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HomeMy WebLinkAbout12. Stormwater Management Report V1ESE CONSULTANTS ESE Consultants, Inc. 3103 W. Sheryl Drive ENGINEERING • PLANNING - SURVEYING • ENVIRONMENTAL Meridian, Idaho 83642 TEL: 208-424-0020 STORMWATER MANAGEMENT REPORT FOR OAKS NORTH SUBDIVISION, PHASE 12 \0 AL FN vGEIV'q a z P-18043 �9 N9TF Pao .� �Q OF 0 . ma Mark R. Zarr'toW!�Jcy Professional Engineer Idaho License No. 18043 March 2022 Mmmimmmm LOCATED IN: CITY OF MERIDIAN ADA COUNTY, IDAHO TABLE OF CONTENTS SUBJECT Project Overview Stormwater Management Design Stormwater Equations SECTION 1 2 3 Primary Conveyance & Stormwater Facility Calculations 4 Intensity -Duration -Frequency Curve 5 Pipe Flow Calculations 6 Drainage Basin Map 7 SECTION 1 - Project Overview The Oaks North Subdivision No.12 is a part of a multi -phase residential development located in the City of Meridian, Ada County, Idaho. The development is situated along the north side of West McMillan Road, between North Black Cat Road and North McDermott Road. The applicant proposes to develop eighty-three (83) single family residential lots with this phase of the project on approximately 23.5 acres. The development includes the construction of homes and infrastructure to include roads, sidewalks, stormwater management facilities, utilities, and other improvements typical of residential construction. Additional improvements will be constructed as part of the subdivision in subsequent phases. Existing Conditions The project site is currently bounded by single family residential developments to the south (Oaks South Subdivision) and east (Jump Creek Subdivision). Existing farmland primarily bounds the project to the north and west. The project site itself is comprised of existing irrigated farmland with dirt access roads, field drains, and irrigation delivery ditches. There previously existed several outbuildings near McMillan Road that have been razed and removed from the site by the developer. The existing terrain is relatively flat with slopes generally less than one percent. The site slopes down gradient from east to west. Geotechnical Characteristics A Geotechnical Engineering Report was prepared by Materials Testing and Inspection (MTI) for the Oaks North Subdivision, dated July 20, 2018. The soils were generally described as having a hard pan layer at approximately 3-7 feet below the ground surface overlain by clay material. Gravel and sands were generally observed below the hard pan layer. Groundwater Groundwater monitoring of the project site was commenced by MTI in June 2018. A summary of the groundwater elevations observed on site to date have been recorded by MTI in the Groundwater Letter dated, November 20, 2019. The groundwater has been observed at depths between 3-ft and 10-ft below the ground surface. Soil Infiltration MTI performed soil infiltration tests at four locations within the project site and presented their results in Addendum #2 to the Geotechnical Engineering Report, dated February 8, 2019. Results of the soil infiltration rates ranged from a low of 0.24 in/hr to a high of more than 8 in/hr. An infiltration rate of 1 in/hr was utilized for design purposes. SECTION 2 - Stormwater Management Design Design Criteria The Stormwater Management Plan described herein has been designed according to the Ada County Highway District Policy Manual. The proposed Stormwater Management Design has been prepared to meet the following requirements and guidelines: ♦ The Rational Method (Q=CiA) has been utilized to calculate peak flows. Runoff coefficients were used per the ACHD Policy Manual. Rainfall intensities were determined using the ACHD adopted Intensity -Duration -Frequency Curve located in Section 5 of this report. Calculations for the requisite time of concentration (Tc) value are enclosed. The overland flow and gutter flow segments of the Tc were calculated based on the equations provided in the ACHD Policy Manual and enclosed within this report for reference. ♦ Pipe flow calculations are provided to demonstrate that the primary stormwater conveyance system is sized to adequately handle stormwater flows based on the 25-year storm event. ♦ The residential lot grading was designed to drain approximately the front half of the lot towards the street and is included in the stormwater basin calculations. Stormwater that falls within the back of the lots will be retained on site. Yard drains will be installed in the rear yards during home construction and final landscaping to facilitate infiltration of lot drainage. ♦ High groundwater observed through the site necessitated the use of a Vertical Sand Filter for the storage and infiltration of the 100-year storm event. An infiltration rate of 1 inch per hour has been used for the design of the vertical sand filter. A sand and grease trap is provided for pretreatment. ♦ Within Subdivision No.12 there are seven (7) proposed vertical sand filter noted as Basin A through Basin G. Basin A is located within Block 33 Common Lot 6C, Basin B is located in Block 33 Common Lot 17C, Basin C is located in the Northeast section of Block 35 Common Lot 6C, Basin D is located in Block 31 Common Lot 16C, Basin E located in Block 34 Common Lot 13C, Basin F located in Block 35 Common Lot 18C, and Basin G located in Block 12 Common Lot IOC. SECTION 3 - Stormwater Equations Stormwater Conveyance (ACHD Policy Manual 8011.2) - CIA where- - Discharge rate (ofs) D = Coefficient of Runoff (dimensionless) = Rainfall intensity (in/hr) for a duration equal to the time of concentration jr-) over the contributing area and for the design frequency. A = Site area (acres) Tc = Time of concentration Coefficient of Runoff (ACHD Policy Manual 8011.2.1) Estimated Runoff Coefficients for Various Surfaces Type of Surface Runoff Coefficients "' Business Downtown areas 0.70-0.95 Urbanneightwhoods 0.50.0.70 Residential SI ngle Family 0.35.0.50 Multifamily 0.60.0.75 Residential Iruralj 0.25.0.40 Apartment Dwelling Amzt a.70 Industrial and Commerri<. Light areas 0.80 Heavy areas 0.90 Parks,Cemeteries 0.10-0I5 Playgrounds 0.20-0.35 Rallroadyard areas 0.20.4.40 Unimproved areas 0.10.0 0 Streets Asphalt 0.95 -Concrete 0.95 Brick 0.95 Roofs 0.95 -Gravel 0.75 Flelds: Sandy sail Soll Type Slope A B C U Flat, 0.2% 0.04 0.07 0.11 0.1S Average, 2-6% 0.09 0.12 0.15 0.20 Steep, 96 0.13 0.18 0-23 0.� i Adapted from ASCE Design Storm Runoff Volume (ACHD Policy Manual 8011.3.2) V = CiA(3600) V: Design storm runoff volume required for storage C: Coefficient of Runoff is Rainfall Intensity per IDF Curve 1-hour 100-year storm event, i=0.96 1-hour 2-year storm event, i=0.26 A: Total catchment area (acres) Time of Concentration Tc = Tc-G + Tc-s Tc : Total time of concentration LG TC-G = 60 . VG Tc-G : Gutter time of concentration LG : Length of gutter flow VG : Gutter flow velocity VG=KukSP0.5 Ku : Empirical coefficient (3.281) k : Intercept coefficient (0.619) Sr : Slope (percent) 0.007(nL)0.8 TC-S = (p,)O.SSO.4 Tc-s : Overland time of concentration L : Length of overland (sheet) flow n : Manning's Roughness Coefficient (0.24) Pz : 2-year 24-hour rainfall (1.2 in.) S : Slope (ft/ft) Manning s Roughness Coefficient (ACHD Policy Manual 8011.5.3) Typical Lange of Manning's Coefficient (n) For Channels and Pipets, CoondUit Meterial r.lanninysn' Closed Conducts Concrete pipe 0.010 - 0,015 CMP Plastic (smooth) ROM - 0.015 Plastic oorru Doted 0.018 - D.M5 -PavemanUgutter secDons 0.012 - 0.016 Small Open Channels Concrete 0.011 - 0.015 Rtdbbla or npr 0-020 - 0-035 Vegetation 0.020 - 0.150 Bare Seel l 0.016 - 0.025 Rock Cut 0.025 - 0.045 Natural cKanreels {minor streams, lop width at Dow stage c30 rn (100 RD Fairly regurar seceiexe 0.025 - 0.050 Irregulattaotlw with PON2 1 0.040 - 0,150 'Lower values are usually far welFconstructad and mairnained {senrppthw) poses and channels Table 3-2. Manning's Roughness Coefficient (n) for Overland Sheet Flow.'S' Surface Description n Smooth asphalt 0.011 Smooth concrete 0.012 Ordinary concrete lining 0.013 Good wood 0.014 Brick with cement mortar 0.014 Vitrified clay 0.015 Cast iron 0.015 Corrugated metal pipe 0.024 Cement rubble surface 0.024 Fallow no residue 0.05 Cultivated soils Residue cover s 20% 0.06 Residue cover > 20% 0.17 Range (natural) 0.13 Grass Short grass prairie 0.15 Dense grasses 0.24 Bermuda grass 0.41 Woods` Light underbrush 0.40 Dense underbrush 0.80 'When selecting n, consider cover to a height of about 30 mm. This is only part of the plant cover that will obstruct sheet flow. SECTION 4 Primary Conveyance & Stormwater Facility Calculations BASIN CATCHMENT AREA A TIME OF CONCENTRATION Overland Flow Gutter Flow u a c men eng (ft) ope, s N Tc_s (min.) Elev I (ft) 1 Llev Z (ft) Length, LG (ft) Slope, Sp (%) Gutter (ft/sec) Tc_c (min.) Total Tc (min.) Al 67.0 1.00 22.3 2527.1 2526.5 152 0.41 1.30 2.0 24.3 CONVEYANCE Sub -Catchment C Area, A (acres) i2 (in/hr) i2s (in/hr) iloo (in/hr) Q2 (cfs) Q25 (cfs) Q100 (cfs) Al 0.50 0.44 0.44 1.16 1.61 0.10 0.26 0.35 Total 0.44 0.10 0.26 0.35 SAND & GREASE TRAP No. of S&G Baffle Throat Velocity, Velocity Vault Size Traps Spacing Throat Width Throat Area Flow Rate, Q25 V Flow Rate Check Check (galon) (inch) (inch) (ft) (cfs) (fps) Q2s < 3.33 cfs V < 0.5 fps 1000 1 20 48 6.67 0.26 0.04 TRUE TRUE STORAGE VOLUMES Chamber 1 Req'd Volume, Rock Void Volume, Storage Volume, V2_YR L1 W1 d1 Pipe Volume, VP1 VR1 V1 (ft) (ft) (ft) (ft) (ft) (ft) (ft) 206 50 3 4 87 205 292 Chamber 2 Req Volume, V100_ Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to YR L2 Wz d2 Pipe Volume, VP2 VR2 I Volume, V21 Volume, V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft) (in/hr) (ft) (ft) (hrs) 762 50 9.5 4 38 745 1.0 40 823 17.32 BASIN CATCHMENT AREA B TIME OF CONCENTRATION Overland Flow Gutter Flow Sub -Catchment engt (ft) ope, s (%) Tc_s (min.) ev (ft) Elev 2 (ft) Length, Lc (ft) ope, p M utter (ft/sec) Tc_G (min.) Total Tc (min.) B1 73.0 1.00 23.9 2529.4 2526.8 524 0.50 1.44 6.1 30.0 B2 63.0 1.00 21.2 2529.4 2526.8 524 0.50 1.44 6.1 27.3 CONVEYANCE Sub -Catchment C Area, A (acres) i2 (in/hr) i25 (in/hr) i100 (in/hr) Q2 (cfs) Q25 (cfs) Q100 (cfs) B1 0.50 2.39 0.41 1.08 1.51 0.49 1.29 1.80 32 0.50 1.40 0.42 1.11 1.55 0.29 0.77 1.08 Total 3.79 0.78 2.07 2.89 SAND & GREASE TRAP No. of S&G Baffle Throat Velocity, Velocity Vault Size Traps Spacing Throat Width Throat Area Flow Rate, Q25 V Flow Rate Check Check (galon) (inch) (inch) (ft) (cfs) (fps) Q2s < 3.33 cfs V < 0.5 fps 1000 1 20 48 6.67 2.07 0.31 TRUE TRUE STORAGE VOLUMES Chamber 1 Req'd Volume, Pipe Volume, Rock Void Volume, Storage Volume, V2-YR Ll Wl dl VP1 VR1 V1 (ft) (ft) (ft) (ft) (ft') (ft') (ft') 1,772 94 9.5 4.8 164 1,649 1,813 Chamber 2 Req Volume, V100- Pipe Volume, Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to YR L2 W2 d2 VP2 VR2 I Volume, V21 Volume, V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft) (in/hr) (ft) (ft) (hrs) 6,541 94 35 4.8 73 6,288 1.0 274 6,635 21.47 BASIN CATCHMENT AREA C TIME OF CONCENTRATION Overland Flow Gutter Flow Sub -Catchment engt (ft) ope, s (%) Tc_s (min.) ev (ft) Elev 2 (ft) Length, Lc (ft) ope, p M utter (ft/sec) Tc_G (min.) Total Tc (min.) C1 73.0 1.00 23.9 2529.4 2528.2 249 0.51 1.44 2.9 26.8 C2 65.0 1.00 21.8 2529.5 2528.2 285 0.48 1.41 3.4 25.2 CONVEYANCE Sub -Catchment C Area, A (acres) i2 (in/hr) i25 (in/hr) i100 (in/hr) Q2 (cfs) Q25 (cfs) Q100 (cfs) C1 0.50 1.05 0.42 1.12 1.55 0.22 0.59 0.81 C2 0.50 0.97 0.43 1.14 1.58 0.21 0.55 0.77 Tota 1 2.02 0.43 1.14 1.58 SAND & GREASE TRAP No. of S&G Baffle Throat Velocity, Velocity Vault Size Traps Spacing Throat Width Throat Area Flow Rate, Q25 V Flow Rate Check Check (galon) (inch) (inch) (ft) (cfs) (fps) Q2s < 3.33 cfs V < 0.5 fps 1000 1 20 48 6.67 1.14 0.17 TRUE TRUE STORAGE VOLUMES Chamber 1 Req'd Volume, Pipe Volume, Rock Void Volume, Storage Volume, V2-YR Ll Wl dl VP1 VR1 V1 (ft) (ft) (ft) (ft) (ft) (ft) (ft) 945 94 5.5 4.5 164 865 1,029 Chamber 2 Req Volume, V100- Pipe Volume, Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to YR L2 W2 d2 VP2 VR2 I Volume, V21 Volume, V2 Drain 90% (ft') (ft) (ft) (ft) (ft') (ft) (in/hr) (ft) (ft) (hrs) 3,489 94 20 4.5 73 3,355 1.0 157 3,584 20.05 BASIN CATCHMENT AREA D TIME OF CONCENTRATION Overland Flow Gutter Flow Sub -Catchment Length, (ft) Slope, s (%) Tc_S (min.) Elev 1 (ft) Elev 2 (ft) Length, LGSlope, (ft) Sp (%) butter (ft/sec) Tc_G (min.) Total Tc (min.) D1 70.0 1.00 23.1 2530.5 2527.6 337 0.86 1.89 3.0 26.1 D2 76.0 1.00 24.7 2530.5 2527.6 345 0.84 1.86 3.1 27.8 CONVEYANCE Sub -Catchment C Area, A (acres) i2 (in/hr) i25 (in/hr) iloo (in/hr) Q2 (cfs) Q25 (cfs) Q100 (cfs) D1 0.50 1.30 0.43 1.13 1.56 0.28 0.73 1.01 D2 0.50 1.60 0.42 1.11 1.54 0.34 0.89 1.23 Total 2.90 0.62 1.62 2.25 SAND & GREASE TRAP No. of S&G Baffle Throat Velocity, Velocity Vault Size Traps Spacing Throat Width Throat Area Flow Rate, Q25 V Flow Rate Check Check (galon) (inch) (inch) (ft) (cfs) (fps) Q25 < 3.33 cfs V < 0.5 fps 1000 1 20 48 6.67 1.62 0.24 TRUE TRUE STORAGE VOLUMES Chamber 1 Req'd Volume, Rock Void Volume, Storage Volume, V2_YR L1 W1 d1 Pipe Volume, VP1 VR1 V1 (ft) (ft) (ft) (ft) (ft) (ft) (ft) 1,358 94 8 4.3 164 1,228 1,392 Chamber 2 Req Volume, V100_ Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to YR L2 W2 d2 Pipe Volume, VP2 VR2 I Volume, V2i Volume, V2 Drain 90% (ft') (ft) (ft) (ft) (ft) (ft') (in/hr) (ft) (ft') (hrs) 5,013 94 30 4.3 73 4,821 1.0 235 5,129 19.20 BASIN CATCHMENT AREA E TIME OF CONCENTRATION Overland Flow Gutter Flow Sub -Catchment engt (ft) ope, s (%) Tc_s (min.) ev (ft) Elev 2 (ft) Length, Lc (ft) ope, p M utter (ft/sec) Tc_G (min.) Total Tc (min.) E1 93.0 1.00 29.0 2531.6 2528.9 169 1.59 2.56 1.1 30.1 E2 73.0 1.00 23.9 2531.6 2528.9 191 1.43 2.43 1.3 25.2 CONVEYANCE Sub -Catchment C Area, A (acres) i2 (in/hr) i25 (in/hr) i100 (in/hr) Q2 (cfs) Q25 (cfs) Q100 (cfs) E1 0.50 0.59 0.41 1.08 1.5 0.12 0.32 0.44 E2 0.50 0.72 0.43 1.14 1.58 0.15 0.41 0.57 Total 1.31 0.28 0.73 1.01 SAND & GREASE TRAP No. of S&G Baffle Throat Velocity, Velocity Vault Size Traps Spacing Throat Width Throat Area Flow Rate, Q25 V Flow Rate Check Check (galon) (inch) (inch) (ft) (cfs) (fps) Q2s < 3.33 cfs V < 0.5 fps 1000 1 20 48 6.67 0.73 0.11 TRUE TRUE STORAGE VOLUMES Chamber 1 Req'd Volume, Pipe Volume, Rock Void Volume, Storage Volume, V2-YR Ll Wl dl VP1 VR1 V1 (ft) (ft) (ft) (ft) (ft) (ft) (ft) 613 80 4.0 4.6 140 533 673 Chamber 2 Req Volume, V100- Pipe Volume, Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to YR L2 W2 d2 VP2 VR2 I Volume, V21 Volume, V2 Drain 90% (ft') (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 2,264 80 15 4.6 62 2,183 1.0 100 2,345 20.37 BASIN CATCHMENT AREA F TIME OF CONCENTRATION Overland Flow Gutter Flow u a c men eng (ft) ope, s N Tc_s (min.) Elev I (ft) 1 Llev Z (ft) Length, LG (ft) Slope, Sp (%) Gutter (ft/sec) Tc_c (min.) Total Tc (min.) F1 15.0 1.00 6.7 2531.7 2529.3 329 0.72 1.72 3.2 9.9 CONVEYANCE Sub -Catchment C Area, A (acres) i2 (in/hr) i2s (in/hr) iloo (in/hr) Q2 (cfs) Q25 (cfs) Q100 (cfs) F1 0.50 0.87 0.69 1.85 2.58 0.30 0.80 1.12 Total 0.87 0.30 0.80 1.12 SAND & GREASE TRAP No. of S&G Baffle Throat Velocity, Velocity Vault Size Traps Spacing Throat Width Throat Area Flow Rate, Q, V Flow Rate Check Check (galon) (inch) (inch) (ft) (cfs) (fps) Q2s < 3.33 cfs V < 0.5 fps 1000 1 20 48 6.67 0.80 0.12 TRUE TRUE STORAGE VOLUMES Chamber 1 Req'd Volume, Rock Void Volume, Storage Volume, V2_YR L1 W1 d1 Pipe Volume, VP1 VR1 V1 (ft) (ft) (ft) (ft) (ft) (ft) (ft) 407 125 3 5 219 662 881 Chamber 2 Req Volume, V100_ Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to YR L2 W2 d2 Pipe Volume, VP2 VR2 I Volume, V21 Volume, V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft) (in/hr) (ft) (ft) (hrs) 1,503 125 6 5 97 1,461 1.0 63 1,621 21.65 BASIN CATCHMENT AREA G TIME OF CONCENTRATION Overland Flow Gutter Flow Sub -Catchment engt (ft) ope, s M Tc_s (min.) ev (ft) Elev 2 (ft) Length, Lc (ft) ope, p M utter (ft/sec) Tc_G (min.) Total Tc (min.) G1 75.0 1.00 24.4 2533.2 554 0.80 1.81 5.1 29.5 G2 84.0 1.00 26.7 2531.4 370 0.68 1.68 3.7 30.4 CONVEYANCE Sub -Catchment C Area, A (acres) 12 (in/hr) i25 (in/hr) i100 (in/hr) Q2 (cfs) Q25 (cfs) Q100 (cfs) G1 0.50 2.24 0.41 1.09 1.52 0.46 1.22 1.70 G2 0.50 1.31 0.4 1.07 1.49 0.26 0.70 0.97 Total 3.54 0.72 1.92 2.67 SAND & GREASE TRAP No. of S&G Baffle Throat Velocity, Velocity Vault Size Traps Spacing Throat Width Throat Area Flow Rate, Q25 V Flow Rate Check Check (galon) (inch) (inch) (ft) (cfs) (fps) Q25 < 3.33 cfs V < 0.5 fps 1 20 48 6.67 1.92 0.29 TRUE TRUE STORAGE VOLUMES Chamber 1 Req'd Volume, Pipe Volume, Rock Void Volume, Storage Volume, V2-YR Ll Wl dl VP1 VR1 Vl (ft) (ft) (ft) (ft) (ft) (ft) (ft) 1,658 136 8.0 3.8 238 1,558 1,797 Chamber 2 Req Volume, V100- Pipe Volume, Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to YR L2 W2 d2 VP2 VR2 I Volume, V2i Volume, V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft) (in/hr) (ft) (ft) (hrs) 6,121 136 29 3.8 106 5,952 1.0 329 6,387 16.76 SECTION 5 Intensity -Duration -Frequency Curve ACHD Intensity -Duration -Frequency Intensity (inches per hour) Design Storm 2 5 10 25 50 100 Tc(hr) Td min) 0.17 10 0.69 1.15 1.48 1.85 2.20 2.58 0.25 15 0.59 0.97 1.22 1.56 1.86 2.18 0.33 20 0.49 0.81 1.01 1.30 1.54 1.81 0.42 25 0.43 0.71 0.89 1.14 1 1.35 1.58 0.50 30 0.41 0.67 0.85 1.08 1.29 1.51 0.58 35 0.34 0.56 0.70 0.90 1.07 1.25 0.67 40 0.31 0.51 0.64 0.82 0.98 1.15 0.75 45 0.29 0.48 0.60 0.77 0.91 1.07 0.83 50 0.27 0.45 0.56 0.72 0.85 1.00 0.92 55 0.26 0.43 0.54 0.69 0.82 0.96 1 60 0.26 0.43 0.54 0.69 0.82 0.96 2 120 0.16 0.25 0.31 0.39 0.46 0.54 3 180 0.13 0.19 0.23 0.29 0.34 0.40 6 360 0.09 0.12 0.14 0.18 0.21 0.25 12 720 0.06 0.08 0.10 0.12 0.14 0.16 24 1440 1 0.04 1 0.06 1 0.06 0.08 0.09 0.10 Intensity Duration Frequency 3 ------ 2 -)K- 5 -x- 10 2.5 - 25 t 50 2 ❑ 100 L t .5 r x X \X c 1 x \X�X X\X�X\X�X� �X-X-x 0.5- _ _ x-x-x �X-x-X ''�-------- 0 10 15 20 25 30 35 40 45 50 55 60 120 180 360 720 1440 Duration (minutes) SECTION 6 Pipe Flow Calculations Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB Al to MH Al - 25-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 0.26 Elev (ft) 102.00 v 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 10 2022 Highlighted Depth (ft) = 0.19 Q (cfs) = 0.260 Area (sqft) = 0.10 Velocity (ft/s) = 2.48 Wetted Perim (ft) = 0.90 Crit Depth, Yc (ft) = 0.21 Top Width (ft) = 0.79 EGL (ft) = 0.29 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB B2 to CB B1 - 25-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 0.77 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 10 2022 Highlighted Depth (ft) = 0.33 Q (cfs) = 0.770 Area (sqft) = 0.23 Velocity (ft/s) = 3.40 Wetted Perim (ft) = 1.22 Crit Depth, Yc (ft) = 0.37 Top Width (ft) = 0.94 EGL (ft) = 0.51 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB B1 to MH B2 - 25-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 1.80 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 2.07 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 10 2022 Highlighted Depth (ft) = 0.40 Q (cfs) = 2.070 Area (sqft) = 0.29 Velocity (ft/s) = 7.05 Wetted Perim (ft) = 1.37 Crit Depth, Yc (ft) = 0.62 Top Width (ft) = 0.98 EGL (ft) = 1.17 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB C2 to CB C1 - 25-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 0.55 Elev (ft) 102.00 v 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 10 2022 Highlighted Depth (ft) = 0.28 Q (cfs) = 0.550 Area (sqft) = 0.18 Velocity (ft/s) = 3.02 Wetted Perim (ft) = 1.12 Crit Depth, Yc (ft) = 0.31 Top Width (ft) = 0.90 EGL (ft) = 0.42 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB C1 to MH C2 - 25-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 1.40 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 1.14 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 10 2022 Highlighted Depth (ft) = 0.31 Q (cfs) = 1.140 Area (sqft) = 0.21 Velocity (ft/s) = 5.45 Wetted Perim (ft) = 1.18 Crit Depth, Yc (ft) = 0.45 Top Width (ft) = 0.93 EGL (ft) = 0.77 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB D2 to CB D1 - 25-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 0.89 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 10 2022 Highlighted Depth (ft) = 0.36 Q (cfs) = 0.890 Area (sqft) = 0.26 Velocity (ft/s) = 3.48 Wetted Perim (ft) = 1.29 Crit Depth, Yc (ft) = 0.40 Top Width (ft) = 0.96 EGL (ft) = 0.55 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB D1 to MH D2 - 25-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 1.60 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 1.62 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 10 2022 Highlighted Depth (ft) = 0.36 Q (cfs) = 1.620 Area (sqft) = 0.26 Velocity (ft/s) = 6.33 Wetted Perim (ft) = 1.29 Crit Depth, Yc (ft) = 0.54 Top Width (ft) = 0.96 EGL (ft) = 0.98 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB E2 to CB E1 - 25-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 0.41 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 10 2022 Highlighted Depth (ft) = 0.24 Q (cfs) = 0.410 Area (sqft) = 0.15 Velocity (ft/s) = 2.82 Wetted Perim (ft) = 1.02 Crit Depth, Yc (ft) = 0.27 Top Width (ft) = 0.85 EGL (ft) = 0.36 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB E1 to MH E1 -25-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 1.70 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 0.73 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 10 2022 Highlighted Depth (ft) = 0.24 Q (cfs) = 0.730 Area (sqft) = 0.15 Velocity (ft/s) = 5.02 Wetted Perim (ft) = 1.02 Crit Depth, Yc (ft) = 0.36 Top Width (ft) = 0.85 EGL (ft) = 0.63 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB F1 to MH F1 - 25-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 1.00 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 0.80 Elev (ft) 102.00 v 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 10 2022 Highlighted Depth (ft) = 0.28 Q (cfs) = 0.800 Area (sqft) = 0.18 Velocity (ft/s) = 4.40 Wetted Perim (ft) = 1.12 Crit Depth, Yc (ft) = 0.38 Top Width (ft) = 0.90 EGL (ft) = 0.58 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB G2 to CB G1 - 25-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 0.70 Elev (ft) 102.00 v 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 10 2022 Highlighted Depth (ft) = 0.32 Q (cfs) = 0.700 Area (sqft) = 0.22 Velocity (ft/s) = 3.21 Wetted Perim (ft) = 1.20 Crit Depth, Yc (ft) = 0.35 Top Width (ft) = 0.93 EGL (ft) = 0.48 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB G1 to MH G2 - 25-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 1.92 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 10 2022 Highlighted Depth (ft) = 0.55 Q (cfs) = 1.920 Area (sqft) = 0.44 Velocity (ft/s) = 4.32 Wetted Perim (ft) = 1.67 Crit Depth, Yc (ft) = 0.59 Top Width (ft) = 0.99 EGL (ft) = 0.84 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB Al to MH Al - 100-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 0.35 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 17 2022 Highlighted Depth (ft) = 0.22 Q (cfs) = 0.350 Area (sqft) = 0.13 Velocity (ft/s) = 2.71 Wetted Perim (ft) = 0.98 Crit Depth, Yc (ft) = 0.25 Top Width (ft) = 0.83 EGL (ft) = 0.33 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB B2 to CB B1 - 100-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 1.08 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 17 2022 Highlighted Depth (ft) = 0.40 Q (cfs) = 1.080 Area (sqft) = 0.29 Velocity (ft/s) = 3.68 Wetted Perim (ft) = 1.37 Crit Depth, Yc (ft) = 0.44 Top Width (ft) = 0.98 EGL (ft) = 0.61 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB B1 to MH B2 - 100-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 1.80 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 2.89 Elev (ft) 102.00 --7 101.50 101.00 100.50 100.00 99.50 Thursday, Mar 17 2022 Highlighted Depth (ft) = 0.48 Q (cfs) = 2.890 Area (sqft) = 0.37 Velocity (ft/s) = 7.71 Wetted Perim (ft) = 1.53 Crit Depth, Yc (ft) = 0.73 Top Width (ft) = 1.00 EGL (ft) = 1.40 Section 2 Depth (ft) .00 1.50 1.00 0.50 1 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB C2 to CB C1 - 100-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 0.77 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 17 2022 Highlighted Depth (ft) = 0.33 Q (cfs) = 0.770 Area (sqft) = 0.23 Velocity (ft/s) = 3.40 Wetted Perim (ft) = 1.22 Crit Depth, Yc (ft) = 0.37 Top Width (ft) = 0.94 EGL (ft) = 0.51 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB C1 to MH C2 - 100-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 1.40 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 1.58 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 17 2022 Highlighted Depth (ft) = 0.37 Q (cfs) = 1.580 Area (sqft) = 0.27 Velocity (ft/s) = 5.96 Wetted Perim (ft) = 1.31 Crit Depth, Yc (ft) = 0.54 Top Width (ft) = 0.97 EGL (ft) = 0.92 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB D2 to CB D1 - 100-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 1.23 Elev (ft) 102.00 --7 101.50 101.00 100.50 100.00 99.50 Thursday, Mar 17 2022 Highlighted Depth (ft) = 0.43 Q (cfs) = 1.230 Area (sqft) = 0.33 Velocity (ft/s) = 3.78 Wetted Perim (ft) = 1.43 Crit Depth, Yc (ft) = 0.47 Top Width (ft) = 0.99 EGL (ft) = 0.65 Section 2 Depth (ft) .00 1.50 1.00 0.50 1 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB D1 to MH D2 - 100-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 1.60 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 2.25 Elev (ft) 102.00 --7 101.50 101.00 100.50 100.00 99.50 Thursday, Mar 17 2022 Highlighted Depth (ft) = 0.43 Q (cfs) = 2.250 Area (sqft) = 0.33 Velocity (ft/s) = 6.92 Wetted Perim (ft) = 1.43 Crit Depth, Yc (ft) = 0.65 Top Width (ft) = 0.99 EGL (ft) = 1.17 Section 2 Depth (ft) .00 1.50 1.00 0.50 1 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB E2 to CB E1 - 100-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 0.57 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 17 2022 Highlighted Depth (ft) = 0.29 Q (cfs) = 0.570 Area (sqft) = 0.19 Velocity (ft/s) = 3.00 Wetted Perim (ft) = 1.14 Crit Depth, Yc (ft) = 0.32 Top Width (ft) = 0.91 EGL (ft) = 0.43 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB E1 to MH E1 - 100-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 1.70 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 1.01 Elev (ft) 102.00 v 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 17 2022 Highlighted Depth (ft) = 0.28 Q (cfs) = 1.010 Area (sqft) = 0.18 Velocity (ft/s) = 5.55 Wetted Perim (ft) = 1.12 Crit Depth, Yc (ft) = 0.42 Top Width (ft) = 0.90 EGL (ft) = 0.76 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB F1 to MH F1 - 100-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 1.00 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 1.12 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 17 2022 Highlighted Depth (ft) = 0.34 Q (cfs) = 1.120 Area (sqft) = 0.24 Velocity (ft/s) = 4.71 Wetted Perim (ft) = 1.25 Crit Depth, Yc (ft) = 0.45 Top Width (ft) = 0.95 EGL (ft) = 0.69 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB G2 to CB G1 - 100-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 0.97 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 17 2022 Highlighted Depth (ft) = 0.38 Q (cfs) = 0.970 Area (sqft) = 0.27 Velocity (ft/s) = 3.53 Wetted Perim (ft) = 1.33 Crit Depth, Yc (ft) = 0.42 Top Width (ft) = 0.97 EGL (ft) = 0.57 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. CB G1 to MH G2 - 100-yr Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.010 Calculations Compute by: Known Q Known Q (cfs) = 2.67 101.50 101.00 100.50 100.00 99.50 1 Thursday, Mar 17 2022 Highlighted Depth (ft) = 0.69 Q (cfs) = 2.670 Area (sqft) = 0.58 Velocity (ft/s) = 4.60 Wetted Perim (ft) = 1.96 Crit Depth, Yc (ft) = 0.70 Top Width (ft) = 0.92 EGL (ft) = 1.02 Section 2 Depth (ft) .00 1.50 1.00 0.50 -0.50 3 Reach (ft) SECTION 7 Drainage Basin Map Z W f Z NOT A PART NOT A PART NOT A PART Qz00 W 0 • c m t9 a_ W i y09 O um) 04 ...... 15+� 1 .q — — — — 'o,to i I I I ---- Z 1 1 � rl I I III CB F1 Z o I' III CB B1 I I I 0.87 ac. 2I39 ac. III 1C05 ac. CB E2 III a 3 f - -_ u 03 .72 ac. I CB G2 0 W SNOW CURRANT ST — I Z in CB Al _ — — 1.31 ac. W _ W z 0.44 ac. — — — — — — — — — v1l i CB B2 CB C2 — —� — — � w sNow cuRRaNT sr 1.40ac. - nnnnnn f f 0.97 ac. I I �� I ------- u w II W II z I -------- z C13G1 2.24ac. EXISTING OAKS EXISTING OAKS NORTH z CB E1 NORTH SUBDIVISION NO. 10 0.59 ac. i EXISTING OAKS SUBDIVISION NORTH W g�RNr sR�E o� NO. 6 SUBDIVISION W PEWTER POINT ST - — W PEWTER POINT ST z NO. 10 — — � 2 w Q I CB D1 w I �1.30 ac. EXISTING OAKS NORTH N EXISTING OAKS SUBDIVISION NO. 8 NORTH SUBDIVISION NO. 10 / 0 � o - --- - - ---- -- -- - jj iG �9 9 Q N EXISTING OAKS o NORTH Z Q SUBDIVISION Ld O Z Q N0, 6 Z Q z - Q U �/� Z II V/pW w Y � Q Qa U o m W Q Ld Q , ^ w v /'y'� W 0 o Z o z / ) Z w V � � o o C O w W O z Y Q O DATE: SCALE: 03/18/22 AS SHOWN DESIGN: DRAWN: N MRZ JBS o x o JOB 4468 44168-SNSWM-PH12 N FEET 80 0 40 80 160 REF. D R w NO.: oL-LGRAPHIC SCALE 1 inch = 80 ft. NHOEET 1 of •� Z CB D2 1.60