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CC - Storm Drainage Report
Prepared For: TM Center Subdivision No. 2 Brighton Development, Inc., Meridian, Idaho City of Meridian, and ACHD Storm Drainage Report SS\p N A L eiv6, E N SF'o 6860 s� 8/28/23 0 �0 qTF F /N C. Digitally signed by Lachlin Kinsella, P.E. Date:2023.08.28 15:09:11 -06'00' Prepared By: Lachlin Kinsella, P.E. Project Manager KM Engineering, LLP 5725 North Discovery Way Boise, I D 83713 208.639.6939 Ikinsella@kmengllp.com Ian August 2023 Project No: 23-084 E N G I N E E R I N G TABLE OF CONTENTS Introduction ................................................................................................................................. 1 ProjectDescription ...................................................................................................................... 1 SiteDescription............................................................................................................................... 1 Scopeand Methods........................................................................................................................ 1 Existing Drainage Conditions .......................................................................................................... 1 Proposed Drainage Conditions and Analysis .................................................................................. 1 TemporaryPonds............................................................................................................................ 2 Summary......................................................................................................................................... 3 APPENDICES Appendix A - Figures Figure 1 - Vicinity Map Figure 2 - Post-Development Drainage Map Figure 3 - Storm Water Improvement Plans Appendix B - Tables Table 1 - Peak Flow Rates and Runoff Volumes Appendix C - Calculations Post-Development 25-year Calculations Post-Development 100-year Calculations Temporary Pond Calculations Appendix D - Geotechnical Engineering Report Limited Geotechnical Engineering Report—TM Center Development (MTI, 8/7/19) INTRODUCTION The purpose of this report is to show that the storm drainage facilities for the proposed TM Center Subdivision No. 2 (Project) are designed to meet the City of Meridian, 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 a private drive that connects S. Innovation Ln.to S. Wayfinder Ave, and new utilities. The proposed drive will be privately owned and maintained per the construction plans and connect to the existing ACHD road to the east. SITE DESCRIPTION The Project site is located at the northwest corner of S. Vanguard Way and S. Wayfinder Ave. in Meridian, Idaho. See Appendix A, Figure 1 for a vicinity map of the project. The proposed Project area is approximately 4.22 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) as required by the City of Meridian. 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 forthe temporary ponds were completed to verify capacity. EXISTING DRAINAGE CONDITIONS The pre-project watershed consists of primarily agricultural land that slopes from north to south, with a gravity irrigation pipe system that discharges to the Purdam Gulch Drain. There are no existing storm drainage facilities in place to reduce the peak runoff volumes prior to discharging into the drain. PROPOSED DRAINAGE CONDITIONS AND ANALYSIS The proposed drainage system improvements consist of inlets, pipes, temporary ponds, and modifying an existing ACHD storm drain facility. The post-development site was broken into four (4) new drainage basins as shown in Appendix A, Figure 2 - Post-Development Drainage Map. For land use type and runoff coefficients (.95 — impervious) for each basin, refer to ACHD calculations in Appendix C. Each basin was delineated according to the tributary area draining to each drainage structure or facility such as gutter, inlet, etc. For peak flow rates and the temporary pond required volumes, see Table 1 (Peak Flow Rates and Runoff Volumes). 1 The time of concentration was calculated using shallow concentrated flow for the road curb and gutters. The stormwater runoff from the roads is conveyed using the curb and gutter to inlet locations at the low points and is then retained on site through temporary ponds. The ACHD drainage basins should remain unchanged along S. Wayfinder Ave. The proposed modifications include replacing the Type I inlet with a Type III inlet and relocating the existing storm drain manhole due to conflicts with the proposed driveway approach. TEMPORARY PONDS There are four (4) private temporary ponds that should be built per the civil construction plans. Each temporary pond has been sized to store the 100-year volume and infiltrate 90% of the required volume within a 48-hour period. SUMMARY This report determines that the Project storm water design sizing and analysis conforms to the City of Meridian, ACHD, and the water quality requirements of the Idaho Department of Environmental Quality (DEQ). The post-development storm water runoff for the proposed private drive should be completely retained onsite through the proposed temporary ponds. 2 APPENDIX A - FIGURES 16W 23A A0=FRANKLINN RD._ z PROJECT SITE vi v CTATE 84 ZEN LQ w Ri d ti ti U O a a O o N W N W W N Z Y Z 2 5 0 2000 4000 6000 3 Plan Scale: 1" = 2000' a ENGINEERING 5725 NORTH DISCOVERY WAY BOISE,IDAHO 83713 PHONE(208)639-6939 TM CENTER SUBDIVISION NO. 2 kmengllp.com MERIDIAN, IDAHO X DATE: 8/28/23 a PROJECT: 23-084 a SHEET: FIGURE 1 - VICINITY MAP 0 1 OF 1 a DRAINAGE LEGEND DESIGN POINTS 0 A BASIN DESIGNATION 1. TEMPORARY POND #1 1 2. TEMPORARY POND #2 2.5 AREA IN ACRES 3. TEMPORARY POND #3 4. TEMPORARY POND #4 DESIGN POINT 5. INLET #1 6. SDMH #1 7. EXISTING SEEPAGE EXISTING GRADE CONTOUR BED � 2470— — FINISHED GRADE CONTOUR � 247p �— Lu 1 a J Lu z vi zs I I Ln o L4 I I I q I W �ol � �SBo t I � � — r TOP TM CENTER SUBDIVISION NO. 1 I I III 2 r � i w BLOCK 1 I a z l I I I I I o I l o I I I I I ' I I zl it lI Ln I I I z a - - - - _ _ �I j _ _ \ .1I1 O j _ J � S � � _ ` Co W I EXISTING DRAINAGE — — — — — — — — — BLOCK 1 BASIN, TYP. I •\ W I I < I I T7 rM0 ,13 - - - - - - - - - - - - - - - - - Q Z LLJ — C 1 — �r �/ W W � -PRIVATE DRIVE— 0.09 I I 2574 D-1 \ ® \ Lu W _0 .0a - - - - - - - - - - - - - o.os - - - U p I I EXISTING DRAINAGE I ( I — — — — — �5�� / Lu II I BASIN, TYP. 2 / 2574 —/ 4 / I / �•�^�� f 7 T o 0 Ln �D LLL s[ Q �N � ' 00 C O IT o � U C E N G I N E E R I N G L.L 5725 NORTH DISCOVERY WAY BOISE,IDAHO 83713 O PHONE(208)639-6939 7 kmengllp.com DESIGN BY LCK � DRAWN BY: LCK a CHECKED BY: LCK Q o DATE: AUGUST 2023 z POST DEVELOPMENT DRAINAGE PROJECT: 23084 c— SHEET NO. c 0 60 120 180 J V 1 1 1 Plan Scale: 1" = 60' 1 OF 1 • . .9 / O Ilir N 2 SHEET NOTES A. SEE SHEET C1.1 FOR GENERAL, ACHD, AND UTILITY ASS\ON fNc� 0 30 60 90 NOTES. Q�o�c �\�ENSF10 'Y 10 B. GROUNDWATER ELEVATIONS ARE EXPECTED TO REMAIN Plan Scale: 1 = 30 AT OR BELOW 10.5 FEET FROM EXISTING GROUND SURFACE PER "2022 GROUND WATER MONITORING FINAL 8t28123 0 REPORT - WAYFINDER PROJECT" PREPARED BY NRS, DATED OCTOBER 27, 2022. THE DESIGN INFILTRATION 9� qTF OF \�P� RATE IS APPROXIMATELY 2 IN/HR BASED ON THE RECOMMENDED INFILTRATION RATES. FOR ADDITIONAL y��/�/ C INFORMATION REFER TO THE LIMITED GEOTECHNICAL ENGINEERING REPORT "TM CENTER DEVELOPMENT" PREPARED BY MTI, DATED AUGUST 7, 2019. C. PROVIDE WATER-TIGHT SEALS AT PIPING ENTRANCES/EXITS FOR CATCH BASINS, DIVERSION BOXES, AND MANHOLES. D. ALL STORM PIPE WITHIN ROW SHALL BE C900 WHERE COVER OVER PIPE IS LESS THAN 2 FEET. OUTSIDE OF ROW OR WHERE COVER IS GREATER THAN 2 FEET THE STORM PIPE SHALL BE ADS N-12 HP PIPE OR w APPROVED EQUAL. FLOWABLE FILL SHALL BE USED WHEN a LESS THAN 5-FEET OF SEPARATION BETWEEN STRUCTURES. pi- -P E. ALL DRAINAGE STRUCTURES SHALL BE PER ISPWC STANDARDS AND THE ACHD SUPPLEMENTS TO THE ISPWC. i "SDI- STORM DRAIN STRUCTURES SHALL HAVE HS-25 TRAFFIC RATED LIDS UNLESS OTHERWISE SPECIFIED. 00 I. ° F_ - - F. THE CONTRACTOR SHALL COMPLY WITH ALL THE REQUIREMENTS FOR STORM WATER DISCHARGE ASSOCIATED WITH CONSTRUCTION ACTIVITY. THIS INCLUDES IOW I v IMPLEMENTING THE BMP'S RECOMMENDED IN THE SWPP N a 1 PLAN PREPARED FOR THIS SITE, REGULAR SITE ZO INSPECTIONS, DOCUMENTATION OF MODIFICATIONS TO THE sIs s I s's s"s I I SWPPP AND OTHER REQUIREMENTS AS SET FORTH IN cn 2 THE NPDES GENERAL PERMIT. > w L - - -Ia- - J BLOCKI L ~ H. ALL CHANGES REQUIRE APPROVAL BY THE DESIGN 00 10 ENGINEER AND CITY OF MERIDIAN. FOR CHANGES WITH THE ACHD RIGHT-OF-WAY, APPROVAL FROM ACHD IS REQUIRED. I ° _ w � a j I I. FOR UTILITY CROSSINGS AT SEEPAGE BED LOCATIONS, 3 w THE CONTRACTOR SHALL CONFORM TO THE STANDARDS N I SET BY THE CITY OF MERIDIAN AND SECTION 8200 OF IR i I J AR ACHD STORMWATER GUIDELINES. a m cn zD w J. THE STORM WATER DESIGN IS BASED ON SECTIONS 8000 z 3 0 AND 8200 OF THE 2017 ACHD POLICY MANUAL. O °0 I° cn ¢ O6 INV:2570.65 ° TM CENTER I � I` 1 INV:2571.0006 � v SUBDIVISION No. 1 ` a z I Q w w I 28.7' 12" ADS N-12 HP KEYNOTES O 28.2' 12" ADS N-12 HP N ® 0.97% 00 z ® 0.50% V) w 1. INSTALL TEMPORARY POND #1 (PRIVATE) PER DETAIL, z CITY OF MERIDIAN m �- - - INLET #3 THIS SHEET. 10'Lx10'Wx2'D EASEMENT PER INST. INLET #1 cf w PROPOSED CITY OF ACHD SD-601, TYPE I ACHD SD-601, TYPE I z o MERIDIAN UTILITY EASEMENT I RIM:2573.57 TOP ELEV:2571.00 ;._.' No. 2022-072452 - •• i RIM:2573.59 Q SUMP:2569.93 3 TOE ELEV:2571.00 •I° SUMP:2570.14 0 I INV OUT:2570.93 12" (NE) DESIGN INFILTRATION RATE = 2 IN/HR - a0 3 s INV OUT:2571.14 12" (N) F - - VOLUME REQUIRED = 262 CIFCO F VOLUME PROVIDED = 346 CIF - - - - - - - _ PROPOSED CITY OF - - -- - - - - - - - - T- - - - - - - - - -- - - - _ •� MERIDIAN UTILITY EASEMENT 2. INSTALL TEMPORARY POND #2 (PRIVATE) PER DETAIL, _ THIS SHEET. 10'Lx10'Wx2'D Ln \ TOP ELEV:2573.00 r - - 1 8 W - 8 W - - 8 W - - 8 W - - 8 W - - a W- - -$ - - -8 8 W - - - 8 W - - - 8 W- - -8 W - - 8 W 8 W 8 W 8 W 8 W 8 a - - - - - - - - - - - - - I I , PRIVATE DRIVE _ _ TOE ELEV:INFILTRATION 0 s's s - " g •• �� .. „ DESIGN INFILTRATION RATE = 2 IN/HR I a0 s s••�� }ma's-ems s�s s - - - - - - _ - s-'- VOLUME VOLUME REQUIRED = 262 CIFI �c 7.7' 18" ADS N-12 HP - -84 - - - - - - - - - - \ �s"s /© 0.00% I VOLUME PROVIDED = 346 CIF - - - - - - -I- - I Q L s"W� _ _ ` s s s SDMH #1 �6�• / 3. INSTALL TEMPORARY POND #3 (PRIVATE) PER DETAIL, C"-4 J - - - - - - INLET #2 °' I 3 I \ 48"0 SDMH FLAT TOP THIS SHEET. 10'Lx10'Wx2'D _ACHD SD-601, TYPE I - - - - - - - - - - - - I I -- - INLET #4 _ - _ \RIM:2572.61 s ° TOP ELEV:2572.65 � I V _ I RIM:2573.59 - - - - - - � - �-- - - - - - - - - - - - - - - ACHD SD-601, TYPE I_ _ \ -INV SUMP:2570.14 I I I I RIM:2573.57 \ INV IN:2570.01 12" (S) TOE ELEV:2570.65 O 3 ° a L INV OUT:2571.14 12" (S) L - - J SUMP:2569.82 \INV OUT:2570.01 18" (SW) DESIGN INFILTRATION RATE = 2 IN/HR z z / 00 16.7' -12" ADS N-12 HP I INV OUT:2570.82 12" (SW) / P� 8' VOLUME REQUIRED = 295 CIFuj 6 �� � / l @ 0.84% I I 17.5' 12" ADS N-12 HP / 12.8' 12" ADS N-12 HP /a'S/ VOLUME PROVIDED = 346 CIFO 0 INV:2571.00 06 / \j j// a s 4. INSTALL TEMPORARY POND #4 (PRIVATE) PER DETAIL, - L u- THIS SHEET. 10'Lx10'Wx2'D Q > i ' O6 INV:2570.65 CITY OF MERIDIAN INLET #5 "W TOP ELEV:2572.65 4 / // a \ 0 / // ACHD SD-603, TYPE III EASEMENT PER INST. RIM:2573.92 TOE ELEV:2570.65 / - 0 Q No. 2022-072452 / Of j/// / SUMP:2570.56 $�� DESIGN INFILTRATION RATE = 2 IN/HR Q VOLUME REQUIRED 279 CIFz Of INV IN:2570.64 12" (SE) m / S 5 =� $ a VOLUME PROVIDED = 346 CIF :5 - S INV OUT:2570.56 12" (N) ° 5. RETAIN AND PROTECT STORM DRAIN PIPES AND SEEPAGE N BED. REFER TO EXISTING CONDITIONS AND DEMOLITION s �2 / ��/ PLAN FOR ADDITIONAL PLANS. w Lu °s LJJ / \ / 6. INSTALL 12" METAL END SECTION AND TRASH RACK.CO A S Q Lu 1,v / / \\ \ U cc G. \ \\\ G CPA 00 Go co APPROXIMATE 100-YEAR CO TOP OF BANK WATER SURFACE ELEVATION PER PLAN 0 // \� \ \\ z 6" FREEBOARD MIN. N I_LENGTH/WIDTH VARIES 3'• /\//\//\//\� PER PLAN /\ LL z / ' N a TOE ELEVATION PER PLAN z / /\� \/ - ,\\\�\ ,\\�\\_/_ _ _ _ _SEASONA_L HIGH GROUNDWATER 18" MIN. ASTM C-33 /\\ / � ELEVATION J FILTER SAND/\\/\\/ / / / / / /\\/\\\� Z 3.0' MIN. BASIN SIDE SLOPES SHALL BE CONSTRUCTED O Z WITH 4" MIN. TOPSOIL OR AMENDED NATIVE E N G I N E E RING L.L Q MATERIAL. SEED MIXTURE SHALL BE DROUGHT 5725 NORTH DISCOVERY WAY TOLERANT PER LANDSCAPE PLANS. BOISE,IDAHO 83713 O o PHONE(208)639-6939 Z NOTES: kmengllp.com 1. CONTRACTOR SHALL OVER EXCAVATE TEMPORARY POND TO POORLY GRADED SAND WITH DESIGN BY: LCK GRAVEL MATERIAL. EXTEND SAND A MINIMUM OF 12" INTO FREE DRAINING MATERIAL SEE SOILS INVESTIGATION REPORT FOR FURTHER SOILS INFORMATION. DRAWN BY: LCK Q 2. CONTRACTOR SHALL NOTIFY ENGINEER IMMEDIATELY IF GROUNDWATER OR EVIDENCE OF GROUNDWATER IS ENCOUNTERED DURING CONSTRUCTION. CHECKED BY: LCK Q 0 3. CONTRACTOR TO CONTACT GEOTECHNICAL ENGINEER TO CONFIRM INFILTRATION RATES AT DATE: AUGUST 2023 z BOTTOM OF EACH SAND SECTION WITH A PERCOLATION TEST ONCE EXCAVATED. NOTIFY ENGINEER IMMEDIATELY IF INFILTRATION RATES ARE LESS THAN 4 INCHES PER HOUR. PROJECT: 23-084 SHEET NO. TEMPORARY POND C4.0 w SCALE: NTS 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 0.15 0.21 Basin B-1 10.0 0.15 0.21 Basin C-1 10.0 0.17 0.23 Basin D-11 10.0 1 0.16 1 0.22 Post-Development Runoff Volumes Required Storage Volume (CF) Basin A-1,Temporary Pond#1 262 Basin B-1,Temporary Pond#2 262 Basin C-1,Temporary Pond #3 295 Basin D-1,Temporary Pond#41 279 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. Steps for Peak Discharge Rate using the Rational M�1171ated for post-developme 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 TM Center Subdivision No.2-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) 4 Click to Show More Subbasins C Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 3,697 Acres 0.08 6 Determine the Weighted Runoff Coefficient(C) 0.95 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg1 0.95 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate to Min. Estimated Runoff Coefficients for Various Surface min - Type of Surface Runoff Coefficients"( 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 1.85 in/hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(QPeak) Qpeak 0.15 cfs Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 10 Calculate total runoff vol(V)(for sizing primary storage) V 200 ft3 Multi-family 0.60-0.75 V=CI(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 95th 0.60 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) err 174 ft' Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Parks,cemeteries 0. Playgrounds 0.20-0.0-0.35 5 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 0.95 Basin Forebay V 20 fts Concrete 0.95 Primary Treatment/StorageBasin V 180 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Gravel 0.75 Volume Without Sediment Factor(See BMP 20 Tab) V 200 ftj Fields:Sandy soil Soil Type Slope A B C D 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 O. Adapted from ASCE P:\23-084\Documents\Reports\Storm Drainage\Calcs\ACHD_SD_CALCS_112018.xism 6/27/2023,9:30AM Version 10.5,November 2018 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. �WPs for Peak Discharge Rate using the Rational M�1171ated for post-developme 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 TM Center Subdivision No.2-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 Click to Show More Subbasins C Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 3,697 Acres 0.08 6 Determine the Weighted Runoff Coefficient(C) 0.95 C=[(C1xAl)+(C2xA2)+(CnxAn)]/A Weighted AvgJ 0.95 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User calculate min 10 Min. Estimated Runoff Coefficients for Various Surface - Type of Surface Runoff Coefficients N 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 1.85 n/hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(QPeak) Qpe.k 0.15 cfs Urban neighborhoods 0.50-0.70 Residential 10 Calculate total runoff vol V far sizing V 200 ft3 Single Family 0.35-0.50 ( )( g primary storage) Multi-family 0.60-0.75 V=CI(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Enter Percentile Storm 195th percentile=0.60 in 95th Industrial and commercial ( p ) 0.60 In Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 174 ft' Heavy areas o.90 Parks,Cemeteries 0.10-0.25 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 0.95 Basin Forebay V 20 ft' Concrete 0.95 Primary Treatment/StorageBasin V 180 fts Brick 0.95 Subsurface Storage Roofs 0.95 Gravel 0.75 Volume Without Sediment Factor(See BMP 20 Tab) V 200 fts Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 o.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:\23-084\Documents\Reports\Storm Drainage\Calcs\ACHD_SD_CALCS_112018.xism 6/27/2023,9:31 AM Version 10.5,November 2018 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. �WPs for Peak Discharge Rate using the Rational M�1171ated for post-developme 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 TM Center Subdivision No.2-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 Click to Show More Subbasins C Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 4,129 Acres 0.09 6 Determine the Weighted Runoff Coefficient(C) 0.95 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted AvgJ 0.95 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User calculate min 10 Min. Estimated Runoff Coefficients for Various Surface - Type of Surface Runoff Coefficients N 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 1.85 n/hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(QPeak) Qpe.k 0.17 cfs Urban neighborhoods 0.50-0.70 Residential 10 Calculate total runoff vol V far sizing V 224 ft3 Single Family 0.35-0.50 ( )( g primary storage) Multi-family 0.60-0.75 V=CI(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Enter Percentile Storm 195th percentile=0.60 in 95th Industrial and commercial ( p ) 0.60 In Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 195 ft' Heavy areas o.90 Parks,Cemeteries 0.10-0.25 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 0.95 Basin Forebay V 22 ft' Concrete 0.95 Primary Treatment/StorageBasin V 201 fts Brick 0.95 Subsurface Storage Roofs 0.95 Gravel 0.75 Volume Without Sediment Factor(See BMP 20 Tab) V 224 fts Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 o.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:\23-084\Documents\Reports\Storm Drainage\Calcs\ACHD_SD_CALCS_112018.xism 6/27/2023,9:31 AM Version 10.5,November 2018 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. �WPs for Peak Discharge Rate using the Rational M�1171ated for post-developme 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 TM Center Subdivision No.2-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 Click to Show More Subbasins C Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 3,927 Acres 0.09 6 Determine the Weighted Runoff Coefficient(C) 0.95 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avgl 0.95 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User calculate min 10 Min. Estimated Runoff Coefficients for Various Surface - Type of Surface Runoff Coefficients N 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 1.85 n/hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(QPeak) Qpe.k 0.16 cfs Urban neighborhoods 0.50-0.70 Residential 10 Calculate total runoff vol V far sizing V 213 ft3 Single Family 0.35-0.50 ( )( g primary storage) Multi-family 0.60-0.75 V=CI(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Enter Percentile Storm 195th percentile=0.60 in 95th Industrial and commercial ( p ) 0.60 In Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 185 ft' Heavy areas o.90 Parks,Cemeteries 0.10-0.25 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 0.95 Basin Forebay V 21 ft' Concrete 0.95 Primary Treatment/StorageBasin V 191 fts Brick 0.95 Subsurface Storage Roofs 0.95 Gravel 0.75 Volume Without Sediment Factor(See BMP 20 Tab) V 213 fts Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 o.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:\23-084\Documents\Reports\Storm Drainage\Calcs\ACHD_SD_CALCS_112018.xism 6/27/2023,9:31 AM Version 10.5,November 2018 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. Steps for Peak Discharge Rate using the Rational M�1171ated for post-developme 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 TM Center Subdivision No.2-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) 4 Click to Show More Subbasins C Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 3,697 Acres 0.08 6 Determine the Weighted Runoff Coefficient(C) 0.95 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avgl 0.95 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate to Min. Estimated Runoff Coefficients for Various Surface min - Type of Surface Runoff Coefficients"( 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 in/hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(QPeak) Qpeak 0.21 cfs Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 10 Calculate total runoff vol(V)(for sizing primary storage) V 279 ft3 Multi-family 0.60-0.75 V=CI(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 95th 0.60 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) err 174 ft' Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Parks,cemeteries 0. Playgrounds 0.20-0.0-0.35 5 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 0.95 Basin Forebay V 28 fts Concrete 0.95 Primary Treatment/StorageBasin V 251 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Gravel 0.75 Volume Without Sediment Factor(See BMP 20 Tab) V 279 ftj Fields:Sandy soil Soil Type Slope A B C D 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 O. Adapted from ASCE P:\23-084\Documents\Reports\Storm Drainage\Calcs\ACHD_SD_CALCS_112018.xism 6/27/2023,9:28AM Version 10.5,November 2018 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. �WPs for Peak Discharge Rate using the Rational M�1171ated for post-developme 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 TM Center Subdivision No.2-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 Click to Show More Subbasins C Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 3,697 Acres 0.08 6 Determine the Weighted Runoff Coefficient(C) 0.95 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avgl 0.95 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User calculate min 10 Min. Estimated Runoff Coefficients for Various Surface - Type of Surface Runoff Coefficients N 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 n/hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(QPeak) Qpe.k 0.21 cfs Urban neighborhoods 0.50-0.70 Residential 10 Calculate total runoff vol V far sizing V 279 ft3 Single Family 0.35-0.50 ( )( g primary storage) Multi-family 0.60-0.75 V=CI(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Enter Percentile Storm 195th percentile=0.60 in 95th Industrial and commercial ( p ) 0.60 In Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 174 ft' Heavy areas o.90 Parks,Cemeteries 0.10-0.25 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 0.95 Basin Forebay V 28 ft' Concrete 0.95 Primary Treatment/StorageBasin V 251 fts Brick 0.95 Subsurface Storage Roofs 0.95 Gravel 0.75 Volume Without Sediment Factor(See BMP 20 Tab) V 279 fts Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 o.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:\23-084\Documents\Reports\Storm Drainage\Calcs\ACHD_SD_CALCS_112018.xism 6/27/2023,9:29 AM Version 10.5,November 2018 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. �WPs for Peak Discharge Rate using the Rational M�1171ated for post-developme 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 TM Center Subdivision No.2-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 Click to Show More Subbasins C Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 4,129 Acres 0.09 6 Determine the Weighted Runoff Coefficient(C) 0.95 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avgl 0.95 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User calculate min 10 Min. Estimated Runoff Coefficients for Various Surface - Type of Surface Runoff Coefficients N 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 n/hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(QPeak) Qpe.k 0.23 cfs Urban neighborhoods 0.50-0.70 Residential 10 Calculate total runoff vol V far sizing V 311 ft3 Single Family 0.35-0.50 ( )( g primary storage) Multi-family 0.60-0.75 V=CI(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Enter Percentile Storm 195th percentile=0.60 in 95th Industrial and commercial ( p ) 0.60 In Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 195 ft' Heavy areas o.90 Parks,Cemeteries 0.10-0.25 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 0.95 Basin Forebay V 31 ft' Concrete 0.95 Primary Treatment/StorageBasin V 280 fts Brick 0.95 Subsurface Storage Roofs 0.95 Gravel 0.75 Volume Without Sediment Factor(See BMP 20 Tab) V 311 fts Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 o.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:\23-084\Documents\Reports\Storm Drainage\Calcs\ACHD_SD_CALCS_112018.xism 6/27/2023,9:29 AM Version 10.5,November 2018 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. �WPs for Peak Discharge Rate using the Rational M�1171ated for post-developme 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 TM Center Subdivision No.2-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 Click to Show More Subbasins C Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 3,927 Acres 0.09 6 Determine the Weighted Runoff Coefficient(C) 0.95 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted AvgJ 0.95 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User calculate min 10 Min. Estimated Runoff Coefficients for Various Surface - Type of Surface Runoff Coefficients N 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 n/hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(QPeak) Qpe.k 0.22 cfs Urban neighborhoods 0.50-0.70 Residential 10 Calculate total runoff vol V far sizing V 296 ft3 Single Family 0.35-0.50 ( )( g primary storage) Multi-family 0.60-0.75 V=CI(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Enter Percentile Storm 195th percentile=0.60 in 95th Industrial and commercial ( p ) 0.60 In Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 185 ft' Heavy areas o.90 Parks,Cemeteries 0.10-0.25 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 0.95 Basin Forebay V 30 ft' Concrete 0.95 Primary Treatment/StorageBasin V 266 fts Brick 0.95 Subsurface Storage Roofs 0.95 Gravel 0.75 Volume Without Sediment Factor(See BMP 20 Tab) V 296 fts Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 o.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:\23-084\Documents\Reports\Storm Drainage\Calcs\ACHD_SD_CALCS_112018.xism 6/27/2023,9:29 AM Version 10.5,November 2018 TEMPORARY POND CALCULATIONS ACHD Calculation Sheet for Sizing Basins 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. User input in yellow cells. 1 Project Name TM Center Subdivision No.2-Basin A-1-Temporary Pond H1(Private) 2 Enter number of Basins(25 max) 4 3 Number of Cells(Forebay+primary=2,Primary 0nly=1) 1 4 Design Storm 100 Link to:LQV - 5 Weighted Runoff Coefficient C 0.95 QV2 QV3 6 Area A(Acres) 0.08 acres Q.V4 7 Approved Discharge Rate(if applicable) 0.00 cfs QV TR55 8 2-Prima ry Treatment/Storage V 279 ft3 Toggle between Forebay and Primary Basin,enter data and print for each sae�e Side S4ope z sit.stoma F Ore Ftmv P6w A W V sirs*e <--- > < > 94,Sim z < t �. Sib sir: Primary Basin 9 Select Primary Basin Shape 3-Rectangle 10 Width of Primary Basin Bottom W 10.0 ft 11 Length of Primary Basin Bottom L 10.0 ft 12 Side Slopes(H:1) HA 3.00 13 Enter Bottom Elevation 2571.00 ft 14 Enter Top Bank Elevation 2573.00 ft 15 Enter Water Surface Elevation(WSE) 2572.50 ft 16 Distance Between Forebay and Primary Basin(blank if na) 0.00 ft 17 Enter Elevation Berm 0.00 ft 18 Enter High Groundwater Elevation 2564.00 ft 19 Min.Freeboard Requirement 0.50 20 Freeboard Provided 21 Infiltration Area for Primary/Storage Basin Infiltration? 2.00 in/hr Note:infiltration required if Design Infiltration Rate,Enter 0 for no infiltration bottom slope<1%or 0 outflow 22 Infiltration Area for Primary Asand 100 ftz Enter 0 for no infiltration 23 Adjusted Storage Required Storm Duration i total Pre-Dev Total Max Vol Q Runoff Vol Perc Vol Discharge Discharge Reqd Min Fir in/hr cfs ft3 ft3 ft3 ft3 ft3 60 1.00 0.96 0.08 279 17 0 17 262 24 Depth-Storage Relationship: Saved Surface Basin Basin Surface Surface Area A at Volume Saved Stage Side Slope Width at Length at Area A at Area A at Stage(ft) Below Stage (ft) New Stage(ft) (H:V) Stage(ft) Stage(ft) Stage(ft) Stage(ft) OVERIDE (ft3) 2571.00 2571.00 3.000 10.0 10.0 100 0 2572.50 2572.50 3.000 19.0 19.0 361 346 1.50 ft depth for storage STORAGE OK 25 Does primary/storage basin have capacity? 26 Time to drain primary/storage basin 15.0 hours 90%volume in 48-hours minimum - P:\23-084\Documents\Reports\Storm Drainage\Calcs\ACHD_SD_CALCS_112018.xism 6/27/2023,9:31 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Basins 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. User input in yellow cells. 1 Project Name TM Center Subdivision No.2-Basin B-1-Temporary Pond#2(Private) 2 Enter number of Basins(25 max) 4 3 Number of Cells(Forebay+primary=2,Primary Only=1) 1 4 Design Storm 100 Link to: QV 5 Weighted Runoff Coefficient C 0.95 [QV2 QV3 6 Area A(Acres) 0.08 acres QV4 7 Approved Discharge Rate(if applicable) 0.00 cfs QV TR55 8 2-Prima ry Treatment/Storage V 279 ft3 Toggle between Forebay and Primary Basin,enter data and print for each sae�e Side S4ope z sit.stoma F Floe Ftmv P6w A W V s*e <--- > < > 94,Sim z < t �. Sib sir: Primary Basin 9 Select Primary Basin Shape 3-Rectangle 10 Width of Primary Basin Bottom W 10.0 ft 11 Length of Primary Basin Bottom L 10.0 ft 12 Side Slopes(H:1) HA 3.00 13 Enter Bottom Elevation 2571.00 ft 14 Enter Top Bank Elevation 2573.00 ft 15 Enter Water Surface Elevation(WSE) 2572.50 ft 16 Distance Between Forebay and Primary Basin(blank if na) 0.00 ft 17 Enter Elevation Berm 0.00 ft 18 Enter High Groundwater Elevation 2564.00 ft 19 Min.Freeboard Requirement 0.50 20 Freeboard Provided 21 Infiltration Area for Primary/Storage Basin Infiltration? 2.00 in/hr Note:infiltration required if Design Infiltration Rate,Enter 0 for no infiltration bottom slope<1%or 0 outflow 22 Infiltration Area for Primary Asand 100 ftz Enter 0 for no infiltration 23 Adjusted Storage Required Storm Duration i total Pre-Dev Total Max Vol Q Runoff Vol Perc Vol Discharge Discharge Reqd Min Hr in/hr cfs ft3 ft3 ft3 ft3 ft3 60 1.00 0.96 0.08 279 17 0 17 262 24 Depth-Storage Relationship: Saved Surface Basin Basin Surface Surface Area A at Volume Saved Stage Side Slope Width at Length at Area A at Area A at Stage(ft) Below Stage (ft) New Stage(ft) (H:V) Stage(ft) Stage(ft) Stage(ft) Stage(ft) OVERIDE (ft) 2571.00 2571.00 3.000 10.0 10.0 100 0 2572.50 2572.50 3.000 19.0 19.0 361 346 1.50 ft depth for storage STORAGE OK 25 Does primary/storage basin have capacity? 26 Time to drain primary/storage basin 15.0 hours 90%volume in 48-hours minimum - P:\23-084\Documents\Reports\Storm Drainage\Calcs\ACHD_SD_CALCS_112018.xism 6/27/2023,9:32 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Basins 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. User input in yellow cells. 1 Project Name TM Center Subdivision No.2-Basin C-1-Temporary Pond#3(Private) 2 Enter number of Basins(25 max) 4 3 Number of Cells(Forebay+primary=2,Primary Only=1) 1 4 Design Storm 100 Link to: QV 5 Weighted Runoff Coefficient C 0.95 QV2 [QV3 6 Area A(Acres) 0.09 acres QV4 7 Approved Discharge Rate(if applicable) 0.00 cfs QV TR55 8 2-Prima ry Treatment/Storage V 311 ft Toggle between Forebay and Primary Basin,enter data and print for each *L * str.Ftmv ArW e <--- > < C > 94,sip z L< �. Sib sir: Primary Basin 9 Select Primary Basin Shape 3-Rectangle 10 Width of Primary Basin Bottom W 10.0 ft 11 Length of Primary Basin Bottom L 10.0 ft 12 Side Slopes(H:1) HA 3.00 13 Enter Bottom Elevation 2570.65 ft 14 Enter Top Bank Elevation 2572.65 ft 15 Enter Water Surface Elevation(WSE) 2572.15 ft 16 Distance Between Forebay and Primary Basin(blank if na) 0.00 ft 17 Enter Elevation Berm 0.00 ft 18 Enter High Groundwater Elevation 2564.00 ft 19 Min.Freeboard Requirement 0.50 20 Freeboard Provided 21 Infiltration Area for Primary/Storage Basin Infiltration? 2.00 in/hr Note:infiltration required if Design Infiltration Rate,Enter 0 for no infiltration bottom slope<1%or 0 outflow 22 Infiltration Area for Primary Asand 100 ftz Enter 0 for no infiltration 23 Adjusted Storage Required Storm Duration i total Q Runoff Vol Perc Vol Pre-Dev Total Max Vol Discharge Discharge Reqd Min Fir in/hr cfs ft3 ft3 ft3 ft3 ft3 60 1.00 0.96 0.09 311 17 0 17 295 24 Depth-Storage Relationship: Saved Surface Basin Basin Surface Surface Area A at Volume Saved Stage Side Slope Width at Length at Area A at Area A at Stage(ft) Below Stage (ft) New Stage(ft) (H:V) Stage(ft) Stage(ft) Stage(ft) Stage(ft) OVERIDE (ft) 2570.65 2570.65 3.000 10.0 10.0 100 0 2572.15 3.000 19.0 19.0 361 346 1.50 ft depth for storage STORAGE OK 25 Does primary/storage basin have capacity? 26 Time to drain primary/storage basin 16.8 hours 90%volume in 48-hours minimum - P:\23-084\Documents\Reports\Storm Drainage\Calcs\ACHD_SD_CALCS_112018.xlsm 7/14/2023,10:15 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Basins 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. User input in yellow cells. 1 Project Name TM Center Subdivision No.2-Basin D-1-Temporary Pond#4(Private) 2 Enter number of Basins(25 max) 4 3 Number of Cells(Forebay+primary=2,Primary 0nly=1) 1 4 Design Storm 100 Link to: QV - 5 Weighted Runoff Coefficient C 0.95 QV2 QV3 6 Area A(Acres) 0.09 acres [QV4 7 Approved Discharge Rate(if applicable) 0.00 cfs QV TR55 8 2-Prima ry Treatment/Storage V 296 ft Toggle between Forebay and Primary Basin,enter data and print for each *L * str.Ftmv ArW e <--- > < C > 94,sip z L< �. Sib sir: Primary Basin 9 Select Primary Basin Shape 3-Rectangle 10 Width of Primary Basin Bottom W 10.0 ft 11 Length of Primary Basin Bottom L 10.0 ft 12 Side Slopes(H:1) HA 3.00 13 Enter Bottom Elevation 2570.65 ft 14 Enter Top Bank Elevation 2572.65 ft 15 Enter Water Surface Elevation(WSE) 2572.15 ft 16 Distance Between Forebay and Primary Basin(blank if na) 0.00 ft 17 Enter Elevation Berm 0.00 ft 18 Enter High Groundwater Elevation 2564.00 ft 19 Min.Freeboard Requirement 0.50 20 Freeboard Provided 21 Infiltration Area for Primary/Storage Basin Infiltration? 2.00 in/hr Note:infiltration required if Design Infiltration Rate,Enter 0 for no infiltration bottom slope<1%or 0 outflow 22 Infiltration Area for Primary Asand 100 ftz Enter 0 for no infiltration 23 Adjusted Storage Required Storm Duration i total Pre-Dev Total Max Vol Q Runoff Vol Perc Vol Discharge Discharge Reqd Min Fir in/hr cfs ft3 ft3 ft3 ft3 ft3 60 1.00 0.96 0.08 296 17 0 17 279 24 Depth-Storage Relationship: Saved Surface Basin Basin Surface Surface Area A at Volume Saved Stage Side Slope Width at Length at Area A at Area A at Stage(ft) Below Stage (ft) New Stage(ft) (H:V) Stage(ft) Stage(ft) Stage(ft) Stage(ft) OVERIDE (ft) 2570.65 2570.65 3.000 10.0 10.0 100 0 2572.15 3.000 19.0 19.0 361 346 1.50 ft depth for storage STORAGE OK 25 Does primary/storage basin have capacity? 26 Time to drain primary/storage basin 16.0 hours 90%volume in 48-hours minimum - P:\23-084\Documents\Reports\Storm Drainage\Calcs\ACHD_SD_CALCS_112018.xism 7/14/2023,10:16 AM Version 10.5,November 2018 APPENDIX D - GEOTECHNICAL ENGINEERING REPORT MATERIALS 7 August 2019 TESTING & Page# 1 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Mr.Jon Wardle Brighton Corporation 2929 West Navigator Drive Meridian, ID 83642 208-378-4000 Re: Limited Geotechnical Engineering Report TM Center Development Ten Mile Road and Cobalt Drive Meridian, ID Dear Mr. Wardle: In compliance with your instructions, MTI has conducted a limited soils exploration and pavement evaluation for the above referenced development. Fieldwork for this investigation was conducted on 22 July 2019. The proposed development is in the southwestern portion of the City of Meridian, Ada County, ID, and occupies portions of the S%2NW'/4 and SWl/4NE1/4 of Section 14,Township 3 North,Range 1 West,Boise Meridian. This project will consist of construction of roadways throughout the proposed development. 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 Hunter Hayes of Materials Testing and Inspection (MTI), on 11 July 2019. Said authorization is subject to terms, conditions, and limitations described in the Professional Services Contract entered into between Brighton Corporation and MTL Our scope of services for the proposed development has been provided in our proposal dated 11 July 2019 and repeated below. 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 design or earthwork recommendations. 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. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page#2 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections 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"Sandy Alluvium of Side-Stream Valleys and Gulches" as mapped by Othberg and Stanford (1993). Locally, these deposits are composed of medium to coarse sand interbedded with silty fine sand and silt and are mostly derived from weathered granite and reworked Tertiary sediments of the Boise Foothills. The thickness of this unit is variable. Because of the relative youthfulness of these deposits they contain only minor pedogenic clay and calcium carbonate. General Site Characteristics This proposed development consists of relatively flat and level to moderately sloping terrain. The site is bisected from the west to the east by the Kennedy Lateral. In the northwestern portion of the site near the intersection of Cobalt Drive and Wayfinder Avenue, the Kennedy Lateral is piped below ground. To the south of Cobalt Drive, the surface slopes downwards to an agricultural field at roughly 2 feet horizontal to 1 foot vertical (2:1). Throughout the majority of the site, surficial soils consist of lean clays with sand. Vegetation primarily consists of agricultural crops, bunchgrass, and other native grass varieties typical of and to semi-arid environments. Regional drainage is north and west toward the Boise River. Stormwater drainage for the site is achieved by both sheet runoff and percolation through surficial soils. Runoff predominates for the steeper slopes while percolation prevails across the gently sloping and near level areas. From the north, intermittent off-site stormwater may drain onto the project site. Stormwater drainage collection and retention systems are not in place on the project site, but are planned as part of the development. 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 pit locations were staked in the field by Mr. Kameron Nauhi of Brighton Corporation. Actual test pit sites were located in the field by means of a Global Positioning System (GPS) device and are reportedly accurate to within fifteen 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 Enclosures section. Results of field and laboratory tests are also presented in the Enclosures section. MTI recommends that these logs not be used to estimate fill material quantities. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 3 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections 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 Enclosures section. The laboratory testing program for this report included: Atterberg Limits Testing—ASTM D4318, Grain Size Analysis—ASTM C 117/C 136, and Resistance Value (R-value) and Expansion Pressure of Compacted Soils—Idaho T-8. 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 Enclosures section. The materials encountered during exploration were quite typical for the geologic area mapped as Sandy Alluvium of Side-Stream Valleys and Gulches. Lean clay with gravel fills were observed at ground surface in test pit 1. These materials were brown, dry, and very stiff,with fine to medium-grained sand and fine to coarse gravel. Native lean clay with sand soils were encountered at ground surface in the remaining test pits. These soils were brown, dry to slightly moist, and stiff to hard, with fine to medium-grained sand. Plow zones and organics were noted to depths of up to 1.4 feet bgs. Sandy silt soils were encountered beneath lean clays with sand in test pits 2 and 5. These soils were light brown to brown, dry to slightly moist, and hard, with fine to medium-grained sand. Weak to moderate calcic cementation was encountered within the upper portions of this horizon. Silty sand with gravel sediments were found beneath lean clays with sand in test pit 3. These sediments were light brown,dry to slightly moist,and dense,with fine to coarse-grained sand and fine to coarse gravel. Varying layers of poorly graded gravel with silt and sand, poorly graded gravel with clay and sand, clayey gravel with sand, and poorly graded gravel with sand sediments were encountered at depth in the test pits. These sediments were tan to brown or red-brown, dry to saturated, and medium dense to very dense, with 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. Groundwater During this field investigation, groundwater was encountered in test pits at depths ranging from 8.0 to 13.6 feet bgs. Soil moistures in the test pits were generally dry to slightly moist within surficial soils. Within the poorly graded gravels with sand,poorly graded gravels with silt and sand, and clayey gravels with sand, soil moistures graded from dry to saturated as the water table was approached and penetrated. In the vicinity of the project site, groundwater levels are controlled in large part by agricultural and commercial irrigation activity and leakage from the Kennedy Lateral. Maximum groundwater elevations likely occur during the later portion of the irrigation season. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page#4 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections MTI has previously performed 14 geotechnical investigations within 0.48 mile of the project site. Information from these investigations has been provided in the table below. Groundwater Data Date Approximate Distance Direction from Site Groundwater Depth from Site feet feet bgs) October 2013 0.15 South 12.5 to 15.5 December 2016 0.30 South 15.7 February 2017 0.20 Northwest Not Encountered to 16.5 February 2017 0.39 South 7.0 to 7.4 February 2017 0.46 South 6.6 to 11.8 March 2017 0.20 East 5.7 to 6.4 June 2017 0.07 Southwest 9.5 to 15.2 June 2017 0.22 Northwest 12.5 to 15.5 December 2017 0.44 South 5.5 October 2018 0.12 North Not Encountered to 15.4 October 2018 0.21 Northwest Not Encountered to 15.4 December 2018 0.31 Southeast 14.8 February 2019 0.39 Southwest 8.9 April 2019 0.48 Southeast 7.2 to 8.7 Furthermore, according to groundwater monitoring data collected by MTI within approximately 1/2-mile of the project site, groundwater was measured at depths ranging between 5.1 to 11.5 feet bgs. Based on evidence of this investigation and background knowledge of the area, MTI estimates groundwater depths to remain greater than approximately 4.5 feet bgs throughout the year. Since this is an estimated depth and seasonal groundwater levels fluctuate, actual levels should be confirmed by periodic groundwater data collected from piezometers installed in the test pits. If desired, MTI is available to perform this 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, lean clay 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; though calcium carbonate cementation may reduce this value to near zero. Clayey gravel with sand and poorly graded gravel with clay and sand sediments typically have infiltration rates ranging from 2 to 6 inches per hour. Silty sand with gravel sediments usually display rates of 4 to 8 inches per hour. Poorly graded gravel with sand and poorly graded gravel with silt and sand sediments typically exhibit infiltration values in excess of 12 inches per hour. Due to the variability of soil types encountered throughout the site, MTI recommends that infiltration testing be performed once the infiltration facility locations have been determined. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 5 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Recommended Pavement Sections MTI has used traffic indexes of 6 and 8 to determine the necessary pavement cross-sections 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 1.5 to 2.0 feet below existing ground surface. This sample, consisting of lean clay with sand collected from test pit 3, yielded a R-value of less than 5. A R-value of 4 was used for design calculations. 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. 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 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' Roadway Section Roadway Section 'r1l. h< TI:8 Asphaltic Concrete 2.5 Inches 3.5 Inches Crushed Aggregate Base 4.0 Inches 6.0 Inches Structural Subbase 14.0 Inches 18.0 Inches Compacted Subgrade See Pavement Subgrade See Pavement Subgrade Preparation Section Preparation Section 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. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 6 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Pavement Subgrade Preparation Uncontrolled fill and plow zones, which should be treated as uncontrolled fill, was encountered in portions of the site. MTI recommends that these materials be excavated to a sufficient depth to expose competent, native soils. MTI personnel must be present during excavation to identify these materials. Native clay soils are moderately plastic and will be susceptible to shrink/swell movements associated with moisture changes. The clay soils (if exposed) should be scarified to a depth of 6 inches and compacted between 92 to 98 percent of the maximum dry density as determined by ASTM D698. The moisture content should be within 2 percent of optimum. Structural fill should be placed as soon as possible after compaction of clay soils in order to limit moisture loss within the upper clays. 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. Subgrade clayey soils near and above optimum moisture contents may pump during compaction. Pumping or soft areas must be removed and replaced with structural fill. Fill material and aggregates as well as compacted native subgrade soils,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 D1557 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. 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. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 7 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections • 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. • 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 1%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. 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. However, use of silty soils (GM, SM, and MQ as structural fill below footings is prohibited. 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 closely 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 Pavement Subgrade Preparation section and Common Pavement Section Construction Issues 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. 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 D1557. • Below Flexible Pavements: A minimum of 92 percent of the maximum dry density as determined by ASTM D 1557 or 95 percent of the maximum dry density as determined by ASTM D698. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 8 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections The ASTM D 15 57 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. 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("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 Subject 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. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 9 of 21 ap INSPECTION b 191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections 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. 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 II/III 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. General Comments Based on the subsurface conditions encountered during this investigation and available information regarding the proposed pavements, the site is adequate for the planned construction. When plans and specifications are complete, and if significant changes are made in the character or location of the proposed pavements, consultation with MTI must be arranged as supplementary recommendations may be required. 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. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 august 2019 TESTING & Page# 10 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ 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, A Materials Testing & Inspection oNrvsFoNU/�h 14898 13 8/7/2019 0 41- OF \) Clint Wyllie, G.I.T. Reviewed by: Eli abeth Brown, P.E. ��4 BET H BRO Staff Geologist Geotechnical Services Manager Enclosures: Geotechnical General Notes Geotechnical Investigation Test Pit Logs Gravel Equivalent Method—Pavement Thickness Design Procedures R-value Laboratory Test Data Vicinity Map Site Map 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 11 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL GENERAL NOTES 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 Cementation Description Field Test Description Field Test Dry Absence of moisture,dusty,dry to touch Weakly Crumbles or breaks with handling or slight finger pressure Moist Damp but not visible moisture Moderately Crumbles or beaks with considerable finger pressure Wet Visible free water,usually soil is below Strongly Will not crumble or break with finger water table g 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 Majo ivisions Symbol Soil Descriptions Gravel&Gravelly GW Well-graded gravels; gravel/sand mixtures with little or no fines Soils GP Poorly-graded gravels; gravel/sand mixtures with little or no fines Coarse-Grained <50% coarse fraction GM Silty gravels;poorly-graded gravel/sand/silt mixtures Soils passes No.4 sieve GC Clayey gravels;poorly-graded gravel/sand/clay mixtures <50% passes No.200 Sand&Sandy SW Well-graded sands;gravelly sands with little or no fines sieve Soils SP Poorly-graded sands;gravelly sands with little or no fines >50% coarse fraction SM Silty sands;poorly-graded sand/gravel/silt mixtures passes No.4 sieve SC Clayey sands;poorly-graded sand/gravel/clay mixtures ML Inorganic silts;sandy,gravelly or clayey silts Silts&Clays CL Lean clays;inorganic,gravelly,sandy,or silty,low to medium-plasticity clays Fine Grained LL<50 Soils>50% OL Organic,low-plasticity clays and silts passes No.200 MH Inorganic,elastic silts;sandy, gravelly or clayey elastic silts sieve Silts&Clays LL>50 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 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 12 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-1 Date Advanced: 22 July 2019 Logged by: Hunter Hayes, E.I. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Latitude: 43.598784 Longitude: -116.432559 Depth to Water Table: 9.0 Feet bgs Total Depth: 13.5 Feet bgs Notes: Piezometer installed to 13.5 feet bgs. Depth Field Description and USCS Soil and Sample Sample Depth Lab Feet bgs) Sediment Classification Type Feet bgs) Qp Test ID Lean Clay with Gravel Fill (CL-FILL): 0.0-1.3 Brown, dry, very stiff, with fine to medium- 2.5-3.0 rained sand and fine to coarse gravel. Poorly Graded Gravel with Silt and Sand 1.3-9.9 (GP-GM): Tan to light brown, dry to slightly moist, dense, with fine to coarse-grained sand and 6-inch-minus cobbles. Poorly Graded Gravel with Clay and Sand 9.9-13.5 (GP-GC):Brown, slightly moist to saturated, dense, with fine to coarse-grained sand and 6-inch-minus cobbles. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtl mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 13 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-2 Date Advanced: 22 July 2019 Logged by: Hunter Hayes, E.I. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Latitude: 43.601206 Longitude: -116.432155 Depth to Water Table: 13.6 Feet bgs Total Depth: 15.2 Feet bgs Notes: Piezometer installed to 15.2 feet bgs. Depth Field Description and USCS Soil and Sample Sample Depth Lab Feet bgs) Sediment Classification Type Feet bgs) Qp Test ID Lean Clay with Sand (CL): Brown, dry, very 0.0-1.4 stiff to hard, with fine to medium-grained 3.0-4.5+ sand. --Plow zone and organics noted throughout. Sandy Silt(ML):Light brown, dry to slightly moist, hard, with fine to medium-grained 1.4-4.0 sand. --Moderate calcic cementation encountered from 1.4 to 2.4 eet bgs. Poorly Graded Gravel with Sand (GP): Light brown, slightly moist to saturated, medium 4.0-15.2 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 Copyrighterials www.mti-id.com•mtl mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 14 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-3 Date Advanced: 22 July 2019 Logged by: Hunter Hayes, E.I. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Latitude: 43.598915 Longitude: -116.429619 Depth to Water Table: 8.0 Feet bgs Total Depth: 13.2 Feet bgs Notes: Piezometer installed to 13.2 feet bgs. Depth Field Description and USCS Soil and Sample Sample Depth Lab Feet bgs) Sediment Classification Type Feet bgs) Qp Test ID Lean Clay with Sand(CL):Brown, dry, hard, with fine to medium-grained sand. A 0.0-2.1 --plow zone and organics noted to 0.9 foot Bulk 1.5-2.0 4.5+ R-value bgs- Silty Sand with Gravel (SM): Light brown, 2.1-3.3 dry to slightly moist, dense, with fine to caorse-grained sand and fine to coarse ravel. Poorly Graded Gravel with Silt and Sand (GP-GM): Tan to light brown, slightly moist 3.3-11.7 to saturated, medium dense, with fine to coarse-grained sand and 4-inch-minus cobbles. --Some clay content noted throughout. Clayey Gravel with Sand (GC): Red-brown, 11.7-13.2 saturated, dense to very dense, with fine to coarse-grained sand and 4-inch-minus cobbles. Lab Test ID M LL PI Sieve Analysis % - - #10 #40 #100 #200 A 9.9 40 22 100 99 93 89 83.8 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 15 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-4 Date Advanced: 22 July 2019 Logged by: Hunter Hayes, E.I. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Latitude: 43.601071 Longitude: -116.423327 Depth to Water Table: 11.1 Feet bgs Total Depth: 14.5 Feet bgs Notes: Piezometer installed to 14.5 feet bgs. Depth Field Description and USCS Soil and Sample Sample Depth Lab Feet bgs) Sediment Classification Type Feet bgs) Qp Test ID Lean Clay with Sand (CL): Brown, dry, very 0.0-1.3 stiff to hard, with fine-grained sand. 3.5-4.5+ --Plow zone and organics noted throughout. Poorly Graded Gravel with Clay and Sand 1.3-10.4 (GP-GC): Tan to brown, dry to moist, dense, with fine to coarse-grained sand and 6-inch- minus cobbles. Clayey Gravel with Sand(GC):Brown, moist 10.4-14.5 to saturated, dense to very dense, with fine to coarse-grained sand and 6-inch-minus cobbles. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtl mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 16 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-5 Date Advanced: 22 July 2019 Logged by: Hunter Hayes, E.I. Excavated by: Struckman's Backhoe Service Location: See Site Map Plates Latitude: 43.597464 Longitude: -116.423903 Depth to Water Table: 10.7 Feet bgs Total Depth: 14.0 Feet bgs Notes: Piezometer installed to 14.0 feet bgs. Depth Field Description and USCS Soil and Sample Sample Depth Lab Feet bgs) Sediment Classification Type Feet bgs) Qp Test ID Lean Clay with Sand (CL): Brown, dry to slightly moist, stiff to very stiff, with fine- 0.0-2.2 grained sand. 1.5-2.5 --Plow zone and organics noted to 1.0 foot bgs. Sandy Silt (ML): Light brown to brown, dry to slightly moist, hard, with fine to medium- 2.2-5.1 grained sand. --Weak to moderate calcic cementation encountered from 2.5 to 3.1 feet bgs. Poorly Graded Gravel with Silt and Sand (GP-GM): Light brown to brown, slightly 5.1-9.9 moist to moist, dense to very dense, with fine to coarse-grained sand and 6-inch-minus cobbles. Clayey Gravel with Sand (GC): Red-brown, 9.9-14.0 moist to saturated, very dense, with fine to coarse-grained sand and 6-inch-minus cobbles. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtl mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 17 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GRAVEL EQUIVALENT METHOD—PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: TM Center Development,Roadways Average Daily Traffic Count: All Lanes&Both Directions Design Life: 20 Years Traffic Index: 6.00 Climate Factor: 1 R-Value of Subgrade: 4.00 Subgrade CBR Value: 2.25 Subgrade Mr: 3,375 R-Value of Aggregate Base: 80 R-Value of Granular Borrow. 60 Subgrade R-Value: 4 Expansion Pressure of Subgrade: 1.40 Unit Weight of Base Materials: 130 Total Design Life 18 kipESAL's: 33,131 ASPHALTIC CONCRETE: Gravel Equivalent,Calculated: 0.384 Thickness: 0.196923077 Use= 2.5 Inches Gravel Equivalent,ACTUAL: 0.41 CRUSHED AGGREGATE BASE Gravel Equivalent(Ballast): 0.768 Thickness: 0.329 Use= 4 Inches Gravel Equivalent,ACTUAL: 0.773 SUBBASE: Gravel Equivalent(Ballast): 1.943 Thickness: 1.070 Use= 14 hiches Gravel Equivalent,ACTUAL: 1.940 TOTAL Thickness: 1.708 Thickness Required by Exp.Pressure: 1.551 Design ACHD Depth Substitution Inches Ratios Asphaltic Concrete(at least 2.5): 2.50 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): 14.00 1.00 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtl mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 18 of 21 ap INSPECTION b191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GRAVEL EQUIVALENT METHOD—PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: TM Center Development Roadways Average Daily Traffic Count: All Lanes&Both Directions Design Life: 20 Years Traffic Index: 8.00 Climate Factor: 1 R-Value of Subgrade: 4.00 Subgrade CBR Value: 2.25 Subgrade Mr: 3,375 R-Value of Aggregate Base: 80 R-Value of Granular Borrow. 60 Subgrade R-Value: 4 Expansion Pressure of Subgrade: 1.40 Unit Weight of Base Materials: 130 Total Design Life 18 kipESAL's: 371,659 ASPHALTIC CONCRETE: Gravel Equivalent,Calculated: 0.512 Thickness: 0.262564103 Use= 3.5 Inches Gravel Equivalent,ACTUAL: 0.57 CRUSHED AGGREGATE BASE Gravel Equivalent(Ballast): 1.024 Thickness: 0.414 Use= 6 Inches Gravel Equivalent,ACTUAL: 1.119 SUBBASE: Gravel Equivalent(Ballast): 2.458 Thickness: 1.339 Use= 18 hiches Gravel Equivalent,ACTUAL: 2.619 TOTAL Thickness: 2.292 Thickness Required byExp.Pressure: 1.551 Design ACHD Depth Substitution Inches Ratios Asphaltic Concrete(at least 2.5): 3.50 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): 6.00 1.10 Subbase(at least 4.2): 18.00 1.00 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtl mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 7 August 2019 TESTING & Page# 19 of 21 INSPECTION b 191306g_limitedgeo AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections R-VALUE LABORATORY TEST DATA Source and Description: TP-3: 1.5'-2.0', Lean Clay with Sand Date Obtained: 22 July 2019 Sample ID: 19-7851 —Sampling and Preparation: ASTM D75: AASHTO T2: X ASTM D421: AASHTO T87: X Test Standard: ASTM D2844: AASHTO T190: Idaho T8: X Sample A B C Dry Density(lb/ft) NA NA NA Moisture Content %) NA NA NA Expansion Pressure (psi) NA NA NA Exudation Pressure (psi) NA NA NA R-Value NA NA NA R-Value @ 200 psi Exudation Pressure= Less than 5** **ASTM D2844 Note 2: Occasionally,material from very plastic clay-test specimens will extrude from under the mold and around the follower ram during the loading operation. If this occurs when the 800-psi point is reached and fewer than five lights are lighted, the soil should be reported as less than 5 R-value. R-Value @ Exudation Pressure 90.0 88.0 86.0 84.0 82.0 80.0 400 350 300 250 200 150 100 50 Exudation Pressure (psi) 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtl mti-id.com ght©2019 Inspection Testing&Inspection Z E N } Q a M _ x U V p oM@� Z W Npp � N 'I In � Q L m E' -0 p Q LL LL W Q � eZ ® C U co L Z a _ U) M fn N p co Ern_ d m a U Z E 04 N C 'O fn or Z O X O c6 d c c oMo a o w o .� Q CD Z w a o aci a`� o Q m ui RR N m uj w IL L 6. �o ca w u ,vf •= 1'EN MILE RED �I e C O 0 aZ � J LL z � z i= ® p Q l7 � -o-, M 0 aD N Yr z_ u U N 00 E y H ~W L W � �- �/� a o x E Ln Z LaLw in E - Q W N a eZ O o U H > U M G r = CD co O a) O T 67 m6 > co a5 Cc 0 0 N �' — ca E N c a> C 'a in iT g w w o o oa �j � � � >o O Z W a0 Q m a`) oQ `n co w o N m CL LO CL 1 I _ 1 1 - — — - � f I I � I I I I i i — C �� l , Q � J —___ ___-_____J ----------- __ I I f � I I -� TEN MILE ROAD MATERIALS 22 August 2019 TESTING & Page# I of 7 INSPECTION b191306g_add#1-revised AN ATLAS COMPANY LJ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections Mr.Jon Wardle Brighton Corporation 2929 West Navigator Drive Meridian, ID 83642 208-378-4000 Re: Addendum#1—Additional Pavement Recommendations-Revised TM Center Development Ten Mile Road and Cobalt Drive Meridian,ID Dear Mr. Wardle: This addendum report presents additional recommendations not requested at the time of the previously issued MTI Geotechnical Engineering Report (B191306g). 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 MTI has used traffic indexes of 6 and 8 to determine the necessary pavement cross-sections 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 2.2 to 2.5 feet below existing ground surface. This sample, consisting of sandy silt collected from test pit 5, yielded a R-value of 17. The R-value was converted to a CBR value of 7 for private roadway design. It is MTI's understanding that the surficial clay soils will be completely removed from beneath all pavements. 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 Section—Private Roadways The American Association of State Highway and Transportation Officials (AASHTO) design method has been used to calculate the following pavement section. A calculation sheet provided in the Enclosures section indicates the soils constant, traffic loading, traffic projections, and material constants used to calculate the pavement section. MTI recommends that materials used in the construction of asphaltic concrete pavements meet 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 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 22 August 2019 TESTING & Page#2 of 7 INSPECTION b191306g_add#1-revised AN ATLAS COMPANY LJ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections AASHTO Flexible Pavement Specifications Pavement Section Component' Driveways and Parking Private Roadways Asphaltic Concrete 2.5 Inches Crushed Aggregate Base 4.0 Inches Structural Subbase 6.0 Inches Compacted Subgrade See Pavement Subgrade Preparation Section 'It 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: Granular structural fill material complying with the requirements detailed in the Structural Fill section of this report except that the maximum material diameter is no more than 2/3 the component thickness. Gradation and suitability requirements shall be per Table 1, ISPWC. Flexible Pavement Sections—Public Roadways 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. Gravel Equivalent Method Flexible Pavement Specifications Pavement Section Component' Roadway Section Roadway Section TI:6 TI:8 Asphaltic Concrete 2.5 Inches 3.5 Inches Crushed Aggregate Base 4.0 Inches 6.0 Inches Structural Subbase 10.0 Inches 14.0 Inches Compacted Subgrade See Pavement Subgrade See Pavement Subgrade Preparation Section Preparation Section 'It will be required for MTI personnel to verify subgrade competency at the time of construction. 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 22 August 2019 TESTING & Page# 3 of 7 INSPECTION b191306g_add#1-revised AN ATLAS COMPANY LJ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections 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. Pavement Subgrade Preparation All uncontrolled fill materials, plow zones, and lean clay with sand soils must be completely removed. MTI personnel must be present to identify these materials in the field. 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. Subgrade silty soils near and above optimum moisture contents maypump during compaction. 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 D1557 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 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. ASS\0 NA L Fi�G Respectfully Submitted, Qo� \\C E NSFo Materials Testing & Inspection � 14919 8-22-19 Clint Wyllie, G.I.T. Reviewed by: Monica Saculles, P. 9TF OF Staff Geologist Senior Geotechnical E SACv�'�<`" Enclosures: AASHTO Pavement Thickness Design Procedures Gravel Equivalent Method Pavement Thickness Design Procedures R-Value Laboratory Test Data 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtI mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 22 August 2019 TESTING & Page#4 of 7 INSPECTION b191306g_add#1-revised AN ATLAS COMPANY LJ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections AASHTO PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: TM Center Development,Private Roadways Average Daily Traffic Count: 500 All Lanes&Both Directions Design Life: 20 Years Percent of Traffic in Design Lane: 50% Terminal Seviceability Index(Pt): 2.5 Level of Reliability: 95 Subgrade CBR Value: 7 Subgrade Mr: 10,500 Calculation of Design-18 ldp ESALs Daily Growth Load Design Traffic Rate Factors ESALs Passenger Cars: 233 2.0% 0.0008 1,653 Buses: 0 2.0% 0.6806 0 Panel&Pickup Trucks: 15 2.0% 0.0122 1,623 2-Axle,6-Tire Trucks: 1 2.0% 0.1890 1,676 Concrete Trucks: 1 2.0% 4.4800 29,798 Dump Trucks: 0 2.0% 3.6300 0 Tractor Semi Trailer Trucks: 0 2.0% 2.3719 0 Double Trailer Trucks 0 2.0% 2.3187 0 Heavy Tractor Trailer Combo Trucks: 0 2.0% 2.9760 0 Average Daily Traffic in Design Lane: 250 Total Design Life 18-kip ESALs: 34,750 Actual Log(ESALs): 4.541 Trial SN: 2.20 Trial Log(ESALs): 4.980 Pavement Section Design SN: 2.21 Design Depth Structural Drainage Inches Coefficient Coefficient Asphaltic Concrete: 2.50 0.42 n/a Asphalt-Treated Base: 0.00 0.25 n/a Cement-Treated Base: 0.00 0.17 n/a Crushed Aggregate Base: 4.00 0.14 1.0 Subbase: 6.00 0.10 1.0 Special Aggregate Subgrade: 0.00 0.09 0.9 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtl mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 22 August 2019 TESTING & Page# 5 of 7 INSPECTION b191306g_add#1-revised AN ATLAS COMPANY LJ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GRAVEL EQUIVALENT METHOD—PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: TM Center Development,Roadway Section,Local Streets Average Daily Traffic Count: All Lanes&Both Directions Design Life: 20 Years Traffic Index: 6.00 Climate Factor: 1 R-Value of Subgrade: 17.00 Subgrade CBR Value: 7 Subgrade Mr: 10,500 R-Value of Aggregate Base: 80 R-Value of Granular Borrow: 60 Subgrade R-Value: 17 Expansion Pressure of Subgrade: 0.29 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 Use= 2.5 Inches Gravel Equivalent,ACTUAL: 0.41 CRUSHED AGGREGATE BASE: Gravel Equivalent(Ballast): 0.768 Thickness: 0.329 Use= 4 hiches Gravel Equivalent,ACTUAL: 0.773 SUBBASE: Gravel Equivalent(Ballast): 1.594 Thickness: 0.821 Use= 10 Inches Gravel Equivalent,ACTUAL: 1.606 TOTAL Thickness: 1.375 Thickness Required by Exp.Pressure: 0.321 Design ACHD Depth Substitution Inches Ratios Asphaltic Concrete(at least 2.5): 2.50 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): 10.00 1.00 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtl mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 22 August 2019 TESTING & Page# 6 of 7 INSPECTION b191306g_add#1-revised AN ATLAS COMPANY LJ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections GRAVEL EQUIVALENT METHOD—PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: TM Center Development,Roadway Section,Collector Streets Average Daily Traffic Count: All Lanes&Both Directions Design Life: 20 Years Traffic Index: 8.00 Climate Factor: 1 R-Value of Subgrade: 17.00 Subgrade CBR Value: 7 Subgrade Mr: 10,500 R-Value of Aggregate Base: 80 R-Value of Granular Borrow: 60 Subgrade R-Value: 17 Expansion Pressure of Subgrade: 0.29 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= 3.5 Inches Gravel Equivalent,ACTUAL: 0.57 CRUSHED AGGREGATE BASE: Gravel Equivalent(Ballast): 1.024 Thickness: 0.414 Use= 6 hiches Gravel Equivalent,ACTUAL: 1.119 SUBBASE: Gravel Equivalent(Ballast): 2.125 Thickness: 1.006 Use= 14 Inches Gravel Equivalent,ACTUAL: 2.285 TOTAL Thickness: 1.958 Thickness Required by Exp.Pressure: 0.321 Design ACHD Depth Substitution Inches Ratios Asphaltic Concrete(at least 2.5): 3.50 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): 6.00 1.10 Subbase(at least 4.2): 14.00 1.00 2791 S Victory View Way•Boise,ID 83709•(208)376-4748• Fax(208)322-6515 Copyrighterials www.mti-id.com•mtl mti-id.com ght©2019 Inspection Testing&Inspection MATERIALS 22 August 2019 TESTING & Page# 7 of 7 INSPECTION b191306g_add#1 -revised AN ATLAS COMPANY ❑ Environmental Services ❑Geotechnical Engineering ❑Construction Materials Testing ❑Special Inspections R-VALUE LABORATORY TEST DATA Source and Description: TP-5: 2.2'-2.5', Sandy Silt Date Obtained: 19 August 2019 Sample ID: 19-7681 —Sampling and Preparation: ASTM D75: AASHTO T2: X ASTM D421: AASHTO T87: X Test Standard: ASTM D2844: AASHTO T190: Idaho T8: X Sample A B C Dry Density(lb/ft) 92.2 91.7 90.7 Moisture Content %) 25.5 27.1 27.9 Expansion Pressure (psi) 0.60 0.27 0.12 Exudation Pressure (psi) 386 188 127 R-Value 23 16 9 R-Value @ 200 psi Exudation Pressure= 17 R-Value @ Exudation Pressure 25.0 23.0 21.0 19.0 17.0 j 15.0 13.0 11.0 9.0 7.0 5.0 400 350 300 250 200 150 100 50 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 copy��Tegl Ling& nsp-tics Testing&Inspection