Expansion Pressure of Compacted Soils: ASTM D2844. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2011). Standard Practice for Classification of Soils for EngineeringPurposes (Unified Soil Classification System): ASTM D2487. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2010). Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils: ASTM D4318. West Conshohocken, PA: ASTM. Desert Research Institute. Western Regional Climate Center. [Online] Available: <http://www.wrcc.dri.edu/> (2016). Local Highway Technical Assistance Council (LHTAC) (2010). Idaho Standards for Public Works Construction, 2010. Boise, ID: Author. Othberg, K. L. and Stanford, L. A., Idaho Geologic Society (1992). Geologic Map of the Boise Valley and Adjoining Area, Western Snake River Plain, Idaho. (scale 1:100,000). Boise, ID: Joslyn and Morris. U.S. Department of Labor, Occupational Safety and Health Administration. CFR 29, Part 1926, Subpart P: Safety and Health Regulations for Construction, Excavations (1986). [Online] Available: <www.osha.gov> (2016). U.S. Geological Survey (2016). National Water Information System: Web Interface. [Online] Available: <http://waterdata.usgs.gov/nwis> (2016). 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 16 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections APPENDICES ACRONYM LIST AASHTO: American Association of State Highway and Transportation Officials ACHD: Ada County Highway District ACI American Concrete Institute ASCE American Society of Civil Engineers ASTM: American Society for Testing and Materials bgs: below ground surface CBR: California Bearing Ratio D: natural dry unit weight, pcf ESAL Equivalent Single Axle Load GS: grab sample IBC: International Building Code IDEQ Idaho Department of Environmental Quality ISPWC: Idaho Standards for Public Works Construction ITD: Idaho Transportation Department LL: Liquid Limit M: water content MSL: mean sea level N: Standard "N" penetration: blows per foot, Standard Penetration Test NP: nonplastic OSHA Occupational Safety and Health Administration PCCP: Portland Cement Concrete Pavement PERM: vapor permeability PI: Plasticity Index PID: photoionization detector PVC: polyvinyl chloride Qc: cone penetrometer value, unconfined compressive strength, psi Qp: Penetrometer value, unconfined compressive strength, tsf Qu: Unconfined compressive strength, tsf RMR Rock Mass Rating RQD Rock Quality Designation R-Value Resistance Value SPT: Standard Penetration Test (140:pound hammer falling 30 in. on a 2:in. split spoon) USCS: Unified Soil Classification System USDA: United States Department of Agriculture UST: underground storage tank V: vane value, ultimate shearing strength, tsf 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS TESTI NG & INSPECTION ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing GEOTECHNICAL GENERAL NOTES 31 August 2016 Page # 17 of 26 b 161073 g_geotech.docx ❑ Special Inspections RELATIVE DENSITY AND CONSISTENCY CLASSIFICATION Coarse -Grained Soils SPT Blow Counts (N) Fine -Grained Soils SPT Blow Counts (N) Very Loose: < 4 Very Soft: < 2 Loose: 4-10 Soft: 2-4 Medium Dense: 10-30 Medium Stiff: 4-8 Dense: 30-50 Stiff. 8-15 Very Dense: >50 Very Stiff. 15-30 Hard: >30 Moisture Content Description Field Test Dry Absence of moisture, dusty, dry to touch Moist Damp but not visible moisture Wet Visible free water, usually soil is below water table Cementation Descri tion Field Test Weakly Crumbles or breaks with handling or slight finger pressure Moderately Crumbles or beaks with considerable finger pressure Strongly Will not crumble or break with finger pressure PARTICLE SIZE Boulders: >12 in. Coarse -Grained Sand: 5 to 0.6 mm Silts: 0.075 to 0.005 mm Cobbles: 12 to 3 in. Medium -Grained Sand: 0.6 to 0.2 mm Clays: <0.005 mm Gravel: 3 in. to 5 mm Fine -Grained Sand: 0.2 to 0.075 mm UNIFIED SOIL CLASSIFICATION SYSTEM Major Divisions Symbol Soil Descriptions Coarse -Grained Soils <50% passes No.200 sieve Gravel & Gravelly Soils <50% coarse fraction passes No.4 sieve GW Well -graded gravels; gravel/sand mixtures with little or no fines GP Poorly -graded gravels; gravel/sand mixtures with little or no fines GM Silty gravels; poorly -graded gravel/sand/silt mixtures GC Clayey gravels; poorly -graded gravel/sand/clay mixtures Sand & Sandy Soils >50% coarse fraction passes No.4 sieve SW Well -graded sands; gravelly sands with little or no fines SP Poorly -graded sands; gravelly sands with little or no fines SM Silty sands; poorly -graded sand/gravel/silt mixtures SC Clayey sands; poorly -graded sand/gravel/clay mixtures Fine Grained Soils >50% passes No.200 sieve Silts & Clays LL < 50 ML Inorganic silts; sandy, gravelly or clayey silts CL Lean clays; inorganic, gravelly, sandy, or silty, low to medium -plasticity clays OL Organic, low -plasticity clays and silts Silts & Clays LL > 50 MH Inorganic, elastic silts; sandy, gravelly or clayey elastic silts CH Fat clays; high -plasticity, inorganic clays OH Organic, medium to high -plasticity clays and silts Highly Organic Soils PT Peat, humus, hydric soils with high organic content 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(c)mti-id.com Copytingght &I s1e Materialsnc. Testing & Inspedian, Inc. MATERIALS TESTI NG & INSPECTION ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing GEOTECHNICAL INVESTIGATION TEST PIT LOG 31 August 2016 Page # 18 of 26 b161073g_geotech.docx ❑ Special Inspections Test Pit Log #: TP-1 Date Advanced: 19 Aug 2016 Logged by: Jacob Schlador, E.I.T. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Latitude: 43.6639557 Longitude:-116.4682846 Depth to Water Table: Not Encountered Total Depth: 11.2 Feet bgs Depth Field Description and USCS Soil and Sediment Sample Sample Depth Qp Lab Feet bgs) Classification Type Feet bgs) Test ID Silt with Sand (ML): Dark brown, slightly moist, 0.0-1.9 stiff to very stiff, with fine-grained sand. 1.5-2.5 --Organics to a depth of 0.8 foot bgs. Silty Sand (SM): Brown, dry to slightly moist, dense to very dense, with fine to medium -grained 1.9-3.7 sand. --A thin layer of weak calcium carbonate cementation encountered at 2.7 eet bgs. Poorly Graded Gravel with Sand (GP): Light 3.7-11.2 brown, dry to slightly moist, medium dense to dense, with fine to coarse -grained sand, fine to coarse gravel, and 4-inch-minus cobbles. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(a2mti-id.com Copyting&2s9e Materialsnc. Testing &Inspection, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 19 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP-2 Date Advanced: 19 Aug 2016 Excavated by: Struckman's Backhoe Service Latitude: 43.6665344 Depth to Water Table: Not Encountered Notes: Piezometer installed to 15.0 feet bgs. Logged by: Jacob Schlador, E.I.T. Location: See Site Map Plates Longitude:-116.4682312 Total Depth: 15.0 Feet bgs Depth Field Description and USCS Soil and Sediment Sample Sample Depth Qp Lab Feet bgs) Classification Type Feet bgs) Test ID Silt with Sand (ML): Dark brown to brown, 0.0-4.3 slightly moist, stiff to hard, with fine-grained 2.0-4.5 sand. --Organics to a depth of 0.9 oot bgs. Silty Sand (SM): Brown, dry to slightly moist, dense to very dense, with fine to medium -grained sand. 4.3-11.1 --Moderate to strong induration encountered from 4.3 to 7.1 feet bgs. --Moderate calcium carbonate cementation encounteredfrom 7.1 to 9.],feet bgs. Poorly Graded Gravel with Sand (GP): Light 11.1-15.0 brown, dry to slightly moist, medium dense to dense, with fine to coarse -grained sand, fine to coarse gravel, and 6-inch-minus cobbles. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 als www.mti-id.com • mti(abmti-id.com Copyting&2s9e Mate Inc. Testing &Inspection, Inc. MATERIALS TESTI NG & INSPECTION ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing GEOTECHNICAL INVESTIGATION TEST PIT LOG 31 August 2016 Page # 20 of 26 b161073g_geotech.docx ❑ Special Inspections Test Pit Log #: TP-3 Date Advanced: 19 Aug 2016 Logged by: Jacob Schlador, E.I.T. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Latitude: 43.6664276 Longitude:-116.4586716 Depth to Water Table: Not Encountered Total Depth: 8.1 Feet bgs Depth Field Description and USCS Soil and Sediment Sample Sample Depth Qp Lab Feet b s Classification Type Feet b s Test ID Silt with Sand (ML): Dark brown, dry to slightly 0.0-3.4 moist, very stiff, with fine-grained sand. 2.5-3.75 --No organics noted within the test pit. Silty Sand (SM): Brown to light brown, dry to slightly moist, dense to very dense, with fine to 3.4-6.2 medium -grained sand. --Weak to moderate calcium carbonate cementationfrom 3.6 to 4.1 eet b s. Poorly Graded Gravel with Sand (GP): Light 6.2-8.1 brown, dry, medium dense to dense, with fine to coarse -grained sand, fine to coarse gravel, and )- inch -minus cobbles. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(a2mti-id.com Copyting&2s9e Materialsnc. Testing &Inspection, Inc. MATERIALS TESTI NG & INSPECTION ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing GEOTECHNICAL INVESTIGATION TEST PIT LOG 31 August 2016 Page # 21 of 26 b 161073 g_geotech.docx ❑ Special Inspections Test Pit Log #: TP-4 Date Advanced: 19 Aug 2016 Logged by: Jacob Schlador, E.I.T. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Latitude: 43.6635551 Longitude:-116.4601364 Depth to Water Table: Not Encountered Total Depth: 7.9 Feet bgs Depth Field Description and USCS Soil and Sediment Sample Sample Depth Qp Lab Feet b s Classification Type Feet b s Test ID Sandy Silt (ML): Dark brown to brown, dry to 0.0-3.7 slightly moist, stiff to very stiff, with fine-grained Bulk 0.5-1.0 1.25-3.0 A/ sand. R-Value --Organics to a depth of 0.8 oot b s. Silty Sand (SM): Brown, dry, dense to very dense, with fine to medium -grained sand. 3.7-6.1 --Moderate calcium carbonate cementation encounteredfrom 5.1 to 5.4 eet b s. Poorly Graded Gravel with Sand (GP): Light 6.1-7.9 brown, dry, medium dense to dense, with fine to coarse -grained sand, fine to coarse gravel, and 4- inch-minus cobbles. Lab Test ID M LL PI Sieve Analysis (% passing) - % - - #4 #10 #40 #100 9200 A 18.1 28 5 98 96 87 69 61.0 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 als www.mti-id.com • mti(abmti-id.com Copyting&2s9e Mate Inc. Testing &Inspection, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 22 of 26 INSPECTION b 161073g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP-5 Date Advanced: 19 Aug 2016 Excavated by: Struckman's Backhoe Service Latitude: 43.6633445 Depth to Water Table: 15.2 Feet bgs Notes: Piezometer installed to 15.8 feet bgs. Logged by: Jacob Schlador, E.I.T. Location: See Site Map Plates Longitude:-116.4601364 Total Depth: 15.8 Feet bgs Depth (Feet bgs) Field Description and USCS Soil and Sediment Classification Sample Type Sample Depth (Feet bgs) Qp Lab Test ID Silty Sand with Gravel Fill (SM-FILL): Light 0.0-2.3 brown to brown, dry, medium dense to dense, with fine to coarse -grained sand and fine to coarse ravel. Poorly Graded Gravel with Sand (GP): Light 2.3-15.8 brown, dry to saturated, medium dense to dense, with fine to coarse -grained sand, fine to coarse ravel, and 4-inch-minus cobbles. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti(a2mti-id.com Copyting&2s9e Materialsnc. Testing &Inspection, Inc. MATERIALS 31 August 2016 TESTI NG & Page # 23 of 26 INSPECTION b 161073 g_geotech.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections GRAVEL EQUIVALENT METHOD — PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: Pollard Lane Realignment, Rural Road Average Daily Traffic Count: 300 All Lanes & Both Directions Design Life: 20 Years Traffic Index: 6.00 Climate Factor: 1 R-Value of Subgrade: 12.00 Subgrade CBR Value: 5 Subgrade Mr: 7,500 R-Value of Aggregate Base: 80 R-Value of Granular Borrow: 60 Subgrade R-Value: 12 Expansion Pressure of Subgrade: 0.19 Unit Weight of Base Materials: 130 Total Design Life 18 kip ESAL's: 33,131 ASPHALTIC CONCRETE: Gravel Equivalent, Calculated: 0.384 Thickness: 0.196923077 Gravel Equivalent, ACTUAL: 0.41 CRUSHED AGGREGATE BASE: Gravel Equivalent (Ballast): 0.768 Thickness: 0.329 Gravel Equivalent, ACTUAL: 0.773 SUBBASE: Use = 2.5 Inches Use = 4 Inches Gravel Equivalent (Ballast): 1.690 Thickness: 0.917 Use = 12 Inches Gravel Equivalent, ACTUAL: 1.773 TOTAL Thickness: 1.542 Thickness Required by Exp. Pressure: 0.210 Design Depth Inches Asphaltic Concrete (at least 2.5): 2.50 Asphalt Treated Base (at least 4.2): 0.00 Cement Treated Base (at least 4.2): 0.00 Crushed Aggregate Base (at least 4.2): 4.00 Subbase (at least 4.2): 12.00 ACHD Substitution Ratios 1.95 1.10 1.00 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 als www.mti-id.com • mti(d)mti-id.com Copyting&2s9e Mate Inc. Testing &Inspection, Inc. MATERIALS TESTI NG & INSPECTION ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing R-VALUE LABORATORY TEST DATA 31 August 2016 Page # 24 of 26 b161073g geotech.docx ❑ Special Inspections Source and Description: TP-4, 0.5-1.0 — Sandy Silt Date Obtained: August 19, 2016 Sample ID: 16-7545 Sampling and ASTM AASHTO ASTM D75: AASHTO T2: X X Preparation: D421: T87: Test Standard: ASTM AASHTO Idaho T8: X D2844: T 190: Sample A B C Dry Density (lb/ft3) 106.3 104.1 101.7 Moisture Content (%) 17.7 19.5 20.1 Expansion Pressure (psi) 0.51 0.24 0.12 Exudation Pressure (psi) 416 247 134 R-Value 16 13 10 R-Value @ 200 psi Exudation Pressure = 12 R-Value @ Exudation Pressure 17.0 16.0 15.0 14.0 j 13.0 12.0 11.0 10.0 9.0 450 400 350 300 250 200 150 100 Exudation Pressure (psi) 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 www.mti-id.com • mti mti-id.com Copyting&2s9e Materialsnc. Testing &Inspection, Inc. �c CAN ADA RD IJ CAN ADA RD N CAN ADA RD R`° CI A / 4, �. RC CD n � 0 � c- b z G of � IW-N3L,N TE C;) CD 0 rn 0G0 IM<6 F c � Z/�70 S t� � v � N riWl , VILn O Cal a;313+d3 N a. '-- - W N o'o m m0 M Z 0 3 0-0 oG QC7a�a o m 0 w o o �° c n °' 0 a. o o m Z o I Z o v 0 c cn o wm a> °' m m m m w� v ' o rn 0 ID Q� N D W - Y^' o o w - ZA O MT 0 �m/� Y 1 3 M x0 m m � CD 3�N n Z �M 9' Z Ln o CD 3 i POLLARD LANE ► I, II ► O r ► I, 0 O I O r z m I II II LEVILANE _ _ CD ic U1 T! c� D . N O m FIN �mw W N �-� 0N0 z-a r� �D �D m> r z CD m o 0 0 0 -o m z o�c QC7w v era ra n� o O O 0 0 0 0 O m m w cp (D .0 x .O�-. x N x z O N 0 7 N O Or 0 N w 7 O ED N (D 0 (D (D (D CD � m O� N N O O Nm> ® CD CD=o xxo �N� v� CD a(D m 3�N nZM c.0 T N V o� Z in o ® mCD 3 N � N MATERIALS TESTING 6 INSPECTION AN ATLAS COMPANY 4 March 2019 Page # 1 of 6 b 161073 g_addendum# 1-revi sed.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections Mr. Kameron Nauahi Brighton Corporation 12601 West Explore Drive, Suite 200 Boise, ID 83713 208-378-4000 Re: Addendum #1 — Pavement Recommendations Pollard Lane Realignment Pollard Lane & Chinden Boulevard Meridian, ID Dear Mr. Wardle: This addendum report presents recommendations not requested at the time of the previously issued MTI Geotechnical Engineering Report (13161073g). Descriptions of general site characteristics and the proposed project are available in the previous report. Unless otherwise noted in this addendum, all initial recommendations, limitations, and warranties expressed in the previous report must be adhered to. Recommended Pavement Sections As required by Ada County Highway District (ACHD), MTI has used a traffic index of 6 for local streets and 8 for collector and commercial streets to determine the necessary pavement cross-section for the site. MTI has made assumptions for traffic loading variables based on the character of the proposed construction. The Client should review these assumptions to make sure they reflect intended use and loading of pavements both now and in the future. MTI collected a sample of near -surface soils for Resistance Value (R-value) testing representative of soils to depths of 2 feet below existing ground surface. This sample, consisting of sandy silt collected from test pit 4, yielded a R-value of 12. The following are minimum thickness requirements for assured pavement function. Depending on site conditions, additional work, e.g. soil preparation, may be required to support construction equipment. These have been listed within the Soft Subgrade Soils section of the original report. Results of the test are graphically depicted in the Enclosures section. Flexible Pavement Sections The Gravel Equivalent Method, as defined in Section 500 of the State of Idaho Department of Transportation (ITD) Materials Manual, was used to develop the pavement sections. ACHD parameters for traffic index and substitution ratios, which were obtained from the ACHD Policy Manual, were also used in the design. Calculation sheets provided in the Enclosures section indicate the soils constant, traffic loading, traffic projections, and material constants used to calculate the pavement sections. MTI recommends that materials used in the construction of asphaltic concrete pavements meet the requirements of the ISPWC Standard Specification for Highway Construction. Construction of the pavement section should be in accordance with these specifications and should adhere to guidelines recommended in the Construction Considerations section of the original report. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 Copyright www.mti-id.com • mti(c)mti-id.com ght©2019 Testing & Inspection MATERIALS TESTING 6 INSPECTION AN ATLAS COMPANY 4 March 2019 Page #2of6 b 161073 g_addendum# 1-revi sed.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections Gravel Equivalent Method Flexible Pavement Snecifications Pavement Section Local Roadway Section Collectors and Commercial Component' Roadway Sections Asphaltic Concrete 2.5 Inches 3.25 Inches Crushed Aggregate Base 4.0 Inches 4.0 Inches Structural Subbase 12.0 Inches 17.0 Inches Not Required for Native Soils Not Required for Native Soils Compacted Subgrade 12.0 Inches to 95% of ASTM 12.0 Inches to 95% of ASTM D698 for Existing Fill D698 for Existing Fill Materials/Plow Zones Materials/Plow Zones 1It will be required for MTI personnel to verify subgrade competency at the time of construction. Asphaltic Concrete: Asphalt mix design shall meet the requirements of ISPWC, Section 810 Class III plant mix. Materials shall be placed in accordance with ISPWC Standard Specifications for Highway Construction. Aggregate Base: Material complying with ISPWC Standards for Crushed Aggregate Materials. Structural Subbase: Material complying with requirements for granular structural fill (uncrushed) as defined in ISPWC. Common Pavement Section Construction Issues The subgrade upon which above pavement sections are to be constructed must be properly stripped, compacted (if indicated), inspected, and proof -rolled. Proof rolling of subgrade soils should be accomplished using a heavy rubber -tired, fully loaded, tandem -axle dump truck or equivalent. Verification of subgrade competence by MTI personnel at the time of construction is required. Fill materials on the site must demonstrate the indicated compaction prior to placing material in support of the pavement section. MTI anticipated that pavement areas will be subjected to moderate traffic. MTI does not anticipate pumping material to become evident during compaction, but subgrade clays and silts near and above optimum moisture contents may tend to pump. Pumping or soft areas must be removed and replaced with structural fill. Fill material and aggregates in support of the pavement section must be compacted to no less than 95 percent of the maximum dry density as determined by ASTM D698 for flexible pavements and by ASTM D 1557 for rigid pavements. If a material placed as a pavement section component cannot be tested by usual compaction testing methods, then compaction of that material must be approved by observed proof rolling. Minor deflections from proof rolling for flexible pavements are allowable. Deflections from proof rolling of rigid pavement support courses should not be visually detectable. 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 Copyright www.mti-id.com • mti(c)mti-id.com ght©2019 Testing & Inspection MATERIALS TESTING & INSPECTION AN ATLAS COMPANY 4 March 2O19 Page # 3 of 6 1,I61073s addendum##-revised.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections MTI appreciates this opportunity to be of service to you and looks forward to working with you in the future. If you have questions, please call (208) 376-4748. Respectfully Submitted, Materials Testing & Inspection J,O� *4tA,- Jacob Schlador, P.E. Geotechnical Enginee ENS oNc�ti 18300 3 Li l( v'qC qTE OF Reviewed by: Monica Saculles, P.E. Senior Geotechnical Engineer Enclosures: Gravel Equivalent ;Uethod Pavement Thickness Design Procedures R-Value Laboratory Test Data 2791 S Victory View Way - Boise, ID 83709 - (208) 376-4748 - Fax (208) 322-6515 www.mti-id.com - mtinmti-Id.Com Tn M,,q 73 FAalenats sLny 3 mapecunn MATERIALS TESTING 6 INSPECTION 4 March 2019 Page # 4 of 6 b 161073 g_addendum# 1-revi sed.docx AN ATLAS COMPANY ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections GRAVEL EQUIVALENT METHOD — PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: Pollard Subdivision, Local Roadways Average Daily Traffic Count: 300 All Lanes & Both Directions Design Life: 20 Years Traffic Index: 6.00 Climate Factor: 1 R-Value of Subgrade: 12.00 Subgrade CBR Value: 5 Subgrade Mr: 7,500 R-Value of Aggregate Base: 80 R-Value of Granular Borrow: 60 Subgrade R-Value: 12 Fspansion Pressure ofSubgrade: 0.19 Unit Weight of Base Materials: 130 Total Design Life 18 kip ESAL's: 33,131 ASPHALTIC CONCRETE: Gravel Equivalent, Calculated 0.384 Thickness: 0.196923077 Gravel Equivalent, ACTUAL: 0.41 CRUSHED AGGREGATEBASE Gravel Equivalent (Ballast): 0.768 Thickness: 0.329 Gravel Equivalent, ACTUAL: 0.773 SUBBASE Gravel Equivalent (Ballast): 1.690 Thickness: 0.917 Gravel Equivalent, ACTUAL: 1.773 TOTAL Thickness: 1.542 Thickness Required by Exp. Pressure: 0.210 Design Depth Inches Asphaltic Concrete (at least 2.5): 2.50 Asphalt TreatedBase (at least 4.2): 0.00 Cement TreatedBase (at least 4.2): 0.00 Crushed Aggregate Base (at least 4.2): 4.00 Subbase (at least 4.2): 12.00 ACHD Substitution Ratios 1.95 1.10 1.00 Use — 2.5 Inches Use = 4 Inches Use= 12 Inches 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 Copyright www.mti-id.com • mti(c)mti-id.com ght©2019 Testing & Inspection MATERIALS TESTING 6 INSPECTION AN ATLAS COMPANY 4 March 2019 Page # 5 of 6 b 161073 g_addendum# 1-revi sed.docx ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections GRAVEL EQUIVALENT METHOD — PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: Pollard Subdivision, Commercial and Collector Streets Average Daily Traffic Count: 700 All Lanes & Both Directions Design Life: 20 Years Traffic Index: 8.00 Climate Factor: 1 R-Value of Subgrade: 12.00 Subgrade CBR Value: 5 Subgrade Mr: 7,500 R-Value of Aggregate Base: 80 R-Value of Granular Borrow: 60 Subgrade R-Value: 12 Expansion Pressure of Subgrade: 0.19 Unit Weight of Base Materials: 130 Total Design Life 18 kip ESAL's: 371,659 ASPHALTIC CONCRETE: Gravel Equivalent, Calculated: 0.512 Thickness: 0.262564103 Use = 3.25 Inches Gravel Equivalent, ACTUAL: 0.53 CRUSHED AGGREGATE BASE: Gravel Equivalent (Ballast): 1.024 Thickness: 0.451 Use = 4 Inches Gravel Equivalent, ACTUAL: 0.895 SUBBASE: Gravel Equivalent (Ballast): 2.253 Thickness: 1.358 Use = 17 Inches Gravel Equivalent, ACTUAL: 2.311 TOTAL Thickness: 2.021 Thickness Required by Exp. Pressure: 0.210 Design ACHD Depth Substitution Inches Ratios Asphaltic Concrete (at least 2.5): 3.25 1.95 Asphalt Treated Base (at least 4.2): 0.00 Cement Treated Base (at least 4.2): 0.00 Crushed Aggregate Base (at least 4.2): 4.00 1.10 Subbase (at least 4.2): 17.00 1.00 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 copyright www.mti-id.com • mti(c)mti-id.com ght©2019 Testing & Inspection MATERIALS TESTING 6 INSPECTION 4 March 2019 Page # 6 of 6 b 161073 g_addendum#1-revised.docx AN ATLAS COMPANY ❑ Environmental Services ❑ Geotechnical Engineering ❑ Construction Materials Testing ❑ Special Inspections R-VALUE LABORATORY TEST DATA Source and Description: TP-4, 0.5-1.0 — Sandy Silt Date Obtained: August 19, 2016 Sample ID: 16-7545 Sampling and ASTM AASHTO ASTM D75: AASHTO T2: X X Preparation: D421: T87: Test Standard: ASTM AASHTO Idaho T8: X D2844: T190: Sample A B C Dry Density (lb/ft) 106.3 104.1 101.7 Moisture Content (%) 17.7 19.5 20.1 Expansion Pressure (psi) 0.51 0.24 0.12 Exudation Pressure (psi) 416 247 134 R-Value 16 13 10 R-Value @ 200 psi Exudation Pressure = 12 R-Value @ Exudation Pressure 17.0 16.0 15.0 14.0 j 13.0 12.0 11.0 10.0 9.0 450 400 350 300 250 200 150 100 Exudation Pressure (psi) 2791 S Victory View Way • Boise, ID 83709 • (208) 376-4748 • Fax (208) 322-6515 �pYh www.mti-id.com • mti(a2mti-id.com Copyright Materials Testing & Inspection