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HomeMy WebLinkAboutWPO202200049 Calculations 2022-11-22MAPLEWOOD DEVELOPMENT STORMWATER MANAGEMENT CALCULATIONS PACKET 3COTT /R"Ct�LLJNS '12-1 Lic. No. 035791 LL� 10/24/22 Date of Calculations OCTOBER 24,2022 PREPARED BY: %= COLLINS r-NGINGERING 200 GARRETT STREET, SUITE K CHARLOTTESVILLE, VA 22902 434.293.3719 PH 434.293.2813 FX www.collins-engineering.com SCS TR-55 Calculations Soils Mapping (Source: NRCS Web Soil Survey Online Database) Soils Table (Source: NRCS Web Soil Survey Online Database) Albemarle County, Virginia (VA003) Map Peircent of Unit Map Unit Name AOI Symbol 27B Elioak loam, 2 to 0.2% 7 percent slopes 28C3 Elioak clay loam, 25.5% 7 to 15 percent slopes, severely eroded 88 Udorthents, 74.3% loamy, 2 to 25 percent slopes Totals for Area of 100.00/0 Interest Note: The Udorthents loamy soil type listed in the USDA's NRCS'database does not proide a hydrologic group type. The remaining soils in this site have a hydrologic group type B, which is commonly found throughout Albemarle County. As a result, the following computations consider the site's soils to be composed of hydrologic type B soils. Precipitation Data (Source: NCAA's National Weather Service, Hydrometerorological Design Studies Center, Atlas 14 Point Precipitation Frequency Estimates) Terrain prorf't ',fa 0 10 ORI 3�1 Oft POINT PRECIPITATION FREQUENCY (PF) ESTIMATES NTH 90% CONFIDENCE INTERVALS AND SUPPLEMENTARY INFORMATION NOAA Atlas 14, Volume 2, Version 3 IPDS-based precipitation ftequency estimates with 90% confidence intervals fin inches)l Av�e �ffence Intewal (yeam) I 797 7F --1 --- --- --- —7:�F 90 7F 3.60 7F 4.60 7F A3 7F 6.67 F 7F —1B LQs7-3,M) F��]F .2 (12�4.0) (4.11�A7) 85-BAO) J1 (&91-7.4n IL A",M)JL 9.76-9M)JL (8.�7�113) 3-_13.5) IL . . . . . . JL__tf_ __ _ ____ _ L (10_ __]L 5-_153) (M_ __ u W 0 E .2 E OD S 0 0 zi z c t 0 0 F E z g t; o m ci ci �4 cs 6 C; �i r4 �4 C5 w t; 0 0 E t: 0 . m 0 0 0 0 u 0 m u m m m u 3 0 o o o 0 0 0 0 0 0 0 0 > 0 .2 12 3: > a 3 m a a 3: a 3: 0 Ea ZW U.S. Department of Agriculture Natural Resources Conservation Service TR 55 Worksheet 3: Time of Concentration (TJ or Travel Time (TJ Project: Maplewood Development Location: Worth Crossing & Proffit Rd. Check One: Present X Developed X Check One: Tc X T, Segment ID: Sheet Flow: (Applicable to T. only) I Surface description (Table 3-1) 2 Manning's roughness coeff., n (Table 3-1 3 Flow length, L (total L < 100) (ft) 4 Two-year 24-hour rainfall, P, (in.) 5 Land slope, s (ft/ft) 6 Compute Tt = [0.007(n-L)081 / P,0 5 SOA Designed By: FGM, PE Checked By: SRC, PE Through subarea n/a FL-ENG-21A 06/04 Date: 10/24/2022 Date: 10/24/2022 DA DA I DA I DA AAP WALGREENI (Pre-Dev.) (Post-Dev.) Dense Dense Grass Grass 0.24 0.24 100 40 3.60 3.60 0.15 0.3 0.10 0.04 Shallow Concentrated Flow: 7 Surface description (paved or unpaved) Unpaved Paved 8 Flow Length, L (ft) 225 125 9 Watercourse slope, s (ft/ft) 0.015 0.048 10 Average velocity, V (Figure 3-1) (ft/s) 2.0 4.4 11 Tt = L / 3600*V 0.03 0.01 Channel Flow: 12 Cross sectional flow area, a (ft) 13 Wetted perimeter, Pw (ft) 14 Hydraulic radius, r = a/Pw (ft) 15 Channel Slope, s (ft/ft) 16 Manning's Roughness Coeff, n 17 V= [ 1.49r2/3s05 I / n 18 Flow length, L (ft) 19 Tt= L / 3600*V 20 Watershed or subarea Tor Tt (Add Tt in steps 6, 11 and 19) M U 0 Ln ko M 0.01 1 0.10 1 0.14 1 0.13 1 0.10 1 1 Notes: The approved Tc for subarea AAP was 0.04 hrs, but the shortest SCS Tc is 0.10 hrs., as shown above. The approved TC for subarea Walgreens was 8.4 minutes, or 0.14 hrs. as shown above U.S. Department of Agriculture Natural Resources Conservation Service TR 55 Worksheet 4: Graphical Peak Discharge Method Project: Maplewood Development Designed By: FGM, PE Date: 10/24/2022 Location: Worth Crossing & Proffit Rd. Checked By: SRC, PE Date: 10/24/2022 Check One: Present X Developed X 1. Data Drainage Area Description Drainage Area Description Drainage Area Description Drainage Area Description DA AAP DAWALGREENS DA 1 (Pre-Dev.) DAL (Post-Dev.) Drainage Area (Am) in mile$2 0.0010 0.0032 0.0059 0.0059 Runoff curve number CN= 91 89 62 94 Time of concentration (Tc)= 0.10 0.14 0.13 0.10 Rainfall distribution type= 11 11 11 11 Pond and swamp areas spread throughout the watershed= 0 0 I 0 I 0 I J 2. Frequency -years 1 2 10 1 2 10 1 2 10 1 2 10 3. Rainfall, P (24 hour)- inches 2.97 3.60 5.43 2.97 3.60 5.43 2.97 3.60 5.43 2.97 3.60 5.43 4. Initial Abstraction, la- inches 0.19 0.19 0.19 0.24 0.24 0.24 1.21 1.21 1.21 0.38 0.38 0.38 5. Compute la/P 0.07 0.05 0.04 0.08 0.07 0.04 0.41 0.34 0.22 0.13 0.11 0.07 6. Unit peak discharge, Qu- csmAn Out of Range Out of Range 700 800 875 Out of Range 7. Runoff, Q from Worksheet 2- inches 2.06 2.65 4.42 1.89 2.47 4.21 0.40 0.68 1.73 1.48 2.01 3.65 8. Pond and Swamp adjustment factor, Fip 1 1 1 1 1 1 1 1 1 1 1 1 9. Peak Discharge, Qp- cis ,where QP=QU Am Q Fp See SCS Routing Calculations See SCS Routings (1&2yr) and Hydrograhs (10yr) See SCS Unit Hydrographs See SCS Routing Calculations Note: The Walgreens'existing UGD system is at full capacity during storm events slightly greater than the present day 2-year event. WATERSHED SUMMARY AT POINT OF ANALYSIS #1 (USED FOR CHANNEL & FLOOD PROTECTION COMPLIANCE) Area, Time of 1-year 2-year 10-year CIN ac. Conc., hrs. Flow, cfs Flow, cis Flow, cfs DA AAP 91 0.65 0.10 DAWALGREENS 89 2.02 0.14 3.62 6.61 24.27 DA 1 (Pre-Dev) 62 3.75 0.13 74 6.42 Post -Development Area, Time of 1-year 2-year 10-year CIN ac. Conc., hrs. Flow, cfs Flow, cis Flow, cfs DA AAP 91 0.65 0.10 DAWALGREENS 89 2.02 0.14 1.46 4.56 22.92 DA 1 (Post-Dev.) 84 3.75 0.10 86 6.42 9 VAC 25-870-66 Channel & Flood Protection Analysis (At Point of Analysis #1. See supporting documents within this report for details.) 9 VAC 25-870-66 (Channel Protection at Point of Analysis #1) Section B: Channel Protection "Concentrated stormwater flow shall be released into a stormwater conveyance system and shall meet the criteria in subdivision 1, 2 or 3 of this subsection..." Section BA: Manmade stormwater conveyance systems "When stormwater from a development is discharged to a manmade stormwater conveyance system, following the land -disturbing activity, either..." a. or b. shall be met: Section B.I.b. "The peak discharge requirements for concentrated stormwater flow to natural stormwater conveyance systems in subdivision 3 of this subsection shall be met." Section B.3 "... the maximum peak flow rate from the one-year 24-hour storm following the land -disturbing activity shall be calculated either.." a. or b." Section B.3.a. In accordance with the following methodology: Q Developed _< I. F. * (Q Pre -Developed * RV Pre -Developed ) / RV Developed Q Allowed Where: Q Pre -Developed � CN Pre -Developed � S Pre -Developed � RV Pre -Developed � CN Post -Developed � S Post -Developed � RV Post -Developed � IR = Q Developed < 1.52 cfs 3.62 cfs (From Worksheet 4 Watershed Summary) 74 (From Worksheet 4 Watershed Summary) 3.57 (From SCS TR-55 eq. 2-4) 0.87 in. (From SCS TR-55 eq. 2-3) 86 (From Worksheet 4 Watershed Summary) 1.59 (From SCS TR-55 eq. 2-4) 1.66 in. (From SCS TR-55 eq. 2-3) 0.80 (Factor of Safety) 1.46 cfs Section B.4 Limits of Analysis The analysis terminates at the SWIVI facility since subsection B.3.a is met. 9 VAC 25-870-66 (Flood Protection at Point of Analysis #1) Section C: Flood Protection "Concentrated stormwater flow shall be released into a stormwater conveyance system and shall meet one of the following criteria as demonstrated by use of acceptable hydrologic and hydraulic methodologies:" Section C.2.b.: The point of discharge (the site outfall), "releases a postclevelopment peak flow rate for the 10-year 24-hour storm event that is less than the preclevelopment peak flow rate from the 10-year 24-hour storm event. Downstream stormwater conveyance systems do not require any additional analysis to show compliance with flood protection criteria if this option is utilized." Pre -Development Peak SCS 10-yr, 24-hour Flow = 24.27 cfs Post -Development Peak SCS 10-yr, 24-hour Flow = 22.92 cfs Section C.3 Limits of Analysis The flood protection analysis terminates at the site outfall since subsection C.2.b is met. SCS TR-55 Computations for Advanced Auto Parts 1. The existing Advanced Auto Parts development, upland of the proposed site, discharges runoff onto the subject property. This runoff is defined as subarea 'AAP'. 2. The runoff from subarea 'AAP' is detained in the Advanced Auto Parts property prior to being released into the subject property. Its attenuation is primarily from the two proposed storm pipes located in the southern corner of the Advanced Auto Parts property. These two outlet pipes have low -flow orifices/plates on their upstream ends, restricting the flows to the subject property. Because of this scenario, the following routing calculations were generated. These routing calculations create outflow hydrographs, that will later be synchronized in this report with other contributing hydrographs, that will then be used to evaluate the overall watershed draining to point of analysis #1. 3. In the pre -development state, the aforementioned subarea 'AAP' runoff drains to point of analysis #1 through the site via overland flow. In the post -development state, this runoff will be collected via new storm sewer and attenuated further in the proposed Underground Detention (UGD) System #1. SCS TR-55 Advanced Auto Parts Routings Advanced Auto Parts Routings BasinFlow printout INPUT: Basin: Advanced Auto Parts Routings 0 Contour Areas Elevation(ft) Area(sf) Computed Vol.(cy) 3 Storage Pipes Storage pipe 0 name: Approved Advanced Auto Parts- Total Area MHs diameter (in) 48.000 length (ft) 12.150 invert (ft) 539.100 angle 0.287 volume (cy) 5.655 Storage pipe I name: Approved Advanced Auto Parts- Total Area Line G diameter (in) 15.000 length (ft) 32.000 invert (ft) 539.100 angle 0.287 volume (cy) 1.454 Storage pipe 2 name: Approved Advanced Auto Parts- Total Area Line H diameter (in) 24.000 length (ft) 120.000 invert (ft) 539.100 angle 0.287 volume (cy) 13.963 Start—Elevation(ft) 539.10 Vol.(cy) 0.00 2 Outlet Structures Outlet structure 0 Orifice name: Approved Advanced Auto Parts Low -Flow Orifice area (sf) 0.315 diameter or depth (in) 7.600 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 539.100 multiple 1 discharge through dam Page 1 Advanced Auto Parts Routings Outlet structure I Orifice name: Approved Advanced Auto area (sf) 0.315 diameter or depth (in) 7.600 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 539.600 multiple 1 discharge through dam 3 Inflow Hydrographs Hydrograph 0 SCS name: lyr. SCS, 24-hr Design Storm Area (acres) 0.650 CN 91.000 Type 2 rainfall, P (in) 2.970 time of conc. (hrs) 0.1000 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 1.685 peak time (hrs) 11.917 volume (cy) 178.425 Hydrograph I SCS name: 2yr. SCS, 24-hr Design Storm Area (acres) 0.650 CN 91.000 Type 2 rainfall, P (in) 3.600 time of conc. (hrs) 0.1000 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 2.174 peak time (hrs) 11.917 volume (cy) 230.183 Page 2 Parts Outlet to StormFilters Hydrograph 2 SCS name: Area (acres) CN Type rainfall, P (in) time of conc. (hrs) time increment (hrs) time limit (hrs) fudge factor routed peak flow (cfs) peak time (hrs) volume (cy) OUTPUT: Advanced Auto Parts Routings 10yr. SCS, 24-hr Design Storm 0.650 91.000 2 5.430 0.1000 0.0200 30.000 1.00 true 3.629 11.917 384.237 Routing Method: storage -indication Hydrograph 0 Routing Summary of Peaks: lyr. SCS, 24-hr Design Storm inflow (cfs) 1.677 at 11.92 (hrs) discharge (cfs) 1.570 at 11.94 (hrs) water level (ft) 540.080 at 11.94 (hrs) storage (cy) 6.370 Hydrograph I Routing Summary of Peaks: 2yr. SCS, 24-hr Design Storm inflow (cfs) 2.164 at 11.92 (hrs) discharge (cfs) 2.002 at 11.96 (hrs) water level (ft) 540.319 at 11.96 (hrs) storage (cy) 9.058 Hydrograph 2 Routing Summary of Peaks: 10yr. SCS, 24-hr Design Storm inflow (cfs) 3.612 at 11.92 (hrs) discharge (cfs) 3.298 at 11.96 (hrs) water level (ft) 541.379 at 11.96 (hrs) storage (cy) 18.369 Wed Oct 19 12:41:05 EDT 2022 Page 3 SCS TR-55 Advanced Auto Parts Outflow Hydrographs These hydrographs will be synchronized with other hydrographs later in this report for a full evaluation of the entire watershed draining to point of analysis #1. Advanced Auto Pads (Subarea AAP) Outflow Hydrograph From Routing Calculations Time (hrs) Outflow (cfs) 0.0 0.00 0.5 0.02 1.0 0.02 1.5 0.02 2.0 0.02 2.5 0.02 3.0 0.02 3.5 0.03 4.0 0.03 4.5 0.03 5.0 0.03 5.5 0.03 6.0 0.03 6.5 0.03 7.0 0.04 7.5 0.04 8.0 0.04 8.5 0.05 9.0 0.06 9.5 0.06 10.0 0.07 10.5 0.08 11.0 0.11 11.5 0.18 11.9 1.46 12.0 1.57 12.1 0.70 12.2 0.30 12.3 0.23 12.4 0.20 12.5 0.17 13.0 0.11 13.5 0.08 14.0 0.07 14.5 0.06 15.0 0.05 15.5 0.05 16.0 0.04 16.5 0.04 17.0 0.04 17.5 0.04 18.0 0.03 18.5 0.03 19.0 0.03 19.5 0.03 20.0 0.03 20.5 0.02 21.0 0.02 21.5 0.02 22.0 0.02 22.5 0.02 23.0 0.02 23.5 0.02 24.0 0.02 24.5 0.00 25.0 0.00 25.5 0.00 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30.5 0.00 31.0 0.00 CM -020 0 Outflow Hydrograph (1-yr Design Storm) 1.80 1.60 - 11.00 - -11 .40 - 1.20 0.80 0.0 0.40 0.20 a 5.0 .0 I -A 20.0 25.0 300 -0 Advanced Auto Pads (Subarea AAP) Outflow Hydrograph From Routing Calculations Time (hrs) Outflow (cfs) 0.0 0.00 0.5 0.03 1.0 0.03 1.5 0.03 2.0 0.03 2.5 0.03 3.0 0.03 3.5 0.03 4.0 0.03 4.5 0.04 5.0 0.04 5.5 0.04 6.0 0.04 6.5 0.04 7.0 0.05 7.5 0.05 8.0 0.05 8.5 0.06 9.0 0.07 9.5 0.07 10.0 0.08 10.5 0.11 11.0 0.14 11.5 0.22 11.9 1.81 12.0 2.00 12.1 0.94 12.2 0.40 12.3 0.29 12.4 0.25 12.5 0.21 13.0 0.14 13.5 0.11 14.0 0.08 14.5 0.08 15.0 0.07 15.5 0.06 16.0 0.05 16.5 0.05 17.0 0.05 17.5 0.05 18.0 0.04 18.5 0.04 19.0 0.04 19.5 0.03 20.0 0.03 20.5 0.03 21.0 0.03 21.5 0.03 22.0 0.03 22.5 0.03 23.0 0.03 23.5 0.03 24.0 0.03 24.5 0.00 25.0 0.00 25.5 0.00 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30.5 0.00 31.0 0.00 2.50 2.00 1.50 1.00 0.50 0.00 _0 50 Outflow Hydrograph (2-yr Design Storm) Advanced Auto Pads (Subarea AAP) Outflow Hydrograph From Routing Calculations Time (hrs) Outflow cfs) 0.0 0.00 0.5 0.04 1.0 0.04 1.5 0.04 2.0 0.05 2.5 0.05 3.0 0.05 3.5 0.05 4.0 0.05 4.5 0.06 5.0 0.06 5.5 0.06 6.0 0.07 6.5 0.07 7.0 0.07 7.5 0.08 8.0 0.08 8.5 0.09 9.0 0.11 9.5 0.11 10.0 0.13 10.5 0.17 11.0 0.23 11.5 0.35 11.9 2.86 12.0 3.30 12.1 1.86 12.2 0.65 12.3 0.48 12.4 0.39 12.5 0.33 13.0 0.22 13.5 0.17 14.0 0.13 14.5 0.12 15.0 0.11 15.5 0.10 16.0 0.08 16.5 0.08 17.0 0.08 17.5 0.07 18.0 0.07 18.5 0.06 19.0 0.06 19.5 0.05 20.0 0.05 20.5 0.05 21.0 0.05 21.5 0.05 22.0 0.05 22.5 0.04 23.0 0.04 23.5 0.04 24.0 0.04 24.5 0.00 25.0 0.00 25.5 0.00 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30.5 0.00 31.0 0.00 4M 3 50 100 2.50 2.00 1.50 1.00 0.50 CM 0 -050 Outflow Hydrograph (10-yr Design Storm) SCS TR-55 Computations for Walgreens 1. The existing Walgreens development, upland of the proposed site, discharges runoff onto the subject property. This runoff is defined as subarea Valgreens'. 2. The runoff from subarea Valgreens' is detained in the Walgreens property prior to being released into the subject property. Its attenuation is primarily from an existing 48" HIDPE UGID system. Because of this scenario, the following routing calculations were generated. These routing calculations create outflow hydrographs, that will be synchronized with other hydrographs later in this report so that the full watershed draining to point of analysis #1 can be analyzed. 3. In the pre -development state, subarea Valgreens' drains to the point of analysis #1 via overland flow. In the post -development state subarea Valgreens' will be collected in new storm sewer and routed into the proposed UGID System #1 for further attenuation, before ultimately being released back into point of analysis #1. SCS TR-55 Walgreens Routings BasinFlow printout INPUT: Basin: Walgreens Routings 0 Contour Areas Elevation(ft) Area(sf) 4 Storage Pipes Storage pipe 0 Walgreens Routings Computed Vol.(cy) name: Approved Walgreens 48" HDPE UGD System- A-D diameter (in) 48.000 length (ft) 115.000 invert (ft) 535.100 angle 0.287 volume (cy) 53.523 Storage pipe I name: Approved Walgreens 48" HDPE UGD System- B-E diameter (in) 48.000 length (ft) 115.000 invert (ft) 535.300 angle 0.287 volume (cy) 53.523 Storage pipe 2 name: Approved Walgreens 48" HDPE UGD System- C-F diameter (in) 48.000 length (ft) 115.000 invert (ft) 535.400 angle 0.287 volume (cy) 53.523 Storage pipe 3 name: Approved Walgreens 48" HDPE UGD System- Connection Pipes diameter (in) 48.000 length (ft) 34.000 invert (ft) 535.100 angle 0.287 volume (cy) 15.824 Start—Elevation(ft) 535.10 Vol.(cy) 0.00 Page 1 4 Outlet Structures Outlet structure 0 Orifice Walgreens Routings name: Approved Walgreens Line B Pipe area (sf) 3.142 diameter or depth (in) 24.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 535.000 multiple 1 discharge out of riser Outlet structure I Orifice name: Approved Walgreens Low -Flow Orifice area (sf) 0.260 diameter or depth (in) 6.900 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 535.100 multiple 1 discharge into riser Outlet structure 2 Weir name: Approved Walgreens IB-20 diameter (in) 72.000 side angle 0.000 coefficient 3.300 invert (ft) 542.400 multiple 1 discharge into riser transition at (ft) 1.823 orifice coef. 0.500 orifice area (sf) 28.274 Outlet structure 3 Weir name: Approved Walgreens Overflow length (ft) 6.000 side angle 90.000 coefficient 3.000 invert (ft) 540.400 multiple I discharge out of riser transition at (ft) 0.000 orifice coef. 0.500 orifice area (sf) 0.000 Page 2 Walgreens Routings 3 Inflow Hydrographs Hydrograph 0 SCS name: lyr. SCS, 24-hr Design Storm Area (acres) 2.020 CN 89.000 Type 2 rainfall, P (in) 2.970 time of conc. (hrs) 0.1400 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 4.494 peak time (hrs) 11.935 volume (cy) 508.095 Hydrograph I SCS name: 2yr. SCS, 24-hr Design Storm Area (acres) 2.020 CN 89.000 Type 2 rainfall, P (in) 3.600 time of conc. (hrs) 0.1400 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 5.878 peak time (hrs) 11.935 volume (cy) 664.668 Hydrograph 2 SCS name: Full UGD System Capacity Area (acres) 2.020 CN 89.000 Type 2 rainfall, P (in) 3.820 time of conc. (hrs) 0.1400 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 6.370 peak time (hrs) 11.935 volume (cy) 720.234 Page 3 Walgreens Routings OUTPUT: Routing Method: storage -indication Hydrograph 0 Routing Summary of inflow (cfs) discharge (cfs) water level (ft) storage (cy) Hydrograph I Routing Summary of inflow (cfs) discharge (cfs) water level (ft) storage (cy) Hydrograph 2 Routing Summary of inflow (cfs) discharge (cfs) water level (ft) storage (cy) Peaks: lyr. SCS, 4.474 at 1.666 at 537.947 at 111.732 Peaks: 2yr. SCS, 5.853 at 1.963 at 538.939 at 159.755 24-hr Design Storm 11.94 (hrs) 12.10 (hrs) 12.12 (hrs) 24-hr Design Storm 11.94 (hrs) 12.12 (hrs) 12.12 (hrs) Peaks: Full UGD System Capacity 6.342 at 11.94 (hrs) 2.180 at 12.12 (hrs) 539.767 at 12.12 (hrs) 176.192 Thu Oct 20 15:52:10 EDT 2022 Page 4 SCS TR-55 Walgreens Outflow Hydrographs Notes: 1. These hydrographs will be synchronized with other hydrographs later in this report for the full evaluation of the entire watershed draining to point of analysis #1. 2. The existing Walgreens UGD system reaches full capacity in storm events slightly greater than the present day 2-year storm event. Due to this circumstance, multiple 10-year hydrographs were created. A hydrograph was created for the facility's full capacity, which was then subtracted from the facility's 10-year inflow hydrograph. The resultant 10-year hydrograph represents the flow into the subject property, which considers the partial attenuation in the facility and the facility's overflow. Walgreens (Subarea Walgreens) Outflow Hydrograph From Routing Calculations Time (hrs) Outflow (cts) 0.0 0.00 0.5 0.07 1.0 0.08 1.5 0.08 2.0 0.08 2.5 0.08 3.0 0.09 3.5 0.09 4.0 0.09 4.5 0.10 5.0 0.11 5.5 0.11 6.0 0.12 6.5 0.12 7.0 0.13 7.5 0.14 8.0 0.15 8.5 0.17 9.0 0.20 9.5 0.21 10.0 0.24 10.5 0.30 11.0 0.39 11.5 0.51 11.9 1.28 12.0 1.46 12.1 1.67 12.2 1.63 12.3 1.56 12.4 1.48 12.5 1.39 13.0 0.84 13.5 0.32 14.0 0.25 14.5 0.22 15.0 0.20 15.5 0.18 16.0 0.16 16.5 0.15 17.0 0.14 17.5 0.13 18.0 0.12 18.5 0.11 19.0 0.11 19.5 0.10 20.0 0.09 20.5 0.09 21.0 0.08 21.5 0.08 22.0 0.08 22.5 0.08 23.0 0.08 23.5 0.08 24.0 0.07 24.5 0.00 25.0 0.00 25.5 0.00 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30.5 0.00 31.0 0.00 Outflow Hydrograph (1-yr Design Storm) 1.80 1 1.60 1.40 1.20 Lon 0.80 0.0 0.40 0.20 coo -020 00 510 ui.0 I�A 2q.0 25. 30.0 a .0 Walgreens (Subarea Walgreers) Outflow Hydrograph From Routing �Iculations Tinto (hrs) Outflow (Cfs) 0.0 0.00 0.5 0.09 1.0 0.10 1.5 0.10 2.0 0.11 2.5 0.11 3.0 0.11 3.5 0.12 4.0 0.12 4.5 0.13 S.0 0.14 S.5 0.14 6.0 0.15 6.5 0.16 7.0 0.17 7.5 0.18 8.0 0.19 8.5 0.22 9.0 0.25 9.5 0.27 10.0 0.31 10.5 0.38 11.0 OAS 11.5 0.60 11.9 1AS 12.0 1.67 12.1 1.96 12.2 1.93 12.3 1.85 12.4 1.76 12.5 1.67 13.0 1.20 13.5 0.56 14.0 0.32 14.5 0.28 15.0 0.26 15.5 0.23 16.0 0.20 16.5 0.19 17.0 0.18 17.5 0.17 18.0 0.16 18.5 0.15 19.0 0.14 19.5 0.13 20.0 0.12 20.5 0.11 21.0 0.11 21.5 0.11 22.0 0.11 22.5 0.10 23.0 0.10 23.5 0.10 24.0 0.10 24.5 0.00 2S.0 0.00 2S.5 0.00 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30S 0.00 31.0 0.00 250 2M ISO IM 0so OM Aso Outflow Hydrogmph (2-yr Design Storm) Worksheet 5b (Modified for Clarity): Basic watershed Data 10-yr. 24-hr. SCS TR-55 Method Unit Hydrograph forthe la/P & Tc Listed Below Subarea Tc (hrs.) Tt (hr.) la / P Am*Q (Mi2 -in) DAWALGREENS 0.14 0.14 0.04 0.0133 Hydrograph Time 10-yr Discharges (hrs.) (cfs) 0.0 0.00 11.0 0.32 11.3 0.45 11.6 0.70 11.9 4.44 12.0 8.59 12.1 13.41 12.2 8.27 12.3 2.88 12.4 1.95 12.5 1.63 12.6 1.38 12.7 1.14 12.8 1.01 13.0 0.88 13.2 0.76 13.4 0.68 13.6 0.61 13.8 0.56 14.0 0.50 14.3 0.45 14.6 0.42 15.0 0.39 15.5 0.35 16.0 0.31 16.5 0.28 17.0 0.27 17.5 0.25 18.0 0.24 19.0 0.20 20.0 0.17 22.0 0.16 26.0 0.00 16.00 14.00 12.00 MOO 8.00 6.00 4.00 2.00 0.00 0 SCS TR-55 Inflow Hydrograph, Subarea 'Walgreens' (Without Accounting for Attenuation in Existing Facility) Walgreens (Subarea Walgreens) Time Outno. (cls) Hydrograph (hrs) From Routing Calculations 0.0 0.00 0.5 0.10 1.0 0.11 1.5 0.11 2.0 0.11 2.5 0.12 3.0 0.12 3.5 0.13 4.0 0.13 4.5 0.14 5.0 0.15 5.5 0.16 6.0 0.17 6.5 0.17 7.0 0.18 7.5 0.19 8.0 0.20 8.5 0.23 9.0 0.27 9.5 0.28 10.0 0.33 10.5 0.40 11.0 0.48 11.5 0.63 11.9 1.51 12.0 1.74 12.1 2.18 12.2 2.05 12.3 1.95 12.4 1.85 12.5 1.76 13.0 1.29 13.5 0.70 14.0 0.35 14.5 0.30 15.0 0.28 15.5 0.25 16.0 0.22 16.5 0.20 17.0 0.19 17.5 0.18 18.0 0.17 18.5 0.16 19.0 0.15 19.5 0.14 20.0 0.13 20.5 0.12 21.0 0.12 21.5 0.12 22.0 0.11 22.5 0.11 23.0 0.11 23.5 0.11 24.0 0.10 24.5 0.00 25.0 0.00 25.5 0.00 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30.5 0.00 31.0 0.00 2.50 2.00 1.50 1.00 0.50 0.00 -0.50 Facility's Full Capacity Outflow Hydrograph (Less Severe than the 10-yr Design Storm) Final Outflow Hydrograph From Walgreens'Int, the Subject Site (Takes into account partial attenuation in the existing UGD system). 10-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc Listed Below Subarea DA WALGREENS Hydrograph Time 10-yr Discharge� (hrs.) (ch) 0.0 0.00 0.5 0.06 1.0 0.06 1.5 0.06 2.0 0.07 2.5 0.07 3.0 0.07 3.5 0.07 4.0 0.08 4.5 0.08 5.0 0.09 5.5 0.09 6.0 0.10 6.5 0.10 7.0 0.11 7.5 0.11 8.0 0.12 8.5 0.14 9.0 0.17 9.5 0.17 10.0 0.21 10.5 0.27 11.0 0.32 11.3 0.45 11.6 0.70 11.9 4.44 12.0 4.80 12.1 12.90 12.2 8.27 12.3 2.88 12.4 1.95 12.5 1.63 12.6 1.38 12.7 1.14 12.8 1.01 13.0 0.88 13.2 0.76 13.4 0.68 13.6 0.61 13.8 0.56 14.0 0.50 14.3 0.45 14.6 0.42 15.0 0.39 15.5 0.35 16.0 0.31 16.5 0.28 17.0 0.27 17.5 0.25 18.0 0.24 19.0 0.20 20.0 0.17 22.0 0.16 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30.5 0.00 31.0 0.00 12uD MOD 8AD 6AD 4AD 2.00 000 SCSTR-55 Final Outflow Hydrograph from 'Walgreens' Into the Subject Site [Fu I I UGD System Capacity subtracted from Inflow) 5.0 10.0 15.0 20.0 25.0 30.0 35.0 SCS TR-55 Pre -Development DA 1 Inflow Hydrographs Worksheet 5b (Modified for Clarity): Basic watershed Data I-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc Listed Below Subarea Tc (hrs.) Tt (hr.) la/P Am*Q (Mi2 -in) DA I (Pre-Dev.) 0.13 0.13 0.41 0.0023 Hydrograph Time I-yr Discharges (hrs.) (cfs) 0.0 0.00 11.0 0.00 11.3 0.00 11.6 0.00 11.9 0.00 12.0 0.16 12.1 1.25 12.2 0.88 12.3 0.46 12.4 0.40 12.5 0.36 12.6 0.31 12.7 0.27 12.8 0.25 13.0 0.23 13.2 0.21 13.4 0.19 13.6 0.18 13.8 0.17 14.0 0.16 14.3 0.14 14.6 0.14 15.0 0.13 15.5 0.12 16.0 0.11 16.5 0.10 17.0 0.10 17.5 0.09 18.0 0.09 19.0 0.08 20.0 0.07 22.0 0.07 26.0 0.00 1.40 1.20 1.00 0.80 0.60 0.40 0.20 000 0.0 SCS TR-55 Pre -Development Unit Hydrograph (DA 1) 5.0 10.0 15.0 20.0 25.0 30.0 Worksheet 5b (Modified for Clarity): Basic watershed Data 2-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc Listed Below Subarea Tc (hrs.) Tt (hr.) la/P Am*Q (Mi2 -in) DA I (Pre-Dev.) 0.13 0.13 0.34 0.0040 Hydrograph Time 2-yr Discharges (hrs.) (cfs) 0.0 0.00 11.0 0.00 11.3 0.00 11.6 0.00 11.9 0.61 12.0 2.25 12.1 3.71 12.2 2.08 12.3 0.86 12.4 0.68 12.5 0.59 12.6 0.50 12.7 0.42 12.8 0.38 13.0 0.35 13.2 0.30 13.4 0.27 13.6 0.25 13.8 0.23 14.0 0.21 14.3 0.19 14.6 0.17 15.0 0.17 15.5 0.15 16.0 0.13 16.5 0.12 17.0 0.12 17.5 0.11 18.0 0.11 19.0 0.10 20.0 0.08 22.0 0.08 26.0 0.00 4.00 3.50 3.00 2.50 2.00 1.50 1.00 0.50 0.00 SCS TR-55 Pre -Development Unit Hydrograph (DA 1) 5.0 10.0 15.0 20.0 25.0 30.0 Worksheet 5b (Modified for Clarity): Basic watershed Data 10-yr. 24-hr. SCS TR-55 Method Unit Hydrograph forthe la/P & Tc Listed Below Subarea Tc (hrs.) Tt (hr.) la/P Am*Q (Mi2 -in) DA I (Pre-Dev.) 0.13 0.13 0.22 0.0102 Hydrograph Time 10-yr Discharges (hrs.) (cfs) 0.0 0.00 11.0 0.00 11.3 0.00 11.6 0.00 11.9 1.57 12.0 5.77 12.1 9.52 12.2 5.33 12.3 2.21 12.4 1.75 12.5 1.51 12.6 1.28 12.7 1.09 12.8 0.99 13.0 0.90 13.2 0.77 13.4 0.70 13.6 0.64 13.8 0.59 14.0 0.54 14.3 0.49 14.6 0.44 15.0 0.43 15.5 0.39 16.0 0.35 16.5 0.32 17.0 0.30 17.5 0.28 18.0 0.27 19.0 0.24 20.0 0.20 22.0 0.19 26.0 0.00 10.00 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 SCS TR-55 Pre -Development Unit Hydrograph (DA 1) SCS TR-55 Post -Development DA 1 Inflow Hydrographs Worksheet 5b (Modified for Clarity): Basic watershed Data I-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc Listed Below Subarea Tc (hrs.) Tt (hr.) la/P Am*Q (Mi2 -in) DA I (Post-Dev.) 0.10 0.10 0.13 0.0087 Hydrograph Time I-yr Discharges (hrs.) (cfs) 0.0 0.00 11.0 0.21 11.3 0.30 11.6 0.46 11.9 2.90 12.0 5.62 12.1 8.78 12.2 5.41 12.3 1.89 12.4 1.28 12.5 1.07 12.6 0.90 12.7 0.75 12.8 0.66 13.0 0.57 13.2 0.50 13.4 0.44 13.6 0.40 13.8 0.37 14.0 0.33 14.3 0.30 14.6 0.28 15.0 0.25 15.5 0.23 16.0 0.20 16.5 0.18 17.0 0.17 17.5 0.17 18.0 0.16 19.0 0.13 20.0 0.11 22.0 0.10 26.0 0.00 10.00 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 SCS TR-55 Post- Development Unit Hydrograph (DA 1) Worksheet 5b (Modified for Clarity): Basic watershed Data 2-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc Listed Below Subarea Tc (hrs.) Tt (hr.) la/P Am*Q (Mi2 -in) DA I (Post-Dev.) 0.10 0.10 0.11 0.0118 Hydrograph Time 2-yr Discharges (hrs.) (cfs) 0.0 0.00 11.0 0.28 11.3 0.40 11.6 0.63 11.9 3.94 12.0 7.63 12.1 11.91 12.2 7.35 12.3 2.56 12.4 1.73 12.5 1.45 12.6 1.23 12.7 1.01 12.8 0.90 13.0 0.78 13.2 0.67 13.4 0.60 13.6 0.54 13.8 0.50 14.0 0.45 14.3 0.40 14.6 0.38 15.0 0.34 15.5 0.31 16.0 0.27 16.5 0.25 17.0 0.24 17.5 0.22 18.0 0.21 19.0 0.18 20.0 0.15 22.0 0.14 26.0 0.00 SCS TR-55 Post- Development Unit Hydrograph (DA 1) Worksheet 5b (Modified for Clarity): Basic watershed Data 10-yr. 24-hr. SCS TR-55 Method Unit Hydrograph forthe la/P & Tc Listed Below Subarea Tc (hrs.) Tt (hr.) la/P Am*Q (Mi2 -in) DA I (Post-Dev.) 0.10 0.10 0.07 0.0214 Hydrograph Time 10-yr Discharges (hrs.) (cfs) 0.0 0.00 11.0 0.51 11.3 0.73 11.6 1.13 11.9 7.15 12.0 13.85 12.1 21.62 12.2 13.34 12.3 4.65 12.4 3.15 12.5 2.63 12.6 2.23 12.7 1.84 12.8 1.63 13.0 1.41 13.2 1.22 13.4 1.09 13.6 0.98 13.8 0.90 14.0 0.81 14.3 0.73 14.6 0.69 15.0 0.62 15.5 0.56 16.0 0.49 16.5 0.45 17.0 0.43 17.5 0.41 18.0 0.39 19.0 0.32 20.0 0.28 22.0 0.26 26.0 0.00 25.00 SCS TR-55 Post -Development Unit Hydrograph (DA 1) Synchronized Pre -Development Hydrographs The following synchronized pre -development hydrographs reflect the runoff exiting the subject property at point of analysis #1. These hydrographs synchronize the Advanced Auto Parts hydrographs, the Walgreens hydrographs and the DA 1 pre -development hydrographs. The peak flows from these synchronized hydrographs were used in the channel and flood protection computations. Overall Synchronized Pre -Development Hydrograph, Combines the Walgreens & Advanced Auto Parts Outflow Hydrographs with the DA I Pre-Dev. Inflow Hydrograph (Takes into account allenuation in the existing UGD systems at Advanced Auto Parts and Walgreens). 1-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc, Listed Below Hydrograph Time I-yr Discharges (hrs.) (cfs) 0.0 0.00 0.5 0.09 1.0 0.10 1.5 0.10 2.0 0.10 2.5 0.11 3.0 0.11 3.5 0.12 4.0 0.12 4.5 0.13 5.0 0.14 5.5 0.14 6.0 0.15 6.5 0.16 7.0 0.17 7.5 0.18 8.0 0.18 8.5 0.22 9.0 0.25 9.5 0.26 10.0 0.31 10.5 0.39 11.0 0.50 11.3 0.59 11.6 0.90 11.9 2.75 12.0 3.20 12.1 3.62 12.2 2.81 12.3 2.25 12.4 2.07 12.5 1.91 12.6 1.75 12.7 1.59 12.8 1.46 13.0 1.17 13.2 0.83 13.4 0.64 13.6 0.56 13.8 0.51 14.0 0.47 14.3 0.43 14.6 0.41 15.0 0.38 15.5 0.34 16.0 0.31 16.5 0.29 17.0 0.27 17.5 0.26 18.0 0.24 19.0 0.21 20.0 0.19 22.0 0.17 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30.5 0.00 31.0 0.00 4.0D 3.50 3.0D 2.50 2.00 1.50 1.00 0.50 0.0D 0.0 SCS TR-55 Overall Synchronized Pre -Development Hydrograph (From Walgreers, Advanced Auto Parts & Pre -Development DA 1) 5.0 10.0 15.0 20.0 25.0 30.0 35.0 Overall Synchronized Pre -Development Hydrograph, Combines the Walgreens & Advanced Auto Parts Outflow Hydrographs with the DA I Pre-Dev. Inflow Hydrograph (Takes into account allenuation in the existing UGD systems at Advanced Auto Parts and Walgreens). 2-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc, Listed Below Hydrograph Time 2-yr Discharges (hrs.) WS) 0.0 0.00 0.5 0.12 1.0 0.12 1.5 0.13 2.0 0.13 2.5 0.14 3.0 0.15 3.5 0.15 4.0 0.15 4.5 0.17 5.0 0.18 5.5 0.18 6.0 0.20 6.5 0.20 7.0 0.22 7.5 0.23 8.0 0.24 8.5 0.28 9.0 0.32 9.5 0.34 10.0 0.39 10.5 0.48 11.0 0.59 11.3 0.72 11.6 1.05 11.9 3.88 12.0 5.94 12.1 6.61 12.2 4.41 12.3 3.00 12.4 2.69 12.5 2.47 12.6 2.26 12.7 2.08 12.8 1.93 13.0 1.68 13.2 1.40 13.4 1.09 13.6 0.79 13.8 0.68 14.0 0.62 14.3 0.56 14.6 0.52 15.0 0.49 15.5 0.44 16.0 0.39 16.5 0.36 17.0 0.35 17.5 0.32 18.0 0.31 19.0 0.27 20.0 0.23 22.0 0.21 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30.5 0.00 31.0 0.00 7.0D 6.0D Son 4.0D 3.0D 2.0D 1.0D 0.0D 0.0 SCS TR-55 Overall Synchronized Pre -Development Hydrograph (From Walgreers, Advanced Auto Parts & Pre -Development DA 1) 5.0 10.0 15.0 20.0 25.0 30.0 35.0 Overall Synchronized Pre -Development Hydrograph, Combines the Walgreens & Advanced Auto Parts Outflow Hydrographs with the DA I Pre-Dev. Inflow Hydrograph (Takes into account allenuation in the existing UGD systems at Advanced Auto Parts and Walgreens). 10-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc Listed Below Hydrograph Time 10-yr Discharges (hrs.) (cfs) 0.0 0.00 0.5 0.10 1.0 0.10 1.5 0.10 2.0 0.11 2.5 0.11 3.0 0.12 3.5 0.12 4.0 0.13 4.5 0.14 5.0 0.15 5.5 0.15 6.0 0.16 6.5 0.17 7.0 0.18 7.5 0.19 8.0 0.20 8.5 0.23 9.0 0.28 9.5 0.29 10.0 0.34 10.5 0.44 11.0 0.54 11.3 0.75 11.6 1.24 11.9 8.86 12.0 14.18 12.1 24.27 12.2 14.25 12.3 5.57 12.4 4.09 12.5 3.48 12.6 2.95 12.7 2.49 12.8 2.24 13.0 2.00 13.2 1.72 13.4 1.56 13.6 1.41 13.8 1.29 14.0 1.18 14.3 1.06 14.6 0.98 15.0 0.92 15.5 0.83 16.0 0.74 16.5 0.67 17.0 0.65 17.5 0.61 18.0 0.58 19.0 0.50 20.0 0.43 22.0 0.40 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30.5 0.00 31.0 0.00 30.00 25.00 20.00 15.00 10.00 5.W 0 W 0.0 SCSTR-55 Overall Synchronized Pre -Development Hyd graph mg (From Walgreers, Advanced Auto Parts & Pre -Development DI 1) 5.0 10.0 15.0 20.0 25.0 30.0 35.0 Synchronized Post -Development Hydrographs The following synchronized post -development hydrographs reflect the runoff entering the proposed UGD System #1, which outfalls directly to point of analysis #1. These hydrographs synchronize the Advance Auto Parts hydrographs, the Walgreens hydrographs and the DA 1 post -development hydrographs. These synchronized hydrographs are later inputted into this report's 'Proposed Maplewood Development's Underground Detention System #1 Routing Calculations' and reflect the proposed SWIVI facility's contributing watershed. The outflows from the proposed UGD system #1 routings were then used in the channel and flood protection computations. Overall Synchronized Post -Development Hydrograph, Combines the Walgreens & Advanced Auto Parts Outflow Hydrographs with the DA I Post-Dev. Inflow Hydrograph (Takes into account allen uation in the existing UGD systems at Advanced Auto Parts and Walgreens). 1-yr. 24-hr. SCS TR-55 Method Unit Hyd rograph for the la/P & Tc Listed Below Hyd rograph Time 1-yr Discharges (hrs.) (cls) 0.0 0.00 0.5 0.09 1.0 0.10 1.5 0.10 2.0 0.10 2.5 0.11 3.0 0.11 3.5 0.12 4.0 0.12 4.5 0.13 5.0 0.14 5.5 0.14 6.0 0.15 6.5 0.16 7.0 0.17 7.5 0.18 8.0 0.18 8.5 0.22 9.0 0.25 9.5 0.26 10.0 0.31 10.5 0.39 11.0 0.71 11.3 0.88 11.6 1.36 11.9 5.65 12.0 8.66 12.1 11.14 12.2 7.35 12.3 3.68 12.4 2.95 12.5 2.62 12.6 2.34 12.7 2.07 12.8 1.87 13.0 1.52 13.2 1.12 13.4 0.89 13.6 0.78 13.8 0.71 14.0 0.65 14.3 0.59 14.6 0.55 15.0 0.50 15.5 0.45 16.0 0.40 16.5 0.37 17.0 0.35 17.5 0.33 18.0 0.31 19.0 0.26 20.0 0.23 22.0 0.21 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30.5 0.00 31.0 0.00 12.00 10.00 8.0D 6.0D 4.0D 2.0D COD 0.0 SCS TR-55 Overall Synchronized Post -Development Hydrograph (Fmm Walgreens, Advanced Auto Part, & Post -Development DA 1) 5.0 10.0 15.0 20.0 25.0 30.0 35.0 Overall Synchronized Post -Development Hydrograph, Combines the Walgreens & Advanced Auto Parts Outflow Hydrographs with the DA I Post-Dev. Inflow Hydrograph (Takes into account allen uation in the existing UGD systems at Advanced Auto Parts and Walgreens). 2-yr. 24-hr. SCS TR-55 Method Unit Hyd rograph for the la/P & Tc Listed Below Hyd rograph Time 2-yr Discharges (hrs.) (cfs) 0.0 0.00 0.5 0.12 1.0 0.12 1.5 0.13 2.0 0.13 2.5 0.14 3.0 0.15 3.5 0.15 4.0 0.15 4.5 0.17 5.0 0.18 5.5 0.18 6.0 0.20 6.5 0.20 7.0 0.22 7.5 0.23 8.0 0.24 8.5 0.28 9.0 0.32 9.5 0.34 10.0 0.39 10.5 0.48 11.0 0.87 11.3 1.12 11.6 1.68 11.9 7.21 12.0 11.32 12.1 14.81 12.2 9.67 12.3 4.70 12.4 3.75 12.5 3.33 12.6 2.99 12.7 2.67 12.8 2.44 13.0 2.11 13.2 1.77 13.4 1.42 13.6 1.08 13.8 0.95 14.0 0.85 14.3 0.77 14.6 0.73 15.0 0.67 15.5 0.59 16.0 0.53 16.5 0.49 17.0 0.46 17.5 0.44 18.0 0.41 19.0 0.35 20.0 0.30 22.0 0.28 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30.5 0.00 31.0 0.00 ,�..0 14.00 12.00 10.00 8.0D 6.0D 4.0D 2.0D 0 On 0.0 SCS TR-55 Overall Synchronized Post -Development Hydrograph (Fmm Walgreens, Advanced Auto Part, & Post -Development DA 1) 5.0 10.0 15.0 20.0 25.0 30.0 35.0 Overall Synchronized Post -Development Hydrograph, Combines the Walgreens & Advanced Auto Parts Outflow Hydrographs with the DA I Post-Dev. Inflow Hydrograph (Takes into account allenuation in the existing UGD systems at Advanced Auto Parts and Walgreens). 10-yr. 24-hr. SCS TR-55 Method Unit Hydrograph for the la/P & Tc Listed Below Hyd rograph Time 10-yr Discharges (hrs.) (cfs) 0.0 0.00 0.5 0.10 1.0 0.10 1.5 0.10 2.0 0.11 2.5 0.11 3.0 0.12 3.5 0.12 4.0 0.13 4.5 0.14 5.0 0.15 5.5 0.15 6.0 0.16 6.5 0.17 7.0 0.18 7.5 0.19 8.0 0.20 8.5 0.23 9.0 0.28 9.5 0.29 10.0 0.34 10.5 0.44 11.0 1.06 11.3 1.47 11.6 2.37 11.9 14.45 12.0 21.78 12.1 36.38 12.2 22.26 12.3 8.01 12.4 5.49 12.5 4.60 12.6 3.89 12.7 3.25 12.8 2.88 13.0 2.51 13.2 2.17 13.4 1.95 13.6 1.75 13.8 1.60 14.0 1.45 14.3 1.30 14.6 1.23 15.0 1.11 15.5 1.00 16.0 0.88 16.5 0.81 17.0 0.77 17.5 0.73 18.0 0.69 19.0 0.58 20.0 0.50 22.0 0.46 26.0 0.00 26.5 0.00 27.0 0.00 27.5 0.00 28.0 0.00 28.5 0.00 29.0 0.00 29.5 0.00 30.0 0.00 30.5 0.00 31.0 0.00 4u.uu 35.00 30.00 25.00 20.00 15.00 10.00 5.00 000 0.0 SCS TR-55 Overall Synchronized Post -Development Hydrograph (Fmm Walgreens, Advanced Auto Part, & Post -Development DA 1) 5.0 10.0 15.0 20.0 25.0 30.0 35.0 Proposed Maplewood Development's Underground Detention System #1 Routing Calculations Maplewood Development UGD System No. 1 Routings BasinFlow printout INPUT: Basin: Maplewood Development UGD System No. 1 Routings 18 Contour Areas Elevation(ft) Area(sf) Computed Vol.(cy) 518.50 2147.00 0.0 519.00 2147.00 39.8 519.50 3362.00 90.3 520.00 3798.00 156.6 520.50 4083.00 229.6 521.00 4278.00 307.0 521.50 4407.00 387.4 522.00 4481.00 469.7 522.50 4506.00 552.9 523.00 4481.00 636.1 523.50 4407.00 718.4 524.00 4278.00 798.8 524.50 4083.00 876.2 525.00 3798.00 949.2 525.50 3362.00 1015.4 526.00 2147.00 1066.0 526.50 2147.00 1105.8 527.00 2147.00 1145.5 Start-Elevation(ft) 519.00 Vol.(cy) 6 Outlet Structures Outlet structure 0 Orifice name: Low -Flow Orifice area (sf) 0.180 diameter or depth (in) 5.750 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 519.000 multiple 1 discharge into riser Page 1 39.76 Outlet structure I Orifice Maplewood Development UGD System No. 1 Routings name: Mid Flow Orifices area (sf) 0.922 diameter or depth (in) 13.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 523.330 multiple 3 discharge into riser Outlet structure 2 Orifice name: High Flow Orifice area (sf) 0.785 diameter or depth (in) 12.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 525.000 multiple 1 discharge into riser Outlet structure 3 Weir name: Access Manhole for Inspection diameter (in) 24.000 side angle 0.000 coefficient 3.000 invert (ft) 528.100 multiple 1 discharge into riser Outlet structure 4 Orifice name: Str. 37- Primary Outlet area (sf) 1.767 diameter or depth (in) 18.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 518.970 multiple 1 discharge out of riser Page 2 Outlet structure 5 Orifice Maplewood Development UGD System No. 1 Routings name: Str. 41- Bypass Outlet area (sf) 1.227 diameter or depth (in) 15.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 524.750 multiple 1 discharge through dam 3 Inflow Hydrographs Hydrograph 0 Curve name: 1-yr 24-hr. SCS TR-55 Design Storm time incr (minlhrs) 0.01 time limit (minlhrs) 720.00 file: 1 yr SCS Synchronized Hydrograph.txt volume (cy) 1651.39 routed true time in hours true Hydrograph I Curve name: 2-yr 24-hr. SCS TR-55 Design Storm time incr (minlhrs) 0.01 time limit (minlhrs) 720.00 file: 2 yr SCS Synchronized Hydrograph.txt volume (cy) 2162.71 routed true time in hours true Hydrograph 2 Curve name: 10-yr 24-hr. SCS TR-55 Design Storm time incr (minlhrs) 0.01 time limit (minlhrs) 720.00 file: 10 yr SCS Synchronized Hydrograph.txt volume (cy) 3516.64 routed true time in hours true Page 3 Maplewood Development UGD System No. 1 Routings OUTPUT: Routing Method: storage -indication Hydrograph 0 Routing Summary of inflow (cfs) discharge (cfs) water level (ft) storage (cy) Hydrograph I Routing Summary of inflow (cfs) discharge (cfs) water level (ft) storage (cy) Hydrograph 2 Routing Summary of inflow (cfs) discharge (cfs) water level (ft) storage (cy) Peaks: 1-yr 24-hr 11.140 at 1.463 at 523.329 at 690.482 Peaks: 2-yr 24-hr 14.809 at 4.559 at 523.791 at 765.472 Peaks: 10-yr 24-hr 36.377 at 22.922 at 526.302 at 1090.025 Fri Oct 21 09:39:27 EDT 2022 SCS TR-55 Design Storm 12.10 (hrs) 12.97 (hrs) 13.00 (hrs) SCS TR-55 Design Storm 12.10 (hrs) 12.31 (hrs) 12.31 (hrs) SCS TR-55 Design Storm 12.10 (hrs) 12.20 (hrs) 12.20 (hrs) Page 4 Virginia Runoff Reduction Method Water Quality Calculations Lu� gd Peme� Name MapleviceA Deeelopme CLEAR ALL .�k .,e: 10/M/2022 Z023DmftR&&5,. .-Lavanad" Information Project (Treatment Volume and Wads) C.mavm. ..-I ea',ea 4A T'm.t RII w IT41 �.� (mvo �19,t TP —d le) "tJ ... c ... �b/acr — 0" 0,20 a, a, 0� M Post -Development Requirement for Site Area TP Load RedUdiGn Re,ui� (IbIW) I I -AND COVER SUM111ARY — POST DEVELOPMENT Laand C— surnma, T—.. 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