Agenda packet — Beaumont City Council, March 7, 2023 (part 3 of 6)

12:30 2.6 0.70 0.38 N/A 0.319 0.485 436.82 0.00 0.00 0.00 0.00 0.00 436.82 0.00 0.00 0.00 0.00 436.82 0.49 12:45 2.8 0.75 0.38 N/A 0.378 0.576 518.52 0.00 0.00 0.00 0.00 0.00 518.52 0.00 0.00 0.00 0.00 518.52 0.58 13:00 2.9 0.78 0.37 N/A 0.411 0.626 563.21 0.00 0.00 0.00 0.00 0.00 563.21 0.00 0.00 0.00 0.00 563.21 0.63 13:15 3.4 0.92 0.36 N/A 0.551 0.839 755.45 0.00 0.00 0.00 0.00 0.00 755.45 0.00 0.00 0.00 0.00 755.45 0.84 13:30 3.4 0.92 0.36 N/A 0.556 0.848 763.03 0.00 0.00 0.00 0.00 0.00 763.03 0.00 0.00 0.00 0.00 763.03 0.85 13:45 2.3 0.62 0.35 N/A 0.266 0.405 364.46 0.00 0.00 0.00 0.00 0.00 364.46 0.00 0.00 0.00 0.00 364.46 0.40 14:00 2.3 0.62 0.35 N/A 0.271 0.413 371.85 0.00 0.00 0.00 0.00 0.00 371.85 0.00 0.00 0.00 0.00 371.85 0.41 14:15 2.7 0.73 0.34 N/A 0.384 0.585 526.78 0.00 0.00 0.00 0.00 0.00 526.78 0.00 0.00 0.00 0.00 526.78 0.59 14:30 2.6 0.70 0.34 N/A 0.362 0.552 497.05 0.00 0.00 0.00 0.00 0.00 497.05 0.00 0.00 0.00 0.00 497.05 0.55 14:45 2.6 0.70 0.33 N/A 0.368 0.560 504.12 0.00 0.00 0.00 0.00 0.00 504.12 0.00 0.00 0.00 0.00 504.12 0.56 15:00 2.5 0.67 0.33 N/A 0.346 0.527 474.18 0.00 0.00 0.00 0.00 0.00 474.18 0.00 0.00 0.00 0.00 474.18 0.53 15:15 2.4 0.65 0.32 N/A 0.324 0.493 444.13 0.00 0.00 0.00 0.00 0.00 444.13 0.00 0.00 0.00 0.00 444.13 0.49 15:30 2.3 0.62 0.32 N/A 0.302 0.460 413.98 0.00 0.00 0.00 0.00 0.00 413.98 0.00 0.00 0.00 0.00 413.98 0.46 15:45 1.9 0.51 0.31 N/A 0.199 0.303 272.98 0.00 0.00 0.00 0.00 0.00 272.98 0.00 0.00 0.00 0.00 272.98 0.30 16:00 1.9 0.51 0.31 N/A 0.204 0.311 279.52 0.00 0.00 0.00 0.00 0.00 279.52 0.00 0.00 0.00 0.00 279.52 0.31 16:15 0.4 0.11 0.30 0.10 0.011 0.016 14.77 0.00 0.00 0.00 0.00 0.00 14.77 0.00 0.00 0.00 0.00 14.77 0.02 16:30 0.4 0.11 0.30 0.10 0.011 0.016 14.77 0.00 0.00 0.00 0.00 0.00 14.77 0.00 0.00 0.00 0.00 14.77 0.02 16:45 0.3 0.08 0.29 0.07 0.008 0.012 11.07 0.00 0.00 0.00 0.00 0.00 11.07 0.00 0.00 0.00 0.00 11.07 0.01 17:00 0.3 0.08 0.29 0.07 0.008 0.012 11.07 0.00 0.00 0.00 0.00 0.00 11.07 0.00 0.00 0.00 0.00 11.07 0.01 17:15 0.5 0.13 0.29 0.12 0.013 0.021 18.46 0.00 0.00 0.00 0.00 0.00 18.46 0.00 0.00 0.00 0.00 18.46 0.02 17:30 0.5 0.13 0.28 0.12 0.013 0.021 18.46 0.00 0.00 0.00 0.00 0.00 18.46 0.00 0.00 0.00 0.00 18.46 0.02 17:45 0.5 0.13 0.28 0.12 0.013 0.021 18.46 0.00 0.00 0.00 0.00 0.00 18.46 0.00 0.00 0.00 0.00 18.46 0.02 18:00 0.4 0.11 0.27 0.10 0.011 0.016 14.77 0.00 0.00 0.00 0.00 0.00 14.77 0.00 0.00 0.00 0.00 14.77 0.02 18:15 0.4 0.11 0.27 0.10 0.011 0.016 14.77 0.00 0.00 0.00 0.00 0.00 14.77 0.00 0.00 0.00 0.00 14.77 0.02 18:30 0.4 0.11 0.26 0.10 0.011 0.016 14.77 0.00 0.00 0.00 0.00 0.00 14.77 0.00 0.00 0.00 0.00 14.77 0.02 18:45 0.3 0.08 0.26 0.07 0.008 0.012 11.07 0.00 0.00 0.00 0.00 0.00 11.07 0.00 0.00 0.00 0.00 11.07 0.01 19:00 0.2 0.05 0.26 0.05 0.005 0.008 7.38 0.00 0.00 0.00 0.00 0.00 7.38 0.00 0.00 0.00 0.00 7.38 0.01 19:15 0.3 0.08 0.25 0.07 0.008 0.012 11.07 0.00 0.00 0.00 0.00 0.00 11.07 0.00 0.00 0.00 0.00 11.07 0.01 19:30 0.4 0.11 0.25 0.10 0.011 0.016 14.77 0.00 0.00 0.00 0.00 0.00 14.77 0.00 0.00 0.00 0.00 14.77 0.02 19:45 0.3 0.08 0.25 0.07 0.008 0.012 11.07 0.00 0.00 0.00 0.00 0.00 11.07 0.00 0.00 0.00 0.00 11.07 0.01 20:00 0.2 0.05 0.24 0.05 0.005 0.008 7.38 0.00 0.00 0.00 0.00 0.00 7.38 0.00 0.00 0.00 0.00 7.38 0.01 20:15 0.3 0.08 0.24 0.07 0.008 0.012 11.07 0.00 0.00 0.00 0.00 0.00 11.07 0.00 0.00 0.00 0.00 11.07 0.01 20:30 0.3 0.08 0.24 0.07 0.008 0.012 11.07 0.00 0.00 0.00 0.00 0.00 11.07 0.00 0.00 0.00 0.00 11.07 0.01 20:45 0.3 0.08 0.23 0.07 0.008 0.012 11.07 0.00 0.00 0.00 0.00 0.00 11.07 0.00 0.00 0.00 0.00 11.07 0.01 21:00 0.2 0.05 0.23 0.05 0.005 0.008 7.38 0.00 0.00 0.00 0.00 0.00 7.38 0.00 0.00 0.00 0.00 7.38 0.01 21:15 0.3 0.08 0.23 0.07 0.008 0.012 11.07 0.00 0.00 0.00 0.00 0.00 11.07 0.00 0.00 0.00 0.00 11.07 0.01 21:30 0.2 0.05 0.23 0.05 0.005 0.008 7.38 0.00 0.00 0.00 0.00 0.00 7.38 0.00 0.00 0.00 0.00 7.38 0.01 21:45 0.3 0.08 0.22 0.07 0.008 0.012 11.07 0.00 0.00 0.00 0.00 0.00 11.07 0.00 0.00 0.00 0.00 11.07 0.01 22:00 0.2 0.05 0.22 0.05 0.005 0.008 7.38 0.00 0.00 0.00 0.00 0.00 7.38 0.00 0.00 0.00 0.00 7.38 0.01 22:15 0.3 0.08 0.22 0.07 0.008 0.012 11.07 0.00 0.00 0.00 0.00 0.00 11.07 0.00 0.00 0.00 0.00 11.07 0.01 22:30 0.2 0.05 0.22 0.05 0.005 0.008 7.38 0.00 0.00 0.00 0.00 0.00 7.38 0.00 0.00 0.00 0.00 7.38 0.01 22:45 0.2 0.05 0.22 0.05 0.005 0.008 7.38 0.00 0.00 0.00 0.00 0.00 7.38 0.00 0.00 0.00 0.00 7.38 0.01 23:00 0.2 0.05 0.21 0.05 0.005 0.008 7.38 0.00 0.00 0.00 0.00 0.00 7.38 0.00 0.00 0.00 0.00 7.38 0.01 23:15 0.2 0.05 0.21 0.05 0.005 0.008 7.38 0.00 0.00 0.00 0.00 0.00 7.38 0.00 0.00 0.00 0.00 7.38 0.01 23:30 0.2 0.05 0.21 0.05 0.005 0.008 7.38 0.00 0.00 0.00 0.00 0.00 7.38 0.00 0.00 0.00 0.00 7.38 0.01 23:45 0.2 0.05 0.21 0.05 0.005 0.008 7.38 0.00 0.00 0.00 0.00 0.00 7.38 0.00 0.00 0.00 0.00 7.38 0.01 24:00 0.2 0.05 0.21 0.05 0.005 0.008 7.38 0.00 0.00 0.00 0.00 0.00 7.38 0.00 0.00 0.00 0.00 7.38 0.01 Total volume (CF)10394.72 Total Overflow (CF)10394.72
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F
Appendix F - Post-Development Hydrology Calculations
2-Year Frequency Storm Hydrology
5-year Frequency Strom Hydrology
10-Year Frequency Storm Hydrology
100-Year Frequency Storm Hydrology

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Project:Beaumont Post-Development
Recurrence Interval 2 year
Storm Duration (hrs)1 3 6 24
2-year NOAA Atlas 14 Point Precipitation (in)0.600 0.995 1.440 2.780 Unit time (minutes)5 5 5 15
Drainage Area 65819 SF 1.511 Ac.

Soils Group B
AMC index Runoff Number (plate E-6.1)36 Type:Urban Covers; good Pervious Area Loss Rate (Fp)(in/hr) (plate E-6.2)0.86 AMC I Percentage of Impervious Cover (Ai)(%) (plate E-6.3)83
Weighted Average Loss Rate (F=Fp(1-.9Ai))(in./hr.)0.22 (used for 1, 3, and 6 hour storm, the 24 hour storm uses variable maximum loss rate per plate E-1.1 (3 of 6)) Low Loss Rate Percent (%) 24
Percolation Rate (in/hr)1.00 (Used for retention basin and drywell) Percolation is taken incrementally.

Basin volume is calculated using the "truncated pyramid" formula, a more conservative estimate than "averaged end areas" sometimes used (Drywell can be "zeroed out" by reducing numbers to less than .001, but should not entered as zeros or program chokes.) Drywell storage includes 40% of the 1' wide rock bed surrounding the drywell: formula (upper)*PI()*(diam/2)^2+(lower)*PI()*((diam/2)^2+0.4*((diam/2+(grav+0.4166))^2-(diam/2+0.4166)^2)) The drywell wall thickness is assumed at 5" (0.4166) and the gravel bed width is variable "grav" Drywell design factors
Upper sec. (FT)=0.0001 Lower sec. (FT)=0.0001 Ring diam. (FT) =0.0001 Gravel bed width around drywell=0.0001 Drywell lower max. (CF)=0.00 Upper max.(CF)=0.00 Drywell total(CF)=0.00 Retention Basin design factors
Top (SF)=0.0001 Bot. (SF)=0.0001 Max. Depth (FT)=0.0001 Max. storage (CF)=0.00 (d/3)*(bottom+top+(bottom*top)^0.50) Formulas vol=(h/3)*(bottom+top+(bottom*top)^0.50) area=bottom+(h/d)*(top-bottom)h=(vol*3)/(bottom+top+(bottom*top)^0.5) 2 -year 1 Hour Storm in 5 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:05 3.7 0.27 0.22 0.06 0.203 0.309 92.83 0.00 0.00 0.00 0.00 0.00 92.83 0.00 0.00 0.00 0.00 92.83 0.31 0:10 4.8 0.35 0.22 0.08 0.263 0.401 120.43 0.00 0.00 0.00 0.00 0.00 120.43 0.00 0.00 0.00 0.00 120.43 0.40 0:15 5.1 0.37 0.22 0.09 0.280 0.427 127.96 0.00 0.00 0.00 0.00 0.00 127.96 0.00 0.00 0.00 0.00 127.96 0.43 0:20 4.9 0.35 0.22 0.08 0.269 0.410 122.94 0.00 0.00 0.00 0.00 0.00 122.94 0.00 0.00 0.00 0.00 122.94 0.41 0:25 6.6 0.48 0.22 0.11 0.362 0.552 165.60 0.00 0.00 0.00 0.00 0.00 165.60 0.00 0.00 0.00 0.00 165.60 0.55 0:30 7.3 0.53 0.22 0.12 0.401 0.611 183.16 0.00 0.00 0.00 0.00 0.00 183.16 0.00 0.00 0.00 0.00 183.16 0.61 0:35 8.4 0.60 0.22 0.14 0.461 0.703 210.76 0.00 0.00 0.00 0.00 0.00 210.76 0.00 0.00 0.00 0.00 210.76 0.70 0:40 9.0 0.65 0.22 0.15 0.494 0.753 225.81 0.00 0.00 0.00 0.00 0.00 225.81 0.00 0.00 0.00 0.00 225.81 0.75 0:45 12.3 0.89 0.22 0.21 0.675 1.029 308.61 0.00 0.00 0.00 0.00 0.00 308.61 0.00 0.00 0.00 0.00 308.61 1.03 0:50 17.6 1.27 0.22 N/A 1.048 1.597 479.05 0.00 0.00 0.00 0.00 0.00 479.05 0.00 0.00 0.00 0.00 479.05 1.60 0:55 16.1 1.16 0.22 N/A 0.940 1.432 429.68 0.00 0.00 0.00 0.00 0.00 429.68 0.00 0.00 0.00 0.00 429.68 1.43 1:00 4.2 0.30 0.22 0.07 0.231 0.351 105.38 0.00 0.00 0.00 0.00 0.00 105.38 0.00 0.00 0.00 0.00 105.38 0.35 Total volume (CF)2572.22 Total Overflow (CF)2572.22
RCFC&WCD Short Cut Unit Hydrograph Method
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2 -year 3 Hour Storm in 5 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:05 1.3 0.16 0.22 0.04 0.118 0.180 54.09 0.00 0.00 0.00 0.00 0.00 54.09 0.00 0.00 0.00 0.00 54.09 0.18 0:10 1.3 0.16 0.22 0.04 0.118 0.180 54.09 0.00 0.00 0.00 0.00 0.00 54.09 0.00 0.00 0.00 0.00 54.09 0.18 0:15 1.1 0.13 0.22 0.03 0.100 0.153 45.77 0.00 0.00 0.00 0.00 0.00 45.77 0.00 0.00 0.00 0.00 45.77 0.15 0:20 1.5 0.18 0.22 0.04 0.137 0.208 62.41 0.00 0.00 0.00 0.00 0.00 62.41 0.00 0.00 0.00 0.00 62.41 0.21 0:25 1.5 0.18 0.22 0.04 0.137 0.208 62.41 0.00 0.00 0.00 0.00 0.00 62.41 0.00 0.00 0.00 0.00 62.41 0.21 0:30 1.8 0.21 0.22 0.05 0.164 0.250 74.89 0.00 0.00 0.00 0.00 0.00 74.89 0.00 0.00 0.00 0.00 74.89 0.25 0:35 1.5 0.18 0.22 0.04 0.137 0.208 62.41 0.00 0.00 0.00 0.00 0.00 62.41 0.00 0.00 0.00 0.00 62.41 0.21 0:40 1.8 0.21 0.22 0.05 0.164 0.250 74.89 0.00 0.00 0.00 0.00 0.00 74.89 0.00 0.00 0.00 0.00 74.89 0.25 0:45 1.8 0.21 0.22 0.05 0.164 0.250 74.89 0.00 0.00 0.00 0.00 0.00 74.89 0.00 0.00 0.00 0.00 74.89 0.25 0:50 1.5 0.18 0.22 0.04 0.137 0.208 62.41 0.00 0.00 0.00 0.00 0.00 62.41 0.00 0.00 0.00 0.00 62.41 0.21 0:55 1.6 0.19 0.22 0.05 0.146 0.222 66.57 0.00 0.00 0.00 0.00 0.00 66.57 0.00 0.00 0.00 0.00 66.57 0.22 1:00 1.8 0.21 0.22 0.05 0.164 0.250 74.89 0.00 0.00 0.00 0.00 0.00 74.89 0.00 0.00 0.00 0.00 74.89 0.25 1:05 2.2 0.26 0.22 0.06 0.200 0.305 91.54 0.00 0.00 0.00 0.00 0.00 91.54 0.00 0.00 0.00 0.00 91.54 0.31 1:10 2.2 0.26 0.22 0.06 0.200 0.305 91.54 0.00 0.00 0.00 0.00 0.00 91.54 0.00 0.00 0.00 0.00 91.54 0.31 1:15 2.2 0.26 0.22 0.06 0.200 0.305 91.54 0.00 0.00 0.00 0.00 0.00 91.54 0.00 0.00 0.00 0.00 91.54 0.31 1:20 2.0 0.24 0.22 0.06 0.182 0.277 83.22 0.00 0.00 0.00 0.00 0.00 83.22 0.00 0.00 0.00 0.00 83.22 0.28 1:25 2.6 0.31 0.22 0.07 0.237 0.361 108.18 0.00 0.00 0.00 0.00 0.00 108.18 0.00 0.00 0.00 0.00 108.18 0.36 1:30 2.7 0.32 0.22 0.08 0.246 0.374 112.34 0.00 0.00 0.00 0.00 0.00 112.34 0.00 0.00 0.00 0.00 112.34 0.37 1:35 2.4 0.29 0.22 0.07 0.218 0.333 99.86 0.00 0.00 0.00 0.00 0.00 99.86 0.00 0.00 0.00 0.00 99.86 0.33 1:40 2.7 0.32 0.22 0.08 0.246 0.374 112.34 0.00 0.00 0.00 0.00 0.00 112.34 0.00 0.00 0.00 0.00 112.34 0.37 1:45 3.3 0.39 0.22 0.09 0.300 0.458 137.31 0.00 0.00 0.00 0.00 0.00 137.31 0.00 0.00 0.00 0.00 137.31 0.46 1:50 3.1 0.37 0.22 0.09 0.282 0.430 128.98 0.00 0.00 0.00 0.00 0.00 128.98 0.00 0.00 0.00 0.00 128.98 0.43 1:55 2.9 0.35 0.22 0.08 0.264 0.402 120.66 0.00 0.00 0.00 0.00 0.00 120.66 0.00 0.00 0.00 0.00 120.66 0.40 2:00 3.0 0.36 0.22 0.09 0.273 0.416 124.82 0.00 0.00 0.00 0.00 0.00 124.82 0.00 0.00 0.00 0.00 124.82 0.42 2:05 3.1 0.37 0.22 0.09 0.282 0.430 128.98 0.00 0.00 0.00 0.00 0.00 128.98 0.00 0.00 0.00 0.00 128.98 0.43 2:10 4.2 0.50 0.22 0.12 0.382 0.583 174.75 0.00 0.00 0.00 0.00 0.00 174.75 0.00 0.00 0.00 0.00 174.75 0.58 2:15 5.0 0.60 0.22 0.14 0.455 0.693 208.04 0.00 0.00 0.00 0.00 0.00 208.04 0.00 0.00 0.00 0.00 208.04 0.69 2:20 3.5 0.42 0.22 0.10 0.319 0.485 145.63 0.00 0.00 0.00 0.00 0.00 145.63 0.00 0.00 0.00 0.00 145.63 0.49 2:25 6.8 0.81 0.22 0.19 0.619 0.943 282.93 0.00 0.00 0.00 0.00 0.00 282.93 0.00 0.00 0.00 0.00 282.93 0.94 2:30 7.3 0.87 0.22 0.21 0.665 1.012 303.74 0.00 0.00 0.00 0.00 0.00 303.74 0.00 0.00 0.00 0.00 303.74 1.01 2:35 8.2 0.98 0.22 N/A 0.760 1.158 347.36 0.00 0.00 0.00 0.00 0.00 347.36 0.00 0.00 0.00 0.00 347.36 1.16 2:40 5.9 0.70 0.22 0.17 0.537 0.818 245.49 0.00 0.00 0.00 0.00 0.00 245.49 0.00 0.00 0.00 0.00 245.49 0.82 2:45 2.0 0.24 0.22 0.06 0.182 0.277 83.22 0.00 0.00 0.00 0.00 0.00 83.22 0.00 0.00 0.00 0.00 83.22 0.28 2:50 1.8 0.21 0.22 0.05 0.164 0.250 74.89 0.00 0.00 0.00 0.00 0.00 74.89 0.00 0.00 0.00 0.00 74.89 0.25 2:55 1.8 0.21 0.22 0.05 0.164 0.250 74.89 0.00 0.00 0.00 0.00 0.00 74.89 0.00 0.00 0.00 0.00 74.89 0.25 3:00 0.6 0.07 0.22 0.02 0.055 0.083 24.96 0.00 0.00 0.00 0.00 0.00 24.96 0.00 0.00 0.00 0.00 24.96 0.08 Total volume (CF)4166.97 Total Overflow (CF)4166.97
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2 -year 6 Hour Storm in 5 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:05 0.5 0.09 0.22 0.02 0.066 0.100 30.11 0.00 0.00 0.00 0.00 0.00 30.11 0.00 0.00 0.00 0.00 30.11 0.10 0:10 0.6 0.10 0.22 0.02 0.079 0.120 36.13 0.00 0.00 0.00 0.00 0.00 36.13 0.00 0.00 0.00 0.00 36.13 0.12 0:15 0.6 0.10 0.22 0.02 0.079 0.120 36.13 0.00 0.00 0.00 0.00 0.00 36.13 0.00 0.00 0.00 0.00 36.13 0.12 0:20 0.6 0.10 0.22 0.02 0.079 0.120 36.13 0.00 0.00 0.00 0.00 0.00 36.13 0.00 0.00 0.00 0.00 36.13 0.12 0:25 0.6 0.10 0.22 0.02 0.079 0.120 36.13 0.00 0.00 0.00 0.00 0.00 36.13 0.00 0.00 0.00 0.00 36.13 0.12 0:30 0.7 0.12 0.22 0.03 0.092 0.141 42.15 0.00 0.00 0.00 0.00 0.00 42.15 0.00 0.00 0.00 0.00 42.15 0.14 0:35 0.7 0.12 0.22 0.03 0.092 0.141 42.15 0.00 0.00 0.00 0.00 0.00 42.15 0.00 0.00 0.00 0.00 42.15 0.14 0:40 0.7 0.12 0.22 0.03 0.092 0.141 42.15 0.00 0.00 0.00 0.00 0.00 42.15 0.00 0.00 0.00 0.00 42.15 0.14 0:45 0.7 0.12 0.22 0.03 0.092 0.141 42.15 0.00 0.00 0.00 0.00 0.00 42.15 0.00 0.00 0.00 0.00 42.15 0.14 0:50 0.7 0.12 0.22 0.03 0.092 0.141 42.15 0.00 0.00 0.00 0.00 0.00 42.15 0.00 0.00 0.00 0.00 42.15 0.14 0:55 0.7 0.12 0.22 0.03 0.092 0.141 42.15 0.00 0.00 0.00 0.00 0.00 42.15 0.00 0.00 0.00 0.00 42.15 0.14 1:00 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 1:05 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 1:10 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 1:15 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 1:20 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 1:25 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 1:30 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 1:35 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 1:40 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 1:45 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 1:50 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 1:55 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 2:00 0.9 0.16 0.22 0.04 0.119 0.181 54.19 0.00 0.00 0.00 0.00 0.00 54.19 0.00 0.00 0.00 0.00 54.19 0.18 2:05 0.8 0.14 0.22 0.03 0.105 0.161 48.17 0.00 0.00 0.00 0.00 0.00 48.17 0.00 0.00 0.00 0.00 48.17 0.16 2:10 0.9 0.16 0.22 0.04 0.119 0.181 54.19 0.00 0.00 0.00 0.00 0.00 54.19 0.00 0.00 0.00 0.00 54.19 0.18 2:15 0.9 0.16 0.22 0.04 0.119 0.181 54.19 0.00 0.00 0.00 0.00 0.00 54.19 0.00 0.00 0.00 0.00 54.19 0.18 2:20 0.9 0.16 0.22 0.04 0.119 0.181 54.19 0.00 0.00 0.00 0.00 0.00 54.19 0.00 0.00 0.00 0.00 54.19 0.18 2:25 0.9 0.16 0.22 0.04 0.119 0.181 54.19 0.00 0.00 0.00 0.00 0.00 54.19 0.00 0.00 0.00 0.00 54.19 0.18 2:30 0.9 0.16 0.22 0.04 0.119 0.181 54.19 0.00 0.00 0.00 0.00 0.00 54.19 0.00 0.00 0.00 0.00 54.19 0.18 2:35 0.9 0.16 0.22 0.04 0.119 0.181 54.19 0.00 0.00 0.00 0.00 0.00 54.19 0.00 0.00 0.00 0.00 54.19 0.18 2:40 0.9 0.16 0.22 0.04 0.119 0.181 54.19 0.00 0.00 0.00 0.00 0.00 54.19 0.00 0.00 0.00 0.00 54.19 0.18 2:45 1.0 0.17 0.22 0.04 0.132 0.201 60.22 0.00 0.00 0.00 0.00 0.00 60.22 0.00 0.00 0.00 0.00 60.22 0.20 2:50 1.0 0.17 0.22 0.04 0.132 0.201 60.22 0.00 0.00 0.00 0.00 0.00 60.22 0.00 0.00 0.00 0.00 60.22 0.20 2:55 1.0 0.17 0.22 0.04 0.132 0.201 60.22 0.00 0.00 0.00 0.00 0.00 60.22 0.00 0.00 0.00 0.00 60.22 0.20 3:00 1.0 0.17 0.22 0.04 0.132 0.201 60.22 0.00 0.00 0.00 0.00 0.00 60.22 0.00 0.00 0.00 0.00 60.22 0.20 3:05 1.0 0.17 0.22 0.04 0.132 0.201 60.22 0.00 0.00 0.00 0.00 0.00 60.22 0.00 0.00 0.00 0.00 60.22 0.20 3:10 1.1 0.19 0.22 0.05 0.145 0.221 66.24 0.00 0.00 0.00 0.00 0.00 66.24 0.00 0.00 0.00 0.00 66.24 0.22 3:15 1.1 0.19 0.22 0.05 0.145 0.221 66.24 0.00 0.00 0.00 0.00 0.00 66.24 0.00 0.00 0.00 0.00 66.24 0.22 3:20 1.1 0.19 0.22 0.05 0.145 0.221 66.24 0.00 0.00 0.00 0.00 0.00 66.24 0.00 0.00 0.00 0.00 66.24 0.22 3:25 1.2 0.21 0.22 0.05 0.158 0.241 72.26 0.00 0.00 0.00 0.00 0.00 72.26 0.00 0.00 0.00 0.00 72.26 0.24 3:30 1.3 0.22 0.22 0.05 0.171 0.261 78.28 0.00 0.00 0.00 0.00 0.00 78.28 0.00 0.00 0.00 0.00 78.28 0.26 3:35 1.4 0.24 0.22 0.06 0.184 0.281 84.30 0.00 0.00 0.00 0.00 0.00 84.30 0.00 0.00 0.00 0.00 84.30 0.28 3:40 1.4 0.24 0.22 0.06 0.184 0.281 84.30 0.00 0.00 0.00 0.00 0.00 84.30 0.00 0.00 0.00 0.00 84.30 0.28 3:45 1.5 0.26 0.22 0.06 0.198 0.301 90.32 0.00 0.00 0.00 0.00 0.00 90.32 0.00 0.00 0.00 0.00 90.32 0.30 3:50 1.5 0.26 0.22 0.06 0.198 0.301 90.32 0.00 0.00 0.00 0.00 0.00 90.32 0.00 0.00 0.00 0.00 90.32 0.30 3:55 1.6 0.28 0.22 0.07 0.211 0.321 96.35 0.00 0.00 0.00 0.00 0.00 96.35 0.00 0.00 0.00 0.00 96.35 0.32 4:00 1.6 0.28 0.22 0.07 0.211 0.321 96.35 0.00 0.00 0.00 0.00 0.00 96.35 0.00 0.00 0.00 0.00 96.35 0.32 4:05 1.7 0.29 0.22 0.07 0.224 0.341 102.37 0.00 0.00 0.00 0.00 0.00 102.37 0.00 0.00 0.00 0.00 102.37 0.34 3 of 24

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4:10 1.8 0.31 0.22 0.07 0.237 0.361 108.39 0.00 0.00 0.00 0.00 0.00 108.39 0.00 0.00 0.00 0.00 108.39 0.36 4:15 1.9 0.33 0.22 0.08 0.250 0.381 114.41 0.00 0.00 0.00 0.00 0.00 114.41 0.00 0.00 0.00 0.00 114.41 0.38 4:20 2.0 0.35 0.22 0.08 0.263 0.401 120.43 0.00 0.00 0.00 0.00 0.00 120.43 0.00 0.00 0.00 0.00 120.43 0.40 4:25 2.1 0.36 0.22 0.09 0.277 0.422 126.45 0.00 0.00 0.00 0.00 0.00 126.45 0.00 0.00 0.00 0.00 126.45 0.42 4:30 2.1 0.36 0.22 0.09 0.277 0.422 126.45 0.00 0.00 0.00 0.00 0.00 126.45 0.00 0.00 0.00 0.00 126.45 0.42 4:35 2.2 0.38 0.22 0.09 0.290 0.442 132.48 0.00 0.00 0.00 0.00 0.00 132.48 0.00 0.00 0.00 0.00 132.48 0.44 4:40 2.3 0.40 0.22 0.09 0.303 0.462 138.50 0.00 0.00 0.00 0.00 0.00 138.50 0.00 0.00 0.00 0.00 138.50 0.46 4:45 2.4 0.41 0.22 0.10 0.316 0.482 144.52 0.00 0.00 0.00 0.00 0.00 144.52 0.00 0.00 0.00 0.00 144.52 0.48 4:50 2.4 0.41 0.22 0.10 0.316 0.482 144.52 0.00 0.00 0.00 0.00 0.00 144.52 0.00 0.00 0.00 0.00 144.52 0.48 4:55 2.5 0.43 0.22 0.10 0.329 0.502 150.54 0.00 0.00 0.00 0.00 0.00 150.54 0.00 0.00 0.00 0.00 150.54 0.50 5:00 2.6 0.45 0.22 0.11 0.343 0.522 156.56 0.00 0.00 0.00 0.00 0.00 156.56 0.00 0.00 0.00 0.00 156.56 0.52 5:05 3.1 0.54 0.22 0.13 0.408 0.622 186.67 0.00 0.00 0.00 0.00 0.00 186.67 0.00 0.00 0.00 0.00 186.67 0.62 5:10 3.6 0.62 0.22 0.15 0.474 0.723 216.78 0.00 0.00 0.00 0.00 0.00 216.78 0.00 0.00 0.00 0.00 216.78 0.72 5:15 3.9 0.67 0.22 0.16 0.514 0.783 234.84 0.00 0.00 0.00 0.00 0.00 234.84 0.00 0.00 0.00 0.00 234.84 0.78 5:20 4.2 0.73 0.22 0.17 0.553 0.843 252.91 0.00 0.00 0.00 0.00 0.00 252.91 0.00 0.00 0.00 0.00 252.91 0.84 5:25 4.7 0.81 0.22 0.19 0.619 0.943 283.02 0.00 0.00 0.00 0.00 0.00 283.02 0.00 0.00 0.00 0.00 283.02 0.94 5:30 5.6 0.97 0.22 N/A 0.749 1.140 342.15 0.00 0.00 0.00 0.00 0.00 342.15 0.00 0.00 0.00 0.00 342.15 1.14 5:35 1.9 0.33 0.22 0.08 0.250 0.381 114.41 0.00 0.00 0.00 0.00 0.00 114.41 0.00 0.00 0.00 0.00 114.41 0.38 5:40 0.9 0.16 0.22 0.04 0.119 0.181 54.19 0.00 0.00 0.00 0.00 0.00 54.19 0.00 0.00 0.00 0.00 54.19 0.18 5:45 0.6 0.10 0.22 0.02 0.079 0.120 36.13 0.00 0.00 0.00 0.00 0.00 36.13 0.00 0.00 0.00 0.00 36.13 0.12 5:50 0.5 0.09 0.22 0.02 0.066 0.100 30.11 0.00 0.00 0.00 0.00 0.00 30.11 0.00 0.00 0.00 0.00 30.11 0.10 5:55 0.3 0.05 0.22 0.01 0.040 0.060 18.06 0.00 0.00 0.00 0.00 0.00 18.06 0.00 0.00 0.00 0.00 18.06 0.06 6:00 0.2 0.03 0.22 0.01 0.026 0.040 12.04 0.00 0.00 0.00 0.00 0.00 12.04 0.00 0.00 0.00 0.00 12.04 0.04 Total volume (CF)6026.59 Total Overflow (CF)6026.59
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2 -year 24 Hour Storm in 15 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:15 0.2 0.02 0.38 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 0:30 0.3 0.03 0.38 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 0:45 0.3 0.03 0.38 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 1:00 0.4 0.04 0.37 0.01 0.034 0.052 46.50 0.00 0.00 0.00 0.00 0.00 46.50 0.00 0.00 0.00 0.00 46.50 0.05 1:15 0.3 0.03 0.37 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 1:30 0.3 0.03 0.36 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 1:45 0.3 0.03 0.36 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 2:00 0.4 0.04 0.35 0.01 0.034 0.052 46.50 0.00 0.00 0.00 0.00 0.00 46.50 0.00 0.00 0.00 0.00 46.50 0.05 2:15 0.4 0.04 0.35 0.01 0.034 0.052 46.50 0.00 0.00 0.00 0.00 0.00 46.50 0.00 0.00 0.00 0.00 46.50 0.05 2:30 0.4 0.04 0.35 0.01 0.034 0.052 46.50 0.00 0.00 0.00 0.00 0.00 46.50 0.00 0.00 0.00 0.00 46.50 0.05 2:45 0.5 0.06 0.34 0.01 0.042 0.065 58.13 0.00 0.00 0.00 0.00 0.00 58.13 0.00 0.00 0.00 0.00 58.13 0.06 3:00 0.5 0.06 0.34 0.01 0.042 0.065 58.13 0.00 0.00 0.00 0.00 0.00 58.13 0.00 0.00 0.00 0.00 58.13 0.06 3:15 0.5 0.06 0.33 0.01 0.042 0.065 58.13 0.00 0.00 0.00 0.00 0.00 58.13 0.00 0.00 0.00 0.00 58.13 0.06 3:30 0.5 0.06 0.33 0.01 0.042 0.065 58.13 0.00 0.00 0.00 0.00 0.00 58.13 0.00 0.00 0.00 0.00 58.13 0.06 3:45 0.5 0.06 0.32 0.01 0.042 0.065 58.13 0.00 0.00 0.00 0.00 0.00 58.13 0.00 0.00 0.00 0.00 58.13 0.06 4:00 0.6 0.07 0.32 0.02 0.051 0.078 69.75 0.00 0.00 0.00 0.00 0.00 69.75 0.00 0.00 0.00 0.00 69.75 0.08 4:15 0.6 0.07 0.32 0.02 0.051 0.078 69.75 0.00 0.00 0.00 0.00 0.00 69.75 0.00 0.00 0.00 0.00 69.75 0.08 4:30 0.7 0.08 0.31 0.02 0.059 0.090 81.38 0.00 0.00 0.00 0.00 0.00 81.38 0.00 0.00 0.00 0.00 81.38 0.09 4:45 0.7 0.08 0.31 0.02 0.059 0.090 81.38 0.00 0.00 0.00 0.00 0.00 81.38 0.00 0.00 0.00 0.00 81.38 0.09 5:00 0.8 0.09 0.30 0.02 0.068 0.103 93.00 0.00 0.00 0.00 0.00 0.00 93.00 0.00 0.00 0.00 0.00 93.00 0.10 5:15 0.6 0.07 0.30 0.02 0.051 0.078 69.75 0.00 0.00 0.00 0.00 0.00 69.75 0.00 0.00 0.00 0.00 69.75 0.08 5:30 0.7 0.08 0.30 0.02 0.059 0.090 81.38 0.00 0.00 0.00 0.00 0.00 81.38 0.00 0.00 0.00 0.00 81.38 0.09 5:45 0.8 0.09 0.29 0.02 0.068 0.103 93.00 0.00 0.00 0.00 0.00 0.00 93.00 0.00 0.00 0.00 0.00 93.00 0.10 6:00 0.8 0.09 0.29 0.02 0.068 0.103 93.00 0.00 0.00 0.00 0.00 0.00 93.00 0.00 0.00 0.00 0.00 93.00 0.10 6:15 0.9 0.10 0.28 0.02 0.076 0.116 104.63 0.00 0.00 0.00 0.00 0.00 104.63 0.00 0.00 0.00 0.00 104.63 0.12 6:30 0.9 0.10 0.28 0.02 0.076 0.116 104.63 0.00 0.00 0.00 0.00 0.00 104.63 0.00 0.00 0.00 0.00 104.63 0.12 6:45 1.0 0.11 0.28 0.03 0.085 0.129 116.25 0.00 0.00 0.00 0.00 0.00 116.25 0.00 0.00 0.00 0.00 116.25 0.13 7:00 1.0 0.11 0.27 0.03 0.085 0.129 116.25 0.00 0.00 0.00 0.00 0.00 116.25 0.00 0.00 0.00 0.00 116.25 0.13 7:15 1.0 0.11 0.27 0.03 0.085 0.129 116.25 0.00 0.00 0.00 0.00 0.00 116.25 0.00 0.00 0.00 0.00 116.25 0.13 7:30 1.1 0.12 0.27 0.03 0.093 0.142 127.88 0.00 0.00 0.00 0.00 0.00 127.88 0.00 0.00 0.00 0.00 127.88 0.14 7:45 1.2 0.13 0.26 0.03 0.102 0.155 139.50 0.00 0.00 0.00 0.00 0.00 139.50 0.00 0.00 0.00 0.00 139.50 0.16 8:00 1.3 0.14 0.26 0.03 0.110 0.168 151.13 0.00 0.00 0.00 0.00 0.00 151.13 0.00 0.00 0.00 0.00 151.13 0.17 8:15 1.5 0.17 0.26 0.04 0.127 0.194 174.38 0.00 0.00 0.00 0.00 0.00 174.38 0.00 0.00 0.00 0.00 174.38 0.19 8:30 1.5 0.17 0.25 0.04 0.127 0.194 174.38 0.00 0.00 0.00 0.00 0.00 174.38 0.00 0.00 0.00 0.00 174.38 0.19 8:45 1.6 0.18 0.25 0.04 0.136 0.207 186.00 0.00 0.00 0.00 0.00 0.00 186.00 0.00 0.00 0.00 0.00 186.00 0.21 9:00 1.7 0.19 0.24 0.04 0.144 0.220 197.63 0.00 0.00 0.00 0.00 0.00 197.63 0.00 0.00 0.00 0.00 197.63 0.22 9:15 1.9 0.21 0.24 0.05 0.161 0.245 220.88 0.00 0.00 0.00 0.00 0.00 220.88 0.00 0.00 0.00 0.00 220.88 0.25 9:30 2.0 0.22 0.24 0.05 0.170 0.258 232.50 0.00 0.00 0.00 0.00 0.00 232.50 0.00 0.00 0.00 0.00 232.50 0.26 9:45 2.1 0.23 0.23 0.06 0.178 0.271 244.13 0.00 0.00 0.00 0.00 0.00 244.13 0.00 0.00 0.00 0.00 244.13 0.27 10:00 2.2 0.24 0.23 0.06 0.187 0.284 255.75 0.00 0.00 0.00 0.00 0.00 255.75 0.00 0.00 0.00 0.00 255.75 0.28 10:15 1.5 0.17 0.23 0.04 0.127 0.194 174.38 0.00 0.00 0.00 0.00 0.00 174.38 0.00 0.00 0.00 0.00 174.38 0.19 10:30 1.5 0.17 0.22 0.04 0.127 0.194 174.38 0.00 0.00 0.00 0.00 0.00 174.38 0.00 0.00 0.00 0.00 174.38 0.19 10:45 2.0 0.22 0.22 0.05 0.170 0.258 232.50 0.00 0.00 0.00 0.00 0.00 232.50 0.00 0.00 0.00 0.00 232.50 0.26 11:00 2.0 0.22 0.22 0.05 0.170 0.258 232.50 0.00 0.00 0.00 0.00 0.00 232.50 0.00 0.00 0.00 0.00 232.50 0.26 11:15 1.9 0.21 0.21 0.05 0.161 0.245 220.88 0.00 0.00 0.00 0.00 0.00 220.88 0.00 0.00 0.00 0.00 220.88 0.25 11:30 1.9 0.21 0.21 0.05 0.161 0.245 220.88 0.00 0.00 0.00 0.00 0.00 220.88 0.00 0.00 0.00 0.00 220.88 0.25 11:45 1.7 0.19 0.21 0.04 0.144 0.220 197.63 0.00 0.00 0.00 0.00 0.00 197.63 0.00 0.00 0.00 0.00 197.63 0.22 12:00 1.8 0.20 0.21 0.05 0.153 0.233 209.25 0.00 0.00 0.00 0.00 0.00 209.25 0.00 0.00 0.00 0.00 209.25 0.23 12:15 2.5 0.28 0.20 0.07 0.212 0.323 290.63 0.00 0.00 0.00 0.00 0.00 290.63 0.00 0.00 0.00 0.00 290.63 0.32 5 of 24

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12:30 2.6 0.29 0.20 0.07 0.220 0.336 302.25 0.00 0.00 0.00 0.00 0.00 302.25 0.00 0.00 0.00 0.00 302.25 0.34 12:45 2.8 0.31 0.20 0.07 0.237 0.362 325.50 0.00 0.00 0.00 0.00 0.00 325.50 0.00 0.00 0.00 0.00 325.50 0.36 13:00 2.9 0.32 0.19 0.08 0.246 0.375 337.13 0.00 0.00 0.00 0.00 0.00 337.13 0.00 0.00 0.00 0.00 337.13 0.37 13:15 3.4 0.38 0.19 0.09 0.288 0.439 395.25 0.00 0.00 0.00 0.00 0.00 395.25 0.00 0.00 0.00 0.00 395.25 0.44 13:30 3.4 0.38 0.19 0.09 0.288 0.439 395.25 0.00 0.00 0.00 0.00 0.00 395.25 0.00 0.00 0.00 0.00 395.25 0.44 13:45 2.3 0.26 0.18 0.06 0.195 0.297 267.38 0.00 0.00 0.00 0.00 0.00 267.38 0.00 0.00 0.00 0.00 267.38 0.30 14:00 2.3 0.26 0.18 0.06 0.195 0.297 267.38 0.00 0.00 0.00 0.00 0.00 267.38 0.00 0.00 0.00 0.00 267.38 0.30 14:15 2.7 0.30 0.18 0.07 0.229 0.349 313.88 0.00 0.00 0.00 0.00 0.00 313.88 0.00 0.00 0.00 0.00 313.88 0.35 14:30 2.6 0.29 0.18 0.07 0.220 0.336 302.25 0.00 0.00 0.00 0.00 0.00 302.25 0.00 0.00 0.00 0.00 302.25 0.34 14:45 2.6 0.29 0.17 0.07 0.220 0.336 302.25 0.00 0.00 0.00 0.00 0.00 302.25 0.00 0.00 0.00 0.00 302.25 0.34 15:00 2.5 0.28 0.17 0.07 0.212 0.323 290.63 0.00 0.00 0.00 0.00 0.00 290.63 0.00 0.00 0.00 0.00 290.63 0.32 15:15 2.4 0.27 0.17 0.06 0.203 0.310 279.00 0.00 0.00 0.00 0.00 0.00 279.00 0.00 0.00 0.00 0.00 279.00 0.31 15:30 2.3 0.26 0.17 0.06 0.195 0.297 267.38 0.00 0.00 0.00 0.00 0.00 267.38 0.00 0.00 0.00 0.00 267.38 0.30 15:45 1.9 0.21 0.16 0.05 0.161 0.245 220.88 0.00 0.00 0.00 0.00 0.00 220.88 0.00 0.00 0.00 0.00 220.88 0.25 16:00 1.9 0.21 0.16 0.05 0.161 0.245 220.88 0.00 0.00 0.00 0.00 0.00 220.88 0.00 0.00 0.00 0.00 220.88 0.25 16:15 0.4 0.04 0.16 0.01 0.034 0.052 46.50 0.00 0.00 0.00 0.00 0.00 46.50 0.00 0.00 0.00 0.00 46.50 0.05 16:30 0.4 0.04 0.16 0.01 0.034 0.052 46.50 0.00 0.00 0.00 0.00 0.00 46.50 0.00 0.00 0.00 0.00 46.50 0.05 16:45 0.3 0.03 0.15 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 17:00 0.3 0.03 0.15 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 17:15 0.5 0.06 0.15 0.01 0.042 0.065 58.13 0.00 0.00 0.00 0.00 0.00 58.13 0.00 0.00 0.00 0.00 58.13 0.06 17:30 0.5 0.06 0.15 0.01 0.042 0.065 58.13 0.00 0.00 0.00 0.00 0.00 58.13 0.00 0.00 0.00 0.00 58.13 0.06 17:45 0.5 0.06 0.14 0.01 0.042 0.065 58.13 0.00 0.00 0.00 0.00 0.00 58.13 0.00 0.00 0.00 0.00 58.13 0.06 18:00 0.4 0.04 0.14 0.01 0.034 0.052 46.50 0.00 0.00 0.00 0.00 0.00 46.50 0.00 0.00 0.00 0.00 46.50 0.05 18:15 0.4 0.04 0.14 0.01 0.034 0.052 46.50 0.00 0.00 0.00 0.00 0.00 46.50 0.00 0.00 0.00 0.00 46.50 0.05 18:30 0.4 0.04 0.14 0.01 0.034 0.052 46.50 0.00 0.00 0.00 0.00 0.00 46.50 0.00 0.00 0.00 0.00 46.50 0.05 18:45 0.3 0.03 0.14 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 19:00 0.2 0.02 0.13 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 19:15 0.3 0.03 0.13 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 19:30 0.4 0.04 0.13 0.01 0.034 0.052 46.50 0.00 0.00 0.00 0.00 0.00 46.50 0.00 0.00 0.00 0.00 46.50 0.05 19:45 0.3 0.03 0.13 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 20:00 0.2 0.02 0.13 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 20:15 0.3 0.03 0.13 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 20:30 0.3 0.03 0.12 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 20:45 0.3 0.03 0.12 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 21:00 0.2 0.02 0.12 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 21:15 0.3 0.03 0.12 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 21:30 0.2 0.02 0.12 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 21:45 0.3 0.03 0.12 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 22:00 0.2 0.02 0.12 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 22:15 0.3 0.03 0.11 0.01 0.025 0.039 34.88 0.00 0.00 0.00 0.00 0.00 34.88 0.00 0.00 0.00 0.00 34.88 0.04 22:30 0.2 0.02 0.11 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 22:45 0.2 0.02 0.11 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 23:00 0.2 0.02 0.11 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 23:15 0.2 0.02 0.11 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 23:30 0.2 0.02 0.11 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 23:45 0.2 0.02 0.11 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 24:00 0.2 0.02 0.11 0.01 0.017 0.026 23.25 0.00 0.00 0.00 0.00 0.00 23.25 0.00 0.00 0.00 0.00 23.25 0.03 Total volume (CF)11625.13 Total Overflow (CF)11625.13
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Project:Beaumont Post-Development
Recurrence Interval 5 year
Storm Duration (hrs)1 3 6 24
5-year NOAA Atlas 14 Point Precipitation (in)0.811 1.270 1.810 3.620 Unit time (minutes)5 5 5 15
Drainage Area 65819 SF 1.511 Ac.

Basin volume is calculated using the "truncated pyramid" formula, a more conservative estimate than "averaged end areas" sometimes used (Drywell can be "zeroed out" by reducing numbers to less than .001, but should not entered as zeros or program chokes.) Drywell storage includes 40% of the 1' wide rock bed surrounding the drywell: formula (upper)*PI()*(diam/2)^2+(lower)*PI()*((diam/2)^2+0.4*((diam/2+(grav+0.4166))^2-(diam/2+0.4166)^2)) The drywell wall thickness is assumed at 5" (0.4166) and the gravel bed width is variable "grav" Drywell design factors
Upper sec. (FT)=0.0001 Lower sec. (FT)=0.0001 Ring diam. (FT) =0.0001 Gravel bed width around drywell=0.0001 Drywell lower max. (CF)=0.00 Upper max.(CF)=0.00 Drywell total(CF)=0.00 Retention Basin design factors
Top (SF)=0.0001 Bot. (SF)=0.0001 Max. Depth (FT)=0.0001 Max. storage (CF)=0.00 (d/3)*(bottom+top+(bottom*top)^0.50) Formulas vol=(h/3)*(bottom+top+(bottom*top)^0.50) area=bottom+(h/d)*(top-bottom)h=(vol*3)/(bottom+top+(bottom*top)^0.5) 5 -year 1 Hour Storm in 5 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:05 3.7 0.36 0.22 0.09 0.275 0.418 125.48 0.00 0.00 0.00 0.00 0.00 125.48 0.00 0.00 0.00 0.00 125.48 0.42 0:10 4.8 0.47 0.22 0.11 0.356 0.543 162.79 0.00 0.00 0.00 0.00 0.00 162.79 0.00 0.00 0.00 0.00 162.79 0.54 0:15 5.1 0.50 0.22 0.12 0.378 0.577 172.96 0.00 0.00 0.00 0.00 0.00 172.96 0.00 0.00 0.00 0.00 172.96 0.58 0:20 4.9 0.48 0.22 0.11 0.364 0.554 166.18 0.00 0.00 0.00 0.00 0.00 166.18 0.00 0.00 0.00 0.00 166.18 0.55 0:25 6.6 0.64 0.22 0.15 0.490 0.746 223.83 0.00 0.00 0.00 0.00 0.00 223.83 0.00 0.00 0.00 0.00 223.83 0.75 0:30 7.3 0.71 0.22 0.17 0.542 0.825 247.57 0.00 0.00 0.00 0.00 0.00 247.57 0.00 0.00 0.00 0.00 247.57 0.83 0:35 8.4 0.82 0.22 0.19 0.623 0.950 284.87 0.00 0.00 0.00 0.00 0.00 284.87 0.00 0.00 0.00 0.00 284.87 0.95 0:40 9.0 0.88 0.22 0.21 0.668 1.017 305.22 0.00 0.00 0.00 0.00 0.00 305.22 0.00 0.00 0.00 0.00 305.22 1.02 0:45 12.3 1.20 0.22 N/A 0.978 1.490 446.98 0.00 0.00 0.00 0.00 0.00 446.98 0.00 0.00 0.00 0.00 446.98 1.49 0:50 17.6 1.71 0.22 N/A 1.494 2.276 682.74 0.00 0.00 0.00 0.00 0.00 682.74 0.00 0.00 0.00 0.00 682.74 2.28 0:55 16.1 1.57 0.22 N/A 1.348 2.053 616.01 0.00 0.00 0.00 0.00 0.00 616.01 0.00 0.00 0.00 0.00 616.01 2.05 1:00 4.2 0.41 0.22 0.10 0.312 0.475 142.44 0.00 0.00 0.00 0.00 0.00 142.44 0.00 0.00 0.00 0.00 142.44 0.47 Total volume (CF)3577.06 Total Overflow (CF)3577.06
RCFC&WCD Short Cut Unit Hydrograph Method
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5 -year 3 Hour Storm in 5 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:05 1.3 0.20 0.22 0.05 0.151 0.230 69.04 0.00 0.00 0.00 0.00 0.00 69.04 0.00 0.00 0.00 0.00 69.04 0.23 0:10 1.3 0.20 0.22 0.05 0.151 0.230 69.04 0.00 0.00 0.00 0.00 0.00 69.04 0.00 0.00 0.00 0.00 69.04 0.23 0:15 1.1 0.17 0.22 0.04 0.128 0.195 58.42 0.00 0.00 0.00 0.00 0.00 58.42 0.00 0.00 0.00 0.00 58.42 0.19 0:20 1.5 0.23 0.22 0.05 0.174 0.266 79.66 0.00 0.00 0.00 0.00 0.00 79.66 0.00 0.00 0.00 0.00 79.66 0.27 0:25 1.5 0.23 0.22 0.05 0.174 0.266 79.66 0.00 0.00 0.00 0.00 0.00 79.66 0.00 0.00 0.00 0.00 79.66 0.27 0:30 1.8 0.27 0.22 0.07 0.209 0.319 95.59 0.00 0.00 0.00 0.00 0.00 95.59 0.00 0.00 0.00 0.00 95.59 0.32 0:35 1.5 0.23 0.22 0.05 0.174 0.266 79.66 0.00 0.00 0.00 0.00 0.00 79.66 0.00 0.00 0.00 0.00 79.66 0.27 0:40 1.8 0.27 0.22 0.07 0.209 0.319 95.59 0.00 0.00 0.00 0.00 0.00 95.59 0.00 0.00 0.00 0.00 95.59 0.32 0:45 1.8 0.27 0.22 0.07 0.209 0.319 95.59 0.00 0.00 0.00 0.00 0.00 95.59 0.00 0.00 0.00 0.00 95.59 0.32 0:50 1.5 0.23 0.22 0.05 0.174 0.266 79.66 0.00 0.00 0.00 0.00 0.00 79.66 0.00 0.00 0.00 0.00 79.66 0.27 0:55 1.6 0.24 0.22 0.06 0.186 0.283 84.97 0.00 0.00 0.00 0.00 0.00 84.97 0.00 0.00 0.00 0.00 84.97 0.28 1:00 1.8 0.27 0.22 0.07 0.209 0.319 95.59 0.00 0.00 0.00 0.00 0.00 95.59 0.00 0.00 0.00 0.00 95.59 0.32 1:05 2.2 0.34 0.22 0.08 0.256 0.389 116.84 0.00 0.00 0.00 0.00 0.00 116.84 0.00 0.00 0.00 0.00 116.84 0.39 1:10 2.2 0.34 0.22 0.08 0.256 0.389 116.84 0.00 0.00 0.00 0.00 0.00 116.84 0.00 0.00 0.00 0.00 116.84 0.39 1:15 2.2 0.34 0.22 0.08 0.256 0.389 116.84 0.00 0.00 0.00 0.00 0.00 116.84 0.00 0.00 0.00 0.00 116.84 0.39 1:20 2.0 0.30 0.22 0.07 0.232 0.354 106.22 0.00 0.00 0.00 0.00 0.00 106.22 0.00 0.00 0.00 0.00 106.22 0.35 1:25 2.6 0.40 0.22 0.09 0.302 0.460 138.08 0.00 0.00 0.00 0.00 0.00 138.08 0.00 0.00 0.00 0.00 138.08 0.46 1:30 2.7 0.41 0.22 0.10 0.314 0.478 143.39 0.00 0.00 0.00 0.00 0.00 143.39 0.00 0.00 0.00 0.00 143.39 0.48 1:35 2.4 0.37 0.22 0.09 0.279 0.425 127.46 0.00 0.00 0.00 0.00 0.00 127.46 0.00 0.00 0.00 0.00 127.46 0.42 1:40 2.7 0.41 0.22 0.10 0.314 0.478 143.39 0.00 0.00 0.00 0.00 0.00 143.39 0.00 0.00 0.00 0.00 143.39 0.48 1:45 3.3 0.50 0.22 0.12 0.383 0.584 175.26 0.00 0.00 0.00 0.00 0.00 175.26 0.00 0.00 0.00 0.00 175.26 0.58 1:50 3.1 0.47 0.22 0.11 0.360 0.549 164.63 0.00 0.00 0.00 0.00 0.00 164.63 0.00 0.00 0.00 0.00 164.63 0.55 1:55 2.9 0.44 0.22 0.11 0.337 0.513 154.01 0.00 0.00 0.00 0.00 0.00 154.01 0.00 0.00 0.00 0.00 154.01 0.51 2:00 3.0 0.46 0.22 0.11 0.349 0.531 159.32 0.00 0.00 0.00 0.00 0.00 159.32 0.00 0.00 0.00 0.00 159.32 0.53 2:05 3.1 0.47 0.22 0.11 0.360 0.549 164.63 0.00 0.00 0.00 0.00 0.00 164.63 0.00 0.00 0.00 0.00 164.63 0.55 2:10 4.2 0.64 0.22 0.15 0.488 0.744 223.05 0.00 0.00 0.00 0.00 0.00 223.05 0.00 0.00 0.00 0.00 223.05 0.74 2:15 5.0 0.76 0.22 0.18 0.581 0.885 265.54 0.00 0.00 0.00 0.00 0.00 265.54 0.00 0.00 0.00 0.00 265.54 0.89 2:20 3.5 0.53 0.22 0.13 0.407 0.620 185.88 0.00 0.00 0.00 0.00 0.00 185.88 0.00 0.00 0.00 0.00 185.88 0.62 2:25 6.8 1.04 0.22 N/A 0.817 1.245 373.52 0.00 0.00 0.00 0.00 0.00 373.52 0.00 0.00 0.00 0.00 373.52 1.25 2:30 7.3 1.11 0.22 N/A 0.893 1.361 408.35 0.00 0.00 0.00 0.00 0.00 408.35 0.00 0.00 0.00 0.00 408.35 1.36 2:35 8.2 1.25 0.22 N/A 1.031 1.570 471.04 0.00 0.00 0.00 0.00 0.00 471.04 0.00 0.00 0.00 0.00 471.04 1.57 2:40 5.9 0.90 0.22 0.21 0.686 1.044 313.34 0.00 0.00 0.00 0.00 0.00 313.34 0.00 0.00 0.00 0.00 313.34 1.04 2:45 2.0 0.30 0.22 0.07 0.232 0.354 106.22 0.00 0.00 0.00 0.00 0.00 106.22 0.00 0.00 0.00 0.00 106.22 0.35 2:50 1.8 0.27 0.22 0.07 0.209 0.319 95.59 0.00 0.00 0.00 0.00 0.00 95.59 0.00 0.00 0.00 0.00 95.59 0.32 2:55 1.8 0.27 0.22 0.07 0.209 0.319 95.59 0.00 0.00 0.00 0.00 0.00 95.59 0.00 0.00 0.00 0.00 95.59 0.32 3:00 0.6 0.09 0.22 0.02 0.070 0.106 31.86 0.00 0.00 0.00 0.00 0.00 31.86 0.00 0.00 0.00 0.00 31.86 0.11 Total volume (CF)5379.37 Total Overflow (CF)5379.37
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5 -year 6 Hour Storm in 5 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:05 0.5 0.11 0.22 0.03 0.083 0.126 37.84 0.00 0.00 0.00 0.00 0.00 37.84 0.00 0.00 0.00 0.00 37.84 0.13 0:10 0.6 0.13 0.22 0.03 0.099 0.151 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.15 0:15 0.6 0.13 0.22 0.03 0.099 0.151 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.15 0:20 0.6 0.13 0.22 0.03 0.099 0.151 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.15 0:25 0.6 0.13 0.22 0.03 0.099 0.151 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.15 0:30 0.7 0.15 0.22 0.04 0.116 0.177 52.98 0.00 0.00 0.00 0.00 0.00 52.98 0.00 0.00 0.00 0.00 52.98 0.18 0:35 0.7 0.15 0.22 0.04 0.116 0.177 52.98 0.00 0.00 0.00 0.00 0.00 52.98 0.00 0.00 0.00 0.00 52.98 0.18 0:40 0.7 0.15 0.22 0.04 0.116 0.177 52.98 0.00 0.00 0.00 0.00 0.00 52.98 0.00 0.00 0.00 0.00 52.98 0.18 0:45 0.7 0.15 0.22 0.04 0.116 0.177 52.98 0.00 0.00 0.00 0.00 0.00 52.98 0.00 0.00 0.00 0.00 52.98 0.18 0:50 0.7 0.15 0.22 0.04 0.116 0.177 52.98 0.00 0.00 0.00 0.00 0.00 52.98 0.00 0.00 0.00 0.00 52.98 0.18 0:55 0.7 0.15 0.22 0.04 0.116 0.177 52.98 0.00 0.00 0.00 0.00 0.00 52.98 0.00 0.00 0.00 0.00 52.98 0.18 1:00 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 1:05 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 1:10 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 1:15 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 1:20 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 1:25 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 1:30 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 1:35 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 1:40 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 1:45 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 1:50 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 1:55 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 2:00 0.9 0.20 0.22 0.05 0.149 0.227 68.12 0.00 0.00 0.00 0.00 0.00 68.12 0.00 0.00 0.00 0.00 68.12 0.23 2:05 0.8 0.17 0.22 0.04 0.132 0.202 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.20 2:10 0.9 0.20 0.22 0.05 0.149 0.227 68.12 0.00 0.00 0.00 0.00 0.00 68.12 0.00 0.00 0.00 0.00 68.12 0.23 2:15 0.9 0.20 0.22 0.05 0.149 0.227 68.12 0.00 0.00 0.00 0.00 0.00 68.12 0.00 0.00 0.00 0.00 68.12 0.23 2:20 0.9 0.20 0.22 0.05 0.149 0.227 68.12 0.00 0.00 0.00 0.00 0.00 68.12 0.00 0.00 0.00 0.00 68.12 0.23 2:25 0.9 0.20 0.22 0.05 0.149 0.227 68.12 0.00 0.00 0.00 0.00 0.00 68.12 0.00 0.00 0.00 0.00 68.12 0.23 2:30 0.9 0.20 0.22 0.05 0.149 0.227 68.12 0.00 0.00 0.00 0.00 0.00 68.12 0.00 0.00 0.00 0.00 68.12 0.23 2:35 0.9 0.20 0.22 0.05 0.149 0.227 68.12 0.00 0.00 0.00 0.00 0.00 68.12 0.00 0.00 0.00 0.00 68.12 0.23 2:40 0.9 0.20 0.22 0.05 0.149 0.227 68.12 0.00 0.00 0.00 0.00 0.00 68.12 0.00 0.00 0.00 0.00 68.12 0.23 2:45 1.0 0.22 0.22 0.05 0.166 0.252 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.25 2:50 1.0 0.22 0.22 0.05 0.166 0.252 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.25 2:55 1.0 0.22 0.22 0.05 0.166 0.252 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.25 3:00 1.0 0.22 0.22 0.05 0.166 0.252 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.25 3:05 1.0 0.22 0.22 0.05 0.166 0.252 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.25 3:10 1.1 0.24 0.22 0.06 0.182 0.278 83.26 0.00 0.00 0.00 0.00 0.00 83.26 0.00 0.00 0.00 0.00 83.26 0.28 3:15 1.1 0.24 0.22 0.06 0.182 0.278 83.26 0.00 0.00 0.00 0.00 0.00 83.26 0.00 0.00 0.00 0.00 83.26 0.28 3:20 1.1 0.24 0.22 0.06 0.182 0.278 83.26 0.00 0.00 0.00 0.00 0.00 83.26 0.00 0.00 0.00 0.00 83.26 0.28 3:25 1.2 0.26 0.22 0.06 0.199 0.303 90.83 0.00 0.00 0.00 0.00 0.00 90.83 0.00 0.00 0.00 0.00 90.83 0.30 3:30 1.3 0.28 0.22 0.07 0.215 0.328 98.40 0.00 0.00 0.00 0.00 0.00 98.40 0.00 0.00 0.00 0.00 98.40 0.33 3:35 1.4 0.30 0.22 0.07 0.232 0.353 105.96 0.00 0.00 0.00 0.00 0.00 105.96 0.00 0.00 0.00 0.00 105.96 0.35 3:40 1.4 0.30 0.22 0.07 0.232 0.353 105.96 0.00 0.00 0.00 0.00 0.00 105.96 0.00 0.00 0.00 0.00 105.96 0.35 3:45 1.5 0.33 0.22 0.08 0.248 0.378 113.53 0.00 0.00 0.00 0.00 0.00 113.53 0.00 0.00 0.00 0.00 113.53 0.38 3:50 1.5 0.33 0.22 0.08 0.248 0.378 113.53 0.00 0.00 0.00 0.00 0.00 113.53 0.00 0.00 0.00 0.00 113.53 0.38 3:55 1.6 0.35 0.22 0.08 0.265 0.404 121.10 0.00 0.00 0.00 0.00 0.00 121.10 0.00 0.00 0.00 0.00 121.10 0.40 4:00 1.6 0.35 0.22 0.08 0.265 0.404 121.10 0.00 0.00 0.00 0.00 0.00 121.10 0.00 0.00 0.00 0.00 121.10 0.40 4:05 1.7 0.37 0.22 0.09 0.282 0.429 128.67 0.00 0.00 0.00 0.00 0.00 128.67 0.00 0.00 0.00 0.00 128.67 0.43 9 of 24

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4:10 1.8 0.39 0.22 0.09 0.298 0.454 136.24 0.00 0.00 0.00 0.00 0.00 136.24 0.00 0.00 0.00 0.00 136.24 0.45 4:15 1.9 0.41 0.22 0.10 0.315 0.479 143.81 0.00 0.00 0.00 0.00 0.00 143.81 0.00 0.00 0.00 0.00 143.81 0.48 4:20 2.0 0.43 0.22 0.10 0.331 0.505 151.38 0.00 0.00 0.00 0.00 0.00 151.38 0.00 0.00 0.00 0.00 151.38 0.50 4:25 2.1 0.46 0.22 0.11 0.348 0.530 158.95 0.00 0.00 0.00 0.00 0.00 158.95 0.00 0.00 0.00 0.00 158.95 0.53 4:30 2.1 0.46 0.22 0.11 0.348 0.530 158.95 0.00 0.00 0.00 0.00 0.00 158.95 0.00 0.00 0.00 0.00 158.95 0.53 4:35 2.2 0.48 0.22 0.11 0.364 0.555 166.52 0.00 0.00 0.00 0.00 0.00 166.52 0.00 0.00 0.00 0.00 166.52 0.56 4:40 2.3 0.50 0.22 0.12 0.381 0.580 174.08 0.00 0.00 0.00 0.00 0.00 174.08 0.00 0.00 0.00 0.00 174.08 0.58 4:45 2.4 0.52 0.22 0.12 0.397 0.606 181.65 0.00 0.00 0.00 0.00 0.00 181.65 0.00 0.00 0.00 0.00 181.65 0.61 4:50 2.4 0.52 0.22 0.12 0.397 0.606 181.65 0.00 0.00 0.00 0.00 0.00 181.65 0.00 0.00 0.00 0.00 181.65 0.61 4:55 2.5 0.54 0.22 0.13 0.414 0.631 189.22 0.00 0.00 0.00 0.00 0.00 189.22 0.00 0.00 0.00 0.00 189.22 0.63 5:00 2.6 0.56 0.22 0.13 0.431 0.656 196.79 0.00 0.00 0.00 0.00 0.00 196.79 0.00 0.00 0.00 0.00 196.79 0.66 5:05 3.1 0.67 0.22 0.16 0.513 0.782 234.64 0.00 0.00 0.00 0.00 0.00 234.64 0.00 0.00 0.00 0.00 234.64 0.78 5:10 3.6 0.78 0.22 0.19 0.596 0.908 272.48 0.00 0.00 0.00 0.00 0.00 272.48 0.00 0.00 0.00 0.00 272.48 0.91 5:15 3.9 0.85 0.22 0.20 0.646 0.984 295.19 0.00 0.00 0.00 0.00 0.00 295.19 0.00 0.00 0.00 0.00 295.19 0.98 5:20 4.2 0.91 0.22 0.22 0.695 1.060 317.89 0.00 0.00 0.00 0.00 0.00 317.89 0.00 0.00 0.00 0.00 317.89 1.06 5:25 4.7 1.02 0.22 N/A 0.802 1.221 366.44 0.00 0.00 0.00 0.00 0.00 366.44 0.00 0.00 0.00 0.00 366.44 1.22 5:30 5.6 1.22 0.22 N/A 0.997 1.519 455.79 0.00 0.00 0.00 0.00 0.00 455.79 0.00 0.00 0.00 0.00 455.79 1.52 5:35 1.9 0.41 0.22 0.10 0.315 0.479 143.81 0.00 0.00 0.00 0.00 0.00 143.81 0.00 0.00 0.00 0.00 143.81 0.48 5:40 0.9 0.20 0.22 0.05 0.149 0.227 68.12 0.00 0.00 0.00 0.00 0.00 68.12 0.00 0.00 0.00 0.00 68.12 0.23 5:45 0.6 0.13 0.22 0.03 0.099 0.151 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.15 5:50 0.5 0.11 0.22 0.03 0.083 0.126 37.84 0.00 0.00 0.00 0.00 0.00 37.84 0.00 0.00 0.00 0.00 37.84 0.13 5:55 0.3 0.07 0.22 0.02 0.050 0.076 22.71 0.00 0.00 0.00 0.00 0.00 22.71 0.00 0.00 0.00 0.00 22.71 0.08 6:00 0.2 0.04 0.22 0.01 0.033 0.050 15.14 0.00 0.00 0.00 0.00 0.00 15.14 0.00 0.00 0.00 0.00 15.14 0.05 Total volume (CF)7611.52 Total Overflow (CF)7611.52
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5 -year 24 Hour Storm in 15 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:15 0.2 0.03 0.38 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 0:30 0.3 0.04 0.38 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 0:45 0.3 0.04 0.38 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 1:00 0.4 0.06 0.37 0.01 0.044 0.067 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.07 1:15 0.3 0.04 0.37 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 1:30 0.3 0.04 0.36 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 1:45 0.3 0.04 0.36 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 2:00 0.4 0.06 0.35 0.01 0.044 0.067 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.07 2:15 0.4 0.06 0.35 0.01 0.044 0.067 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.07 2:30 0.4 0.06 0.35 0.01 0.044 0.067 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.07 2:45 0.5 0.07 0.34 0.02 0.055 0.084 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.08 3:00 0.5 0.07 0.34 0.02 0.055 0.084 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.08 3:15 0.5 0.07 0.33 0.02 0.055 0.084 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.08 3:30 0.5 0.07 0.33 0.02 0.055 0.084 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.08 3:45 0.5 0.07 0.32 0.02 0.055 0.084 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.08 4:00 0.6 0.09 0.32 0.02 0.066 0.101 90.83 0.00 0.00 0.00 0.00 0.00 90.83 0.00 0.00 0.00 0.00 90.83 0.10 4:15 0.6 0.09 0.32 0.02 0.066 0.101 90.83 0.00 0.00 0.00 0.00 0.00 90.83 0.00 0.00 0.00 0.00 90.83 0.10 4:30 0.7 0.10 0.31 0.02 0.077 0.118 105.96 0.00 0.00 0.00 0.00 0.00 105.96 0.00 0.00 0.00 0.00 105.96 0.12 4:45 0.7 0.10 0.31 0.02 0.077 0.118 105.96 0.00 0.00 0.00 0.00 0.00 105.96 0.00 0.00 0.00 0.00 105.96 0.12 5:00 0.8 0.12 0.30 0.03 0.088 0.135 121.10 0.00 0.00 0.00 0.00 0.00 121.10 0.00 0.00 0.00 0.00 121.10 0.13 5:15 0.6 0.09 0.30 0.02 0.066 0.101 90.83 0.00 0.00 0.00 0.00 0.00 90.83 0.00 0.00 0.00 0.00 90.83 0.10 5:30 0.7 0.10 0.30 0.02 0.077 0.118 105.96 0.00 0.00 0.00 0.00 0.00 105.96 0.00 0.00 0.00 0.00 105.96 0.12 5:45 0.8 0.12 0.29 0.03 0.088 0.135 121.10 0.00 0.00 0.00 0.00 0.00 121.10 0.00 0.00 0.00 0.00 121.10 0.13 6:00 0.8 0.12 0.29 0.03 0.088 0.135 121.10 0.00 0.00 0.00 0.00 0.00 121.10 0.00 0.00 0.00 0.00 121.10 0.13 6:15 0.9 0.13 0.28 0.03 0.099 0.151 136.24 0.00 0.00 0.00 0.00 0.00 136.24 0.00 0.00 0.00 0.00 136.24 0.15 6:30 0.9 0.13 0.28 0.03 0.099 0.151 136.24 0.00 0.00 0.00 0.00 0.00 136.24 0.00 0.00 0.00 0.00 136.24 0.15 6:45 1.0 0.14 0.28 0.03 0.110 0.168 151.38 0.00 0.00 0.00 0.00 0.00 151.38 0.00 0.00 0.00 0.00 151.38 0.17 7:00 1.0 0.14 0.27 0.03 0.110 0.168 151.38 0.00 0.00 0.00 0.00 0.00 151.38 0.00 0.00 0.00 0.00 151.38 0.17 7:15 1.0 0.14 0.27 0.03 0.110 0.168 151.38 0.00 0.00 0.00 0.00 0.00 151.38 0.00 0.00 0.00 0.00 151.38 0.17 7:30 1.1 0.16 0.27 0.04 0.121 0.185 166.52 0.00 0.00 0.00 0.00 0.00 166.52 0.00 0.00 0.00 0.00 166.52 0.19 7:45 1.2 0.17 0.26 0.04 0.132 0.202 181.65 0.00 0.00 0.00 0.00 0.00 181.65 0.00 0.00 0.00 0.00 181.65 0.20 8:00 1.3 0.19 0.26 0.04 0.144 0.219 196.79 0.00 0.00 0.00 0.00 0.00 196.79 0.00 0.00 0.00 0.00 196.79 0.22 8:15 1.5 0.22 0.26 0.05 0.166 0.252 227.07 0.00 0.00 0.00 0.00 0.00 227.07 0.00 0.00 0.00 0.00 227.07 0.25 8:30 1.5 0.22 0.25 0.05 0.166 0.252 227.07 0.00 0.00 0.00 0.00 0.00 227.07 0.00 0.00 0.00 0.00 227.07 0.25 8:45 1.6 0.23 0.25 0.06 0.177 0.269 242.20 0.00 0.00 0.00 0.00 0.00 242.20 0.00 0.00 0.00 0.00 242.20 0.27 9:00 1.7 0.25 0.24 0.06 0.188 0.286 257.34 0.00 0.00 0.00 0.00 0.00 257.34 0.00 0.00 0.00 0.00 257.34 0.29 9:15 1.9 0.28 0.24 0.07 0.210 0.320 287.62 0.00 0.00 0.00 0.00 0.00 287.62 0.00 0.00 0.00 0.00 287.62 0.32 9:30 2.0 0.29 0.24 0.07 0.221 0.336 302.76 0.00 0.00 0.00 0.00 0.00 302.76 0.00 0.00 0.00 0.00 302.76 0.34 9:45 2.1 0.30 0.23 0.07 0.232 0.353 317.89 0.00 0.00 0.00 0.00 0.00 317.89 0.00 0.00 0.00 0.00 317.89 0.35 10:00 2.2 0.32 0.23 0.08 0.243 0.370 333.03 0.00 0.00 0.00 0.00 0.00 333.03 0.00 0.00 0.00 0.00 333.03 0.37 10:15 1.5 0.22 0.23 0.05 0.166 0.252 227.07 0.00 0.00 0.00 0.00 0.00 227.07 0.00 0.00 0.00 0.00 227.07 0.25 10:30 1.5 0.22 0.22 0.05 0.166 0.252 227.07 0.00 0.00 0.00 0.00 0.00 227.07 0.00 0.00 0.00 0.00 227.07 0.25 10:45 2.0 0.29 0.22 0.07 0.221 0.336 302.76 0.00 0.00 0.00 0.00 0.00 302.76 0.00 0.00 0.00 0.00 302.76 0.34 11:00 2.0 0.29 0.22 0.07 0.221 0.336 302.76 0.00 0.00 0.00 0.00 0.00 302.76 0.00 0.00 0.00 0.00 302.76 0.34 11:15 1.9 0.28 0.21 0.07 0.210 0.320 287.62 0.00 0.00 0.00 0.00 0.00 287.62 0.00 0.00 0.00 0.00 287.62 0.32 11:30 1.9 0.28 0.21 0.07 0.210 0.320 287.62 0.00 0.00 0.00 0.00 0.00 287.62 0.00 0.00 0.00 0.00 287.62 0.32 11:45 1.7 0.25 0.21 0.06 0.188 0.286 257.34 0.00 0.00 0.00 0.00 0.00 257.34 0.00 0.00 0.00 0.00 257.34 0.29 12:00 1.8 0.26 0.21 0.06 0.199 0.303 272.48 0.00 0.00 0.00 0.00 0.00 272.48 0.00 0.00 0.00 0.00 272.48 0.30 12:15 2.5 0.36 0.20 0.09 0.276 0.420 378.44 0.00 0.00 0.00 0.00 0.00 378.44 0.00 0.00 0.00 0.00 378.44 0.42 11 of 24

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12:30 2.6 0.38 0.20 0.09 0.287 0.437 393.58 0.00 0.00 0.00 0.00 0.00 393.58 0.00 0.00 0.00 0.00 393.58 0.44 12:45 2.8 0.41 0.20 0.10 0.309 0.471 423.86 0.00 0.00 0.00 0.00 0.00 423.86 0.00 0.00 0.00 0.00 423.86 0.47 13:00 2.9 0.42 0.19 0.10 0.320 0.488 439.00 0.00 0.00 0.00 0.00 0.00 439.00 0.00 0.00 0.00 0.00 439.00 0.49 13:15 3.4 0.49 0.19 0.12 0.375 0.572 514.68 0.00 0.00 0.00 0.00 0.00 514.68 0.00 0.00 0.00 0.00 514.68 0.57 13:30 3.4 0.49 0.19 0.12 0.375 0.572 514.68 0.00 0.00 0.00 0.00 0.00 514.68 0.00 0.00 0.00 0.00 514.68 0.57 13:45 2.3 0.33 0.18 0.08 0.254 0.387 348.17 0.00 0.00 0.00 0.00 0.00 348.17 0.00 0.00 0.00 0.00 348.17 0.39 14:00 2.3 0.33 0.18 0.08 0.254 0.387 348.17 0.00 0.00 0.00 0.00 0.00 348.17 0.00 0.00 0.00 0.00 348.17 0.39 14:15 2.7 0.39 0.18 0.09 0.298 0.454 408.72 0.00 0.00 0.00 0.00 0.00 408.72 0.00 0.00 0.00 0.00 408.72 0.45 14:30 2.6 0.38 0.18 0.09 0.287 0.437 393.58 0.00 0.00 0.00 0.00 0.00 393.58 0.00 0.00 0.00 0.00 393.58 0.44 14:45 2.6 0.38 0.17 0.09 0.287 0.437 393.58 0.00 0.00 0.00 0.00 0.00 393.58 0.00 0.00 0.00 0.00 393.58 0.44 15:00 2.5 0.36 0.17 0.09 0.276 0.420 378.44 0.00 0.00 0.00 0.00 0.00 378.44 0.00 0.00 0.00 0.00 378.44 0.42 15:15 2.4 0.35 0.17 0.08 0.265 0.404 363.31 0.00 0.00 0.00 0.00 0.00 363.31 0.00 0.00 0.00 0.00 363.31 0.40 15:30 2.3 0.33 0.17 0.08 0.254 0.387 348.17 0.00 0.00 0.00 0.00 0.00 348.17 0.00 0.00 0.00 0.00 348.17 0.39 15:45 1.9 0.28 0.16 0.07 0.210 0.320 287.62 0.00 0.00 0.00 0.00 0.00 287.62 0.00 0.00 0.00 0.00 287.62 0.32 16:00 1.9 0.28 0.16 0.07 0.210 0.320 287.62 0.00 0.00 0.00 0.00 0.00 287.62 0.00 0.00 0.00 0.00 287.62 0.32 16:15 0.4 0.06 0.16 0.01 0.044 0.067 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.07 16:30 0.4 0.06 0.16 0.01 0.044 0.067 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.07 16:45 0.3 0.04 0.15 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 17:00 0.3 0.04 0.15 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 17:15 0.5 0.07 0.15 0.02 0.055 0.084 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.08 17:30 0.5 0.07 0.15 0.02 0.055 0.084 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.08 17:45 0.5 0.07 0.14 0.02 0.055 0.084 75.69 0.00 0.00 0.00 0.00 0.00 75.69 0.00 0.00 0.00 0.00 75.69 0.08 18:00 0.4 0.06 0.14 0.01 0.044 0.067 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.07 18:15 0.4 0.06 0.14 0.01 0.044 0.067 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.07 18:30 0.4 0.06 0.14 0.01 0.044 0.067 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.07 18:45 0.3 0.04 0.14 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 19:00 0.2 0.03 0.13 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 19:15 0.3 0.04 0.13 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 19:30 0.4 0.06 0.13 0.01 0.044 0.067 60.55 0.00 0.00 0.00 0.00 0.00 60.55 0.00 0.00 0.00 0.00 60.55 0.07 19:45 0.3 0.04 0.13 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 20:00 0.2 0.03 0.13 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 20:15 0.3 0.04 0.13 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 20:30 0.3 0.04 0.12 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 20:45 0.3 0.04 0.12 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 21:00 0.2 0.03 0.12 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 21:15 0.3 0.04 0.12 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 21:30 0.2 0.03 0.12 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 21:45 0.3 0.04 0.12 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 22:00 0.2 0.03 0.12 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 22:15 0.3 0.04 0.11 0.01 0.033 0.050 45.41 0.00 0.00 0.00 0.00 0.00 45.41 0.00 0.00 0.00 0.00 45.41 0.05 22:30 0.2 0.03 0.11 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 22:45 0.2 0.03 0.11 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 23:00 0.2 0.03 0.11 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 23:15 0.2 0.03 0.11 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 23:30 0.2 0.03 0.11 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 23:45 0.2 0.03 0.11 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 24:00 0.2 0.03 0.11 0.01 0.022 0.034 30.28 0.00 0.00 0.00 0.00 0.00 30.28 0.00 0.00 0.00 0.00 30.28 0.03 Total volume (CF)15137.76 Total Overflow (CF)15137.76
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Project:Beaumont Post-Development
Recurrence Interval 10 year
Storm Duration (hrs)1 3 6 24
10-year NOAA Atlas 14 Point Precipitation (in)1.010 1.520 2.130 4.310 Unit time (minutes)5 5 5 15
Drainage Area 65819 SF 1.511 Ac.

Soils Group B
AMC index Runoff Number (plate E-6.1)65 Type:Urban Covers; good Pervious Area Loss Rate (Fp)(in/hr) (plate E-6.2)0.51 AMC II Percentage of Impervious Cover (Ai)(%) (plate E-6.3)83
Weighted Average Loss Rate (F=Fp(1-.9Ai))(in./hr.)0.13 (used for 1, 3, and 6 hour storm, the 24 hour storm uses variable maximum loss rate per plate E-1.1 (3 of 6)) Low Loss Rate Percent (%) 24
Percolation Rate (in/hr)1.00 (Used for retention basin and drywell) Percolation is taken incrementally.

Basin volume is calculated using the "truncated pyramid" formula, a more conservative estimate than "averaged end areas" sometimes used (Drywell can be "zeroed out" by reducing numbers to less than .001, but should not entered as zeros or program chokes.) Drywell storage includes 40% of the 1' wide rock bed surrounding the drywell: formula (upper)*PI()*(diam/2)^2+(lower)*PI()*((diam/2)^2+0.4*((diam/2+(grav+0.4166))^2-(diam/2+0.4166)^2)) The drywell wall thickness is assumed at 5" (0.4166) and the gravel bed width is variable "grav" Drywell design factors
Upper sec. (FT)=0.0001 Lower sec. (FT)=0.0001 Ring diam. (FT) =0.0001 Gravel bed width around drywell=0.0001 Drywell lower max. (CF)=0.00 Upper max.(CF)=0.00 Drywell total(CF)=0.00 Retention Basin design factors
Top (SF)=0.0001 Bot. (SF)=0.0001 Max. Depth (FT)=0.0001 Max. storage (CF)=0.00 (d/3)*(bottom+top+(bottom*top)^0.50) Formulas vol=(h/3)*(bottom+top+(bottom*top)^0.50) area=bottom+(h/d)*(top-bottom)h=(vol*3)/(bottom+top+(bottom*top)^0.5) 10 -year 1 Hour Storm in 5 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:05 3.7 0.45 0.13 0.11 0.342 0.521 156.27 0.00 0.00 0.00 0.00 0.00 156.27 0.00 0.00 0.00 0.00 156.27 0.52 0:10 4.8 0.58 0.13 N/A 0.452 0.688 206.51 0.00 0.00 0.00 0.00 0.00 206.51 0.00 0.00 0.00 0.00 206.51 0.69 0:15 5.1 0.62 0.13 N/A 0.488 0.744 223.13 0.00 0.00 0.00 0.00 0.00 223.13 0.00 0.00 0.00 0.00 223.13 0.74 0:20 4.9 0.59 0.13 N/A 0.464 0.707 212.05 0.00 0.00 0.00 0.00 0.00 212.05 0.00 0.00 0.00 0.00 212.05 0.71 0:25 6.6 0.80 0.13 N/A 0.670 1.021 306.23 0.00 0.00 0.00 0.00 0.00 306.23 0.00 0.00 0.00 0.00 306.23 1.02 0:30 7.3 0.88 0.13 N/A 0.755 1.150 345.01 0.00 0.00 0.00 0.00 0.00 345.01 0.00 0.00 0.00 0.00 345.01 1.15 0:35 8.4 1.02 0.13 N/A 0.888 1.353 405.94 0.00 0.00 0.00 0.00 0.00 405.94 0.00 0.00 0.00 0.00 405.94 1.35 0:40 9.0 1.09 0.13 N/A 0.961 1.464 439.18 0.00 0.00 0.00 0.00 0.00 439.18 0.00 0.00 0.00 0.00 439.18 1.46 0:45 12.3 1.49 0.13 N/A 1.361 2.073 622.00 0.00 0.00 0.00 0.00 0.00 622.00 0.00 0.00 0.00 0.00 622.00 2.07 0:50 17.6 2.13 0.13 N/A 2.003 3.052 915.60 0.00 0.00 0.00 0.00 0.00 915.60 0.00 0.00 0.00 0.00 915.60 3.05 0:55 16.1 1.95 0.13 N/A 1.821 2.775 832.51 0.00 0.00 0.00 0.00 0.00 832.51 0.00 0.00 0.00 0.00 832.51 2.78 1:00 4.2 0.51 0.13 0.12 0.388 0.591 177.39 0.00 0.00 0.00 0.00 0.00 177.39 0.00 0.00 0.00 0.00 177.39 0.59 Total volume (CF)4841.82 Total Overflow (CF)4841.82
RCFC&WCD Short Cut Unit Hydrograph Method
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10 -year 3 Hour Storm in 5 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:05 1.3 0.24 0.13 0.06 0.181 0.275 82.63 0.00 0.00 0.00 0.00 0.00 82.63 0.00 0.00 0.00 0.00 82.63 0.28 0:10 1.3 0.24 0.13 0.06 0.181 0.275 82.63 0.00 0.00 0.00 0.00 0.00 82.63 0.00 0.00 0.00 0.00 82.63 0.28 0:15 1.1 0.20 0.13 0.05 0.153 0.233 69.92 0.00 0.00 0.00 0.00 0.00 69.92 0.00 0.00 0.00 0.00 69.92 0.23 0:20 1.5 0.27 0.13 0.07 0.209 0.318 95.34 0.00 0.00 0.00 0.00 0.00 95.34 0.00 0.00 0.00 0.00 95.34 0.32 0:25 1.5 0.27 0.13 0.07 0.209 0.318 95.34 0.00 0.00 0.00 0.00 0.00 95.34 0.00 0.00 0.00 0.00 95.34 0.32 0:30 1.8 0.33 0.13 0.08 0.250 0.381 114.41 0.00 0.00 0.00 0.00 0.00 114.41 0.00 0.00 0.00 0.00 114.41 0.38 0:35 1.5 0.27 0.13 0.07 0.209 0.318 95.34 0.00 0.00 0.00 0.00 0.00 95.34 0.00 0.00 0.00 0.00 95.34 0.32 0:40 1.8 0.33 0.13 0.08 0.250 0.381 114.41 0.00 0.00 0.00 0.00 0.00 114.41 0.00 0.00 0.00 0.00 114.41 0.38 0:45 1.8 0.33 0.13 0.08 0.250 0.381 114.41 0.00 0.00 0.00 0.00 0.00 114.41 0.00 0.00 0.00 0.00 114.41 0.38 0:50 1.5 0.27 0.13 0.07 0.209 0.318 95.34 0.00 0.00 0.00 0.00 0.00 95.34 0.00 0.00 0.00 0.00 95.34 0.32 0:55 1.6 0.29 0.13 0.07 0.222 0.339 101.70 0.00 0.00 0.00 0.00 0.00 101.70 0.00 0.00 0.00 0.00 101.70 0.34 1:00 1.8 0.33 0.13 0.08 0.250 0.381 114.41 0.00 0.00 0.00 0.00 0.00 114.41 0.00 0.00 0.00 0.00 114.41 0.38 1:05 2.2 0.40 0.13 0.10 0.306 0.466 139.84 0.00 0.00 0.00 0.00 0.00 139.84 0.00 0.00 0.00 0.00 139.84 0.47 1:10 2.2 0.40 0.13 0.10 0.306 0.466 139.84 0.00 0.00 0.00 0.00 0.00 139.84 0.00 0.00 0.00 0.00 139.84 0.47 1:15 2.2 0.40 0.13 0.10 0.306 0.466 139.84 0.00 0.00 0.00 0.00 0.00 139.84 0.00 0.00 0.00 0.00 139.84 0.47 1:20 2.0 0.36 0.13 0.09 0.278 0.424 127.12 0.00 0.00 0.00 0.00 0.00 127.12 0.00 0.00 0.00 0.00 127.12 0.42 1:25 2.6 0.47 0.13 0.11 0.362 0.551 165.26 0.00 0.00 0.00 0.00 0.00 165.26 0.00 0.00 0.00 0.00 165.26 0.55 1:30 2.7 0.49 0.13 0.12 0.375 0.572 171.62 0.00 0.00 0.00 0.00 0.00 171.62 0.00 0.00 0.00 0.00 171.62 0.57 1:35 2.4 0.44 0.13 0.10 0.334 0.508 152.55 0.00 0.00 0.00 0.00 0.00 152.55 0.00 0.00 0.00 0.00 152.55 0.51 1:40 2.7 0.49 0.13 0.12 0.375 0.572 171.62 0.00 0.00 0.00 0.00 0.00 171.62 0.00 0.00 0.00 0.00 171.62 0.57 1:45 3.3 0.60 0.13 N/A 0.472 0.719 215.73 0.00 0.00 0.00 0.00 0.00 215.73 0.00 0.00 0.00 0.00 215.73 0.72 1:50 3.1 0.57 0.13 N/A 0.435 0.664 199.05 0.00 0.00 0.00 0.00 0.00 199.05 0.00 0.00 0.00 0.00 199.05 0.66 1:55 2.9 0.53 0.13 0.13 0.403 0.614 184.33 0.00 0.00 0.00 0.00 0.00 184.33 0.00 0.00 0.00 0.00 184.33 0.61 2:00 3.0 0.55 0.13 N/A 0.417 0.636 190.72 0.00 0.00 0.00 0.00 0.00 190.72 0.00 0.00 0.00 0.00 190.72 0.64 2:05 3.1 0.57 0.13 N/A 0.435 0.664 199.05 0.00 0.00 0.00 0.00 0.00 199.05 0.00 0.00 0.00 0.00 199.05 0.66 2:10 4.2 0.77 0.13 N/A 0.636 0.969 290.76 0.00 0.00 0.00 0.00 0.00 290.76 0.00 0.00 0.00 0.00 290.76 0.97 2:15 5.0 0.91 0.13 N/A 0.782 1.192 357.46 0.00 0.00 0.00 0.00 0.00 357.46 0.00 0.00 0.00 0.00 357.46 1.19 2:20 3.5 0.64 0.13 N/A 0.508 0.775 232.40 0.00 0.00 0.00 0.00 0.00 232.40 0.00 0.00 0.00 0.00 232.40 0.77 2:25 6.8 1.24 0.13 N/A 1.110 1.692 507.53 0.00 0.00 0.00 0.00 0.00 507.53 0.00 0.00 0.00 0.00 507.53 1.69 2:30 7.3 1.33 0.13 N/A 1.202 1.831 549.21 0.00 0.00 0.00 0.00 0.00 549.21 0.00 0.00 0.00 0.00 549.21 1.83 2:35 8.2 1.50 0.13 N/A 1.366 2.081 624.24 0.00 0.00 0.00 0.00 0.00 624.24 0.00 0.00 0.00 0.00 624.24 2.08 2:40 5.9 1.08 0.13 N/A 0.946 1.442 432.49 0.00 0.00 0.00 0.00 0.00 432.49 0.00 0.00 0.00 0.00 432.49 1.44 2:45 2.0 0.36 0.13 0.09 0.278 0.424 127.12 0.00 0.00 0.00 0.00 0.00 127.12 0.00 0.00 0.00 0.00 127.12 0.42 2:50 1.8 0.33 0.13 0.08 0.250 0.381 114.41 0.00 0.00 0.00 0.00 0.00 114.41 0.00 0.00 0.00 0.00 114.41 0.38 2:55 1.8 0.33 0.13 0.08 0.250 0.381 114.41 0.00 0.00 0.00 0.00 0.00 114.41 0.00 0.00 0.00 0.00 114.41 0.38 3:00 0.6 0.11 0.13 0.03 0.083 0.127 38.14 0.00 0.00 0.00 0.00 0.00 38.14 0.00 0.00 0.00 0.00 38.14 0.13 Total volume (CF)6760.63 Total Overflow (CF)6760.63
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10 -year 6 Hour Storm in 5 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:05 0.5 0.13 0.13 0.03 0.097 0.148 44.54 0.00 0.00 0.00 0.00 0.00 44.54 0.00 0.00 0.00 0.00 44.54 0.15 0:10 0.6 0.15 0.13 0.04 0.117 0.178 53.44 0.00 0.00 0.00 0.00 0.00 53.44 0.00 0.00 0.00 0.00 53.44 0.18 0:15 0.6 0.15 0.13 0.04 0.117 0.178 53.44 0.00 0.00 0.00 0.00 0.00 53.44 0.00 0.00 0.00 0.00 53.44 0.18 0:20 0.6 0.15 0.13 0.04 0.117 0.178 53.44 0.00 0.00 0.00 0.00 0.00 53.44 0.00 0.00 0.00 0.00 53.44 0.18 0:25 0.6 0.15 0.13 0.04 0.117 0.178 53.44 0.00 0.00 0.00 0.00 0.00 53.44 0.00 0.00 0.00 0.00 53.44 0.18 0:30 0.7 0.18 0.13 0.04 0.136 0.208 62.35 0.00 0.00 0.00 0.00 0.00 62.35 0.00 0.00 0.00 0.00 62.35 0.21 0:35 0.7 0.18 0.13 0.04 0.136 0.208 62.35 0.00 0.00 0.00 0.00 0.00 62.35 0.00 0.00 0.00 0.00 62.35 0.21 0:40 0.7 0.18 0.13 0.04 0.136 0.208 62.35 0.00 0.00 0.00 0.00 0.00 62.35 0.00 0.00 0.00 0.00 62.35 0.21 0:45 0.7 0.18 0.13 0.04 0.136 0.208 62.35 0.00 0.00 0.00 0.00 0.00 62.35 0.00 0.00 0.00 0.00 62.35 0.21 0:50 0.7 0.18 0.13 0.04 0.136 0.208 62.35 0.00 0.00 0.00 0.00 0.00 62.35 0.00 0.00 0.00 0.00 62.35 0.21 0:55 0.7 0.18 0.13 0.04 0.136 0.208 62.35 0.00 0.00 0.00 0.00 0.00 62.35 0.00 0.00 0.00 0.00 62.35 0.21 1:00 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 1:05 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 1:10 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 1:15 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 1:20 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 1:25 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 1:30 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 1:35 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 1:40 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 1:45 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 1:50 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 1:55 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 2:00 0.9 0.23 0.13 0.05 0.175 0.267 80.16 0.00 0.00 0.00 0.00 0.00 80.16 0.00 0.00 0.00 0.00 80.16 0.27 2:05 0.8 0.20 0.13 0.05 0.156 0.238 71.26 0.00 0.00 0.00 0.00 0.00 71.26 0.00 0.00 0.00 0.00 71.26 0.24 2:10 0.9 0.23 0.13 0.05 0.175 0.267 80.16 0.00 0.00 0.00 0.00 0.00 80.16 0.00 0.00 0.00 0.00 80.16 0.27 2:15 0.9 0.23 0.13 0.05 0.175 0.267 80.16 0.00 0.00 0.00 0.00 0.00 80.16 0.00 0.00 0.00 0.00 80.16 0.27 2:20 0.9 0.23 0.13 0.05 0.175 0.267 80.16 0.00 0.00 0.00 0.00 0.00 80.16 0.00 0.00 0.00 0.00 80.16 0.27 2:25 0.9 0.23 0.13 0.05 0.175 0.267 80.16 0.00 0.00 0.00 0.00 0.00 80.16 0.00 0.00 0.00 0.00 80.16 0.27 2:30 0.9 0.23 0.13 0.05 0.175 0.267 80.16 0.00 0.00 0.00 0.00 0.00 80.16 0.00 0.00 0.00 0.00 80.16 0.27 2:35 0.9 0.23 0.13 0.05 0.175 0.267 80.16 0.00 0.00 0.00 0.00 0.00 80.16 0.00 0.00 0.00 0.00 80.16 0.27 2:40 0.9 0.23 0.13 0.05 0.175 0.267 80.16 0.00 0.00 0.00 0.00 0.00 80.16 0.00 0.00 0.00 0.00 80.16 0.27 2:45 1.0 0.26 0.13 0.06 0.195 0.297 89.07 0.00 0.00 0.00 0.00 0.00 89.07 0.00 0.00 0.00 0.00 89.07 0.30 2:50 1.0 0.26 0.13 0.06 0.195 0.297 89.07 0.00 0.00 0.00 0.00 0.00 89.07 0.00 0.00 0.00 0.00 89.07 0.30 2:55 1.0 0.26 0.13 0.06 0.195 0.297 89.07 0.00 0.00 0.00 0.00 0.00 89.07 0.00 0.00 0.00 0.00 89.07 0.30 3:00 1.0 0.26 0.13 0.06 0.195 0.297 89.07 0.00 0.00 0.00 0.00 0.00 89.07 0.00 0.00 0.00 0.00 89.07 0.30 3:05 1.0 0.26 0.13 0.06 0.195 0.297 89.07 0.00 0.00 0.00 0.00 0.00 89.07 0.00 0.00 0.00 0.00 89.07 0.30 3:10 1.1 0.28 0.13 0.07 0.214 0.327 97.98 0.00 0.00 0.00 0.00 0.00 97.98 0.00 0.00 0.00 0.00 97.98 0.33 3:15 1.1 0.28 0.13 0.07 0.214 0.327 97.98 0.00 0.00 0.00 0.00 0.00 97.98 0.00 0.00 0.00 0.00 97.98 0.33 3:20 1.1 0.28 0.13 0.07 0.214 0.327 97.98 0.00 0.00 0.00 0.00 0.00 97.98 0.00 0.00 0.00 0.00 97.98 0.33 3:25 1.2 0.31 0.13 0.07 0.234 0.356 106.88 0.00 0.00 0.00 0.00 0.00 106.88 0.00 0.00 0.00 0.00 106.88 0.36 3:30 1.3 0.33 0.13 0.08 0.253 0.386 115.79 0.00 0.00 0.00 0.00 0.00 115.79 0.00 0.00 0.00 0.00 115.79 0.39 3:35 1.4 0.36 0.13 0.09 0.273 0.416 124.70 0.00 0.00 0.00 0.00 0.00 124.70 0.00 0.00 0.00 0.00 124.70 0.42 3:40 1.4 0.36 0.13 0.09 0.273 0.416 124.70 0.00 0.00 0.00 0.00 0.00 124.70 0.00 0.00 0.00 0.00 124.70 0.42 3:45 1.5 0.38 0.13 0.09 0.292 0.445 133.61 0.00 0.00 0.00 0.00 0.00 133.61 0.00 0.00 0.00 0.00 133.61 0.45 3:50 1.5 0.38 0.13 0.09 0.292 0.445 133.61 0.00 0.00 0.00 0.00 0.00 133.61 0.00 0.00 0.00 0.00 133.61 0.45 3:55 1.6 0.41 0.13 0.10 0.312 0.475 142.51 0.00 0.00 0.00 0.00 0.00 142.51 0.00 0.00 0.00 0.00 142.51 0.48 4:00 1.6 0.41 0.13 0.10 0.312 0.475 142.51 0.00 0.00 0.00 0.00 0.00 142.51 0.00 0.00 0.00 0.00 142.51 0.48 4:05 1.7 0.43 0.13 0.10 0.331 0.505 151.42 0.00 0.00 0.00 0.00 0.00 151.42 0.00 0.00 0.00 0.00 151.42 0.50 15 of 24

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4:10 1.8 0.46 0.13 0.11 0.351 0.534 160.33 0.00 0.00 0.00 0.00 0.00 160.33 0.00 0.00 0.00 0.00 160.33 0.53 4:15 1.9 0.49 0.13 0.12 0.370 0.564 169.23 0.00 0.00 0.00 0.00 0.00 169.23 0.00 0.00 0.00 0.00 169.23 0.56 4:20 2.0 0.51 0.13 0.12 0.390 0.594 178.14 0.00 0.00 0.00 0.00 0.00 178.14 0.00 0.00 0.00 0.00 178.14 0.59 4:25 2.1 0.54 0.13 0.13 0.409 0.623 187.05 0.00 0.00 0.00 0.00 0.00 187.05 0.00 0.00 0.00 0.00 187.05 0.62 4:30 2.1 0.54 0.13 0.13 0.409 0.623 187.05 0.00 0.00 0.00 0.00 0.00 187.05 0.00 0.00 0.00 0.00 187.05 0.62 4:35 2.2 0.56 0.13 N/A 0.432 0.659 197.63 0.00 0.00 0.00 0.00 0.00 197.63 0.00 0.00 0.00 0.00 197.63 0.66 4:40 2.3 0.59 0.13 N/A 0.458 0.698 209.31 0.00 0.00 0.00 0.00 0.00 209.31 0.00 0.00 0.00 0.00 209.31 0.70 4:45 2.4 0.61 0.13 N/A 0.483 0.737 220.99 0.00 0.00 0.00 0.00 0.00 220.99 0.00 0.00 0.00 0.00 220.99 0.74 4:50 2.4 0.61 0.13 N/A 0.483 0.737 220.99 0.00 0.00 0.00 0.00 0.00 220.99 0.00 0.00 0.00 0.00 220.99 0.74 4:55 2.5 0.64 0.13 N/A 0.509 0.776 232.68 0.00 0.00 0.00 0.00 0.00 232.68 0.00 0.00 0.00 0.00 232.68 0.78 5:00 2.6 0.66 0.13 N/A 0.535 0.815 244.36 0.00 0.00 0.00 0.00 0.00 244.36 0.00 0.00 0.00 0.00 244.36 0.81 5:05 3.1 0.79 0.13 N/A 0.662 1.009 302.77 0.00 0.00 0.00 0.00 0.00 302.77 0.00 0.00 0.00 0.00 302.77 1.01 5:10 3.6 0.92 0.13 N/A 0.790 1.204 361.19 0.00 0.00 0.00 0.00 0.00 361.19 0.00 0.00 0.00 0.00 361.19 1.20 5:15 3.9 1.00 0.13 N/A 0.867 1.321 396.24 0.00 0.00 0.00 0.00 0.00 396.24 0.00 0.00 0.00 0.00 396.24 1.32 5:20 4.2 1.07 0.13 N/A 0.944 1.438 431.28 0.00 0.00 0.00 0.00 0.00 431.28 0.00 0.00 0.00 0.00 431.28 1.44 5:25 4.7 1.20 0.13 N/A 1.071 1.632 489.70 0.00 0.00 0.00 0.00 0.00 489.70 0.00 0.00 0.00 0.00 489.70 1.63 5:30 5.6 1.43 0.13 N/A 1.301 1.983 594.85 0.00 0.00 0.00 0.00 0.00 594.85 0.00 0.00 0.00 0.00 594.85 1.98 5:35 1.9 0.49 0.13 0.12 0.370 0.564 169.23 0.00 0.00 0.00 0.00 0.00 169.23 0.00 0.00 0.00 0.00 169.23 0.56 5:40 0.9 0.23 0.13 0.05 0.175 0.267 80.16 0.00 0.00 0.00 0.00 0.00 80.16 0.00 0.00 0.00 0.00 80.16 0.27 5:45 0.6 0.15 0.13 0.04 0.117 0.178 53.44 0.00 0.00 0.00 0.00 0.00 53.44 0.00 0.00 0.00 0.00 53.44 0.18 5:50 0.5 0.13 0.13 0.03 0.097 0.148 44.54 0.00 0.00 0.00 0.00 0.00 44.54 0.00 0.00 0.00 0.00 44.54 0.15 5:55 0.3 0.08 0.13 0.02 0.058 0.089 26.72 0.00 0.00 0.00 0.00 0.00 26.72 0.00 0.00 0.00 0.00 26.72 0.09 6:00 0.2 0.05 0.13 0.01 0.039 0.059 17.81 0.00 0.00 0.00 0.00 0.00 17.81 0.00 0.00 0.00 0.00 17.81 0.06 Total volume (CF)9290.73 Total Overflow (CF)9290.73
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10 -year 24 Hour Storm in 15 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:15 0.2 0.03 0.23 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 0:30 0.3 0.05 0.23 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 0:45 0.3 0.05 0.22 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 1:00 0.4 0.07 0.22 0.02 0.053 0.080 72.09 0.00 0.00 0.00 0.00 0.00 72.09 0.00 0.00 0.00 0.00 72.09 0.08 1:15 0.3 0.05 0.22 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 1:30 0.3 0.05 0.22 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 1:45 0.3 0.05 0.21 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 2:00 0.4 0.07 0.21 0.02 0.053 0.080 72.09 0.00 0.00 0.00 0.00 0.00 72.09 0.00 0.00 0.00 0.00 72.09 0.08 2:15 0.4 0.07 0.21 0.02 0.053 0.080 72.09 0.00 0.00 0.00 0.00 0.00 72.09 0.00 0.00 0.00 0.00 72.09 0.08 2:30 0.4 0.07 0.20 0.02 0.053 0.080 72.09 0.00 0.00 0.00 0.00 0.00 72.09 0.00 0.00 0.00 0.00 72.09 0.08 2:45 0.5 0.09 0.20 0.02 0.066 0.100 90.12 0.00 0.00 0.00 0.00 0.00 90.12 0.00 0.00 0.00 0.00 90.12 0.10 3:00 0.5 0.09 0.20 0.02 0.066 0.100 90.12 0.00 0.00 0.00 0.00 0.00 90.12 0.00 0.00 0.00 0.00 90.12 0.10 3:15 0.5 0.09 0.20 0.02 0.066 0.100 90.12 0.00 0.00 0.00 0.00 0.00 90.12 0.00 0.00 0.00 0.00 90.12 0.10 3:30 0.5 0.09 0.19 0.02 0.066 0.100 90.12 0.00 0.00 0.00 0.00 0.00 90.12 0.00 0.00 0.00 0.00 90.12 0.10 3:45 0.5 0.09 0.19 0.02 0.066 0.100 90.12 0.00 0.00 0.00 0.00 0.00 90.12 0.00 0.00 0.00 0.00 90.12 0.10 4:00 0.6 0.10 0.19 0.02 0.079 0.120 108.14 0.00 0.00 0.00 0.00 0.00 108.14 0.00 0.00 0.00 0.00 108.14 0.12 4:15 0.6 0.10 0.19 0.02 0.079 0.120 108.14 0.00 0.00 0.00 0.00 0.00 108.14 0.00 0.00 0.00 0.00 108.14 0.12 4:30 0.7 0.12 0.19 0.03 0.092 0.140 126.16 0.00 0.00 0.00 0.00 0.00 126.16 0.00 0.00 0.00 0.00 126.16 0.14 4:45 0.7 0.12 0.18 0.03 0.092 0.140 126.16 0.00 0.00 0.00 0.00 0.00 126.16 0.00 0.00 0.00 0.00 126.16 0.14 5:00 0.8 0.14 0.18 0.03 0.105 0.160 144.19 0.00 0.00 0.00 0.00 0.00 144.19 0.00 0.00 0.00 0.00 144.19 0.16 5:15 0.6 0.10 0.18 0.02 0.079 0.120 108.14 0.00 0.00 0.00 0.00 0.00 108.14 0.00 0.00 0.00 0.00 108.14 0.12 5:30 0.7 0.12 0.18 0.03 0.092 0.140 126.16 0.00 0.00 0.00 0.00 0.00 126.16 0.00 0.00 0.00 0.00 126.16 0.14 5:45 0.8 0.14 0.17 0.03 0.105 0.160 144.19 0.00 0.00 0.00 0.00 0.00 144.19 0.00 0.00 0.00 0.00 144.19 0.16 6:00 0.8 0.14 0.17 0.03 0.105 0.160 144.19 0.00 0.00 0.00 0.00 0.00 144.19 0.00 0.00 0.00 0.00 144.19 0.16 6:15 0.9 0.16 0.17 0.04 0.118 0.180 162.21 0.00 0.00 0.00 0.00 0.00 162.21 0.00 0.00 0.00 0.00 162.21 0.18 6:30 0.9 0.16 0.17 0.04 0.118 0.180 162.21 0.00 0.00 0.00 0.00 0.00 162.21 0.00 0.00 0.00 0.00 162.21 0.18 6:45 1.0 0.17 0.16 0.04 0.131 0.200 180.23 0.00 0.00 0.00 0.00 0.00 180.23 0.00 0.00 0.00 0.00 180.23 0.20 7:00 1.0 0.17 0.16 0.04 0.131 0.200 180.23 0.00 0.00 0.00 0.00 0.00 180.23 0.00 0.00 0.00 0.00 180.23 0.20 7:15 1.0 0.17 0.16 0.04 0.131 0.200 180.23 0.00 0.00 0.00 0.00 0.00 180.23 0.00 0.00 0.00 0.00 180.23 0.20 7:30 1.1 0.19 0.16 0.05 0.145 0.220 198.25 0.00 0.00 0.00 0.00 0.00 198.25 0.00 0.00 0.00 0.00 198.25 0.22 7:45 1.2 0.21 0.16 0.05 0.158 0.240 216.28 0.00 0.00 0.00 0.00 0.00 216.28 0.00 0.00 0.00 0.00 216.28 0.24 8:00 1.3 0.22 0.15 0.05 0.171 0.260 234.30 0.00 0.00 0.00 0.00 0.00 234.30 0.00 0.00 0.00 0.00 234.30 0.26 8:15 1.5 0.26 0.15 0.06 0.197 0.300 270.35 0.00 0.00 0.00 0.00 0.00 270.35 0.00 0.00 0.00 0.00 270.35 0.30 8:30 1.5 0.26 0.15 0.06 0.197 0.300 270.35 0.00 0.00 0.00 0.00 0.00 270.35 0.00 0.00 0.00 0.00 270.35 0.30 8:45 1.6 0.28 0.15 0.07 0.210 0.320 288.37 0.00 0.00 0.00 0.00 0.00 288.37 0.00 0.00 0.00 0.00 288.37 0.32 9:00 1.7 0.29 0.15 0.07 0.223 0.340 306.39 0.00 0.00 0.00 0.00 0.00 306.39 0.00 0.00 0.00 0.00 306.39 0.34 9:15 1.9 0.33 0.14 0.08 0.250 0.380 342.44 0.00 0.00 0.00 0.00 0.00 342.44 0.00 0.00 0.00 0.00 342.44 0.38 9:30 2.0 0.34 0.14 0.08 0.263 0.401 360.46 0.00 0.00 0.00 0.00 0.00 360.46 0.00 0.00 0.00 0.00 360.46 0.40 9:45 2.1 0.36 0.14 0.09 0.276 0.421 378.49 0.00 0.00 0.00 0.00 0.00 378.49 0.00 0.00 0.00 0.00 378.49 0.42 10:00 2.2 0.38 0.14 0.09 0.289 0.441 396.51 0.00 0.00 0.00 0.00 0.00 396.51 0.00 0.00 0.00 0.00 396.51 0.44 10:15 1.5 0.26 0.13 0.06 0.197 0.300 270.35 0.00 0.00 0.00 0.00 0.00 270.35 0.00 0.00 0.00 0.00 270.35 0.30 10:30 1.5 0.26 0.13 0.06 0.197 0.300 270.35 0.00 0.00 0.00 0.00 0.00 270.35 0.00 0.00 0.00 0.00 270.35 0.30 10:45 2.0 0.34 0.13 0.08 0.263 0.401 360.46 0.00 0.00 0.00 0.00 0.00 360.46 0.00 0.00 0.00 0.00 360.46 0.40 11:00 2.0 0.34 0.13 0.08 0.263 0.401 360.46 0.00 0.00 0.00 0.00 0.00 360.46 0.00 0.00 0.00 0.00 360.46 0.40 11:15 1.9 0.33 0.13 0.08 0.250 0.380 342.44 0.00 0.00 0.00 0.00 0.00 342.44 0.00 0.00 0.00 0.00 342.44 0.38 11:30 1.9 0.33 0.13 0.08 0.250 0.380 342.44 0.00 0.00 0.00 0.00 0.00 342.44 0.00 0.00 0.00 0.00 342.44 0.38 11:45 1.7 0.29 0.12 0.07 0.223 0.340 306.39 0.00 0.00 0.00 0.00 0.00 306.39 0.00 0.00 0.00 0.00 306.39 0.34 12:00 1.8 0.31 0.12 0.07 0.237 0.360 324.42 0.00 0.00 0.00 0.00 0.00 324.42 0.00 0.00 0.00 0.00 324.42 0.36 12:15 2.5 0.43 0.12 0.10 0.329 0.501 450.58 0.00 0.00 0.00 0.00 0.00 450.58 0.00 0.00 0.00 0.00 450.58 0.50 17 of 24

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12:30 2.6 0.45 0.12 0.11 0.342 0.521 468.60 0.00 0.00 0.00 0.00 0.00 468.60 0.00 0.00 0.00 0.00 468.60 0.52 12:45 2.8 0.48 0.12 0.11 0.368 0.561 504.65 0.00 0.00 0.00 0.00 0.00 504.65 0.00 0.00 0.00 0.00 504.65 0.56 13:00 2.9 0.50 0.11 N/A 0.385 0.587 528.61 0.00 0.00 0.00 0.00 0.00 528.61 0.00 0.00 0.00 0.00 528.61 0.59 13:15 3.4 0.59 0.11 N/A 0.473 0.721 649.18 0.00 0.00 0.00 0.00 0.00 649.18 0.00 0.00 0.00 0.00 649.18 0.72 13:30 3.4 0.59 0.11 N/A 0.475 0.724 651.53 0.00 0.00 0.00 0.00 0.00 651.53 0.00 0.00 0.00 0.00 651.53 0.72 13:45 2.3 0.40 0.11 0.09 0.302 0.461 414.53 0.00 0.00 0.00 0.00 0.00 414.53 0.00 0.00 0.00 0.00 414.53 0.46 14:00 2.3 0.40 0.11 0.09 0.302 0.461 414.53 0.00 0.00 0.00 0.00 0.00 414.53 0.00 0.00 0.00 0.00 414.53 0.46 14:15 2.7 0.47 0.11 N/A 0.359 0.548 492.90 0.00 0.00 0.00 0.00 0.00 492.90 0.00 0.00 0.00 0.00 492.90 0.55 14:30 2.6 0.45 0.10 N/A 0.344 0.524 471.48 0.00 0.00 0.00 0.00 0.00 471.48 0.00 0.00 0.00 0.00 471.48 0.52 14:45 2.6 0.45 0.10 N/A 0.345 0.526 473.67 0.00 0.00 0.00 0.00 0.00 473.67 0.00 0.00 0.00 0.00 473.67 0.53 15:00 2.5 0.43 0.10 N/A 0.330 0.502 452.19 0.00 0.00 0.00 0.00 0.00 452.19 0.00 0.00 0.00 0.00 452.19 0.50 15:15 2.4 0.41 0.10 0.10 0.315 0.481 432.56 0.00 0.00 0.00 0.00 0.00 432.56 0.00 0.00 0.00 0.00 432.56 0.48 15:30 2.3 0.40 0.10 0.09 0.302 0.461 414.53 0.00 0.00 0.00 0.00 0.00 414.53 0.00 0.00 0.00 0.00 414.53 0.46 15:45 1.9 0.33 0.10 0.08 0.250 0.380 342.44 0.00 0.00 0.00 0.00 0.00 342.44 0.00 0.00 0.00 0.00 342.44 0.38 16:00 1.9 0.33 0.10 0.08 0.250 0.380 342.44 0.00 0.00 0.00 0.00 0.00 342.44 0.00 0.00 0.00 0.00 342.44 0.38 16:15 0.4 0.07 0.09 0.02 0.053 0.080 72.09 0.00 0.00 0.00 0.00 0.00 72.09 0.00 0.00 0.00 0.00 72.09 0.08 16:30 0.4 0.07 0.09 0.02 0.053 0.080 72.09 0.00 0.00 0.00 0.00 0.00 72.09 0.00 0.00 0.00 0.00 72.09 0.08 16:45 0.3 0.05 0.09 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 17:00 0.3 0.05 0.09 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 17:15 0.5 0.09 0.09 0.02 0.066 0.100 90.12 0.00 0.00 0.00 0.00 0.00 90.12 0.00 0.00 0.00 0.00 90.12 0.10 17:30 0.5 0.09 0.09 0.02 0.066 0.100 90.12 0.00 0.00 0.00 0.00 0.00 90.12 0.00 0.00 0.00 0.00 90.12 0.10 17:45 0.5 0.09 0.09 0.02 0.066 0.100 90.12 0.00 0.00 0.00 0.00 0.00 90.12 0.00 0.00 0.00 0.00 90.12 0.10 18:00 0.4 0.07 0.08 0.02 0.053 0.080 72.09 0.00 0.00 0.00 0.00 0.00 72.09 0.00 0.00 0.00 0.00 72.09 0.08 18:15 0.4 0.07 0.08 0.02 0.053 0.080 72.09 0.00 0.00 0.00 0.00 0.00 72.09 0.00 0.00 0.00 0.00 72.09 0.08 18:30 0.4 0.07 0.08 0.02 0.053 0.080 72.09 0.00 0.00 0.00 0.00 0.00 72.09 0.00 0.00 0.00 0.00 72.09 0.08 18:45 0.3 0.05 0.08 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 19:00 0.2 0.03 0.08 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 19:15 0.3 0.05 0.08 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 19:30 0.4 0.07 0.08 0.02 0.053 0.080 72.09 0.00 0.00 0.00 0.00 0.00 72.09 0.00 0.00 0.00 0.00 72.09 0.08 19:45 0.3 0.05 0.08 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 20:00 0.2 0.03 0.08 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 20:15 0.3 0.05 0.07 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 20:30 0.3 0.05 0.07 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 20:45 0.3 0.05 0.07 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 21:00 0.2 0.03 0.07 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 21:15 0.3 0.05 0.07 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 21:30 0.2 0.03 0.07 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 21:45 0.3 0.05 0.07 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 22:00 0.2 0.03 0.07 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 22:15 0.3 0.05 0.07 0.01 0.039 0.060 54.07 0.00 0.00 0.00 0.00 0.00 54.07 0.00 0.00 0.00 0.00 54.07 0.06 22:30 0.2 0.03 0.07 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 22:45 0.2 0.03 0.07 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 23:00 0.2 0.03 0.07 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 23:15 0.2 0.03 0.07 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 23:30 0.2 0.03 0.07 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 23:45 0.2 0.03 0.07 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 24:00 0.2 0.03 0.06 0.01 0.026 0.040 36.05 0.00 0.00 0.00 0.00 0.00 36.05 0.00 0.00 0.00 0.00 36.05 0.04 Total volume (CF)18120.03 Total Overflow (CF)18120.03
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Project:Beaumont Post-Development
Recurrence Interval 100 year
Storm Duration (hrs)1 3 6 24
100-year NOAA Atlas 14 Point Precipitation (in)1.920 2.570 3.460 6.730 Unit time (minutes)5 5 5 15
Drainage Area 65819 SF 1.511 Ac.

Basin volume is calculated using the "truncated pyramid" formula, a more conservative estimate than "averaged end areas" sometimes used (Drywell can be "zeroed out" by reducing numbers to less than .001, but should not entered as zeros or program chokes.) Drywell storage includes 40% of the 1' wide rock bed surrounding the drywell: formula (upper)*PI()*(diam/2)^2+(lower)*PI()*((diam/2)^2+0.4*((diam/2+(grav+0.4166))^2-(diam/2+0.4166)^2)) The drywell wall thickness is assumed at 5" (0.4166) and the gravel bed width is variable "grav" Drywell design factors
Upper sec. (FT)=0.0001 Lower sec. (FT)=0.0001 Ring diam. (FT) =0.0001 Gravel bed width around drywell=0.0001 Drywell lower max. (CF)=0.00 Upper max.(CF)=0.00 Drywell total(CF)=0.00 Retention Basin design factors
Top (SF)=0.0001 Bot. (SF)=0.0001 Max. Depth (FT)=0.0001 Max. storage (CF)=0.00 (d/3)*(bottom+top+(bottom*top)^0.50) Formulas vol=(h/3)*(bottom+top+(bottom*top)^0.50) area=bottom+(h/d)*(top-bottom)h=(vol*3)/(bottom+top+(bottom*top)^0.5) 100 -year 1 Hour Storm in 5 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:05 3.7 0.85 0.13 N/A 0.723 1.101 330.25 0.00 0.00 0.00 0.00 0.00 330.25 0.00 0.00 0.00 0.00 330.25 1.10 0:10 4.8 1.11 0.13 N/A 0.976 1.487 446.09 0.00 0.00 0.00 0.00 0.00 446.09 0.00 0.00 0.00 0.00 446.09 1.49 0:15 5.1 1.18 0.13 N/A 1.045 1.592 477.69 0.00 0.00 0.00 0.00 0.00 477.69 0.00 0.00 0.00 0.00 477.69 1.59 0:20 4.9 1.13 0.13 N/A 0.999 1.522 456.63 0.00 0.00 0.00 0.00 0.00 456.63 0.00 0.00 0.00 0.00 456.63 1.52 0:25 6.6 1.52 0.13 N/A 1.391 2.119 635.65 0.00 0.00 0.00 0.00 0.00 635.65 0.00 0.00 0.00 0.00 635.65 2.12 0:30 7.3 1.68 0.13 N/A 1.552 2.365 709.37 0.00 0.00 0.00 0.00 0.00 709.37 0.00 0.00 0.00 0.00 709.37 2.36 0:35 8.4 1.94 0.13 N/A 1.805 2.751 825.21 0.00 0.00 0.00 0.00 0.00 825.21 0.00 0.00 0.00 0.00 825.21 2.75 0:40 9.0 2.07 0.13 N/A 1.944 2.961 888.40 0.00 0.00 0.00 0.00 0.00 888.40 0.00 0.00 0.00 0.00 888.40 2.96 0:45 12.3 2.83 0.13 N/A 2.704 4.120 1235.92 0.00 0.00 0.00 0.00 0.00 1235.92 0.00 0.00 0.00 0.00 1235.92 4.12 0:50 17.6 4.06 0.13 N/A 3.925 5.980 1794.07 0.00 0.00 0.00 0.00 0.00 1794.07 0.00 0.00 0.00 0.00 1794.07 5.98 0:55 16.1 3.71 0.13 N/A 3.579 5.454 1636.10 0.00 0.00 0.00 0.00 0.00 1636.10 0.00 0.00 0.00 0.00 1636.10 5.45 1:00 4.2 0.97 0.13 N/A 0.838 1.276 382.91 0.00 0.00 0.00 0.00 0.00 382.91 0.00 0.00 0.00 0.00 382.91 1.28 Total volume (CF)9818.29 Total Overflow (CF)9818.29
RCFC&WCD Short Cut Unit Hydrograph Method
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100 -year 3 Hour Storm in 5 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:05 1.3 0.40 0.13 0.10 0.306 0.466 139.71 0.00 0.00 0.00 0.00 0.00 139.71 0.00 0.00 0.00 0.00 139.71 0.47 0:10 1.3 0.40 0.13 0.10 0.306 0.466 139.71 0.00 0.00 0.00 0.00 0.00 139.71 0.00 0.00 0.00 0.00 139.71 0.47 0:15 1.1 0.34 0.13 0.08 0.259 0.394 118.22 0.00 0.00 0.00 0.00 0.00 118.22 0.00 0.00 0.00 0.00 118.22 0.39 0:20 1.5 0.46 0.13 0.11 0.353 0.537 161.20 0.00 0.00 0.00 0.00 0.00 161.20 0.00 0.00 0.00 0.00 161.20 0.54 0:25 1.5 0.46 0.13 0.11 0.353 0.537 161.20 0.00 0.00 0.00 0.00 0.00 161.20 0.00 0.00 0.00 0.00 161.20 0.54 0:30 1.8 0.56 0.13 N/A 0.425 0.648 194.34 0.00 0.00 0.00 0.00 0.00 194.34 0.00 0.00 0.00 0.00 194.34 0.65 0:35 1.5 0.46 0.13 0.11 0.353 0.537 161.20 0.00 0.00 0.00 0.00 0.00 161.20 0.00 0.00 0.00 0.00 161.20 0.54 0:40 1.8 0.56 0.13 N/A 0.425 0.648 194.34 0.00 0.00 0.00 0.00 0.00 194.34 0.00 0.00 0.00 0.00 194.34 0.65 0:45 1.8 0.56 0.13 N/A 0.425 0.648 194.34 0.00 0.00 0.00 0.00 0.00 194.34 0.00 0.00 0.00 0.00 194.34 0.65 0:50 1.5 0.46 0.13 0.11 0.353 0.537 161.20 0.00 0.00 0.00 0.00 0.00 161.20 0.00 0.00 0.00 0.00 161.20 0.54 0:55 1.6 0.49 0.13 0.12 0.376 0.573 171.95 0.00 0.00 0.00 0.00 0.00 171.95 0.00 0.00 0.00 0.00 171.95 0.57 1:00 1.8 0.56 0.13 N/A 0.425 0.648 194.34 0.00 0.00 0.00 0.00 0.00 194.34 0.00 0.00 0.00 0.00 194.34 0.65 1:05 2.2 0.68 0.13 N/A 0.549 0.836 250.72 0.00 0.00 0.00 0.00 0.00 250.72 0.00 0.00 0.00 0.00 250.72 0.84 1:10 2.2 0.68 0.13 N/A 0.549 0.836 250.72 0.00 0.00 0.00 0.00 0.00 250.72 0.00 0.00 0.00 0.00 250.72 0.84 1:15 2.2 0.68 0.13 N/A 0.549 0.836 250.72 0.00 0.00 0.00 0.00 0.00 250.72 0.00 0.00 0.00 0.00 250.72 0.84 1:20 2.0 0.62 0.13 N/A 0.487 0.742 222.53 0.00 0.00 0.00 0.00 0.00 222.53 0.00 0.00 0.00 0.00 222.53 0.74 1:25 2.6 0.80 0.13 N/A 0.672 1.024 307.11 0.00 0.00 0.00 0.00 0.00 307.11 0.00 0.00 0.00 0.00 307.11 1.02 1:30 2.7 0.83 0.13 N/A 0.703 1.071 321.20 0.00 0.00 0.00 0.00 0.00 321.20 0.00 0.00 0.00 0.00 321.20 1.07 1:35 2.4 0.74 0.13 N/A 0.610 0.930 278.91 0.00 0.00 0.00 0.00 0.00 278.91 0.00 0.00 0.00 0.00 278.91 0.93 1:40 2.7 0.83 0.13 N/A 0.703 1.071 321.20 0.00 0.00 0.00 0.00 0.00 321.20 0.00 0.00 0.00 0.00 321.20 1.07 1:45 3.3 1.02 0.13 N/A 0.888 1.353 405.78 0.00 0.00 0.00 0.00 0.00 405.78 0.00 0.00 0.00 0.00 405.78 1.35 1:50 3.1 0.96 0.13 N/A 0.826 1.259 377.59 0.00 0.00 0.00 0.00 0.00 377.59 0.00 0.00 0.00 0.00 377.59 1.26 1:55 2.9 0.89 0.13 N/A 0.764 1.165 349.39 0.00 0.00 0.00 0.00 0.00 349.39 0.00 0.00 0.00 0.00 349.39 1.16 2:00 3.0 0.93 0.13 N/A 0.795 1.212 363.49 0.00 0.00 0.00 0.00 0.00 363.49 0.00 0.00 0.00 0.00 363.49 1.21 2:05 3.1 0.96 0.13 N/A 0.826 1.259 377.59 0.00 0.00 0.00 0.00 0.00 377.59 0.00 0.00 0.00 0.00 377.59 1.26 2:10 4.2 1.30 0.13 N/A 1.165 1.775 532.65 0.00 0.00 0.00 0.00 0.00 532.65 0.00 0.00 0.00 0.00 532.65 1.78 2:15 5.0 1.54 0.13 N/A 1.412 2.151 645.42 0.00 0.00 0.00 0.00 0.00 645.42 0.00 0.00 0.00 0.00 645.42 2.15 2:20 3.5 1.08 0.13 N/A 0.949 1.447 433.97 0.00 0.00 0.00 0.00 0.00 433.97 0.00 0.00 0.00 0.00 433.97 1.45 2:25 6.8 2.10 0.13 N/A 1.967 2.997 899.15 0.00 0.00 0.00 0.00 0.00 899.15 0.00 0.00 0.00 0.00 899.15 3.00 2:30 7.3 2.25 0.13 N/A 2.121 3.232 969.63 0.00 0.00 0.00 0.00 0.00 969.63 0.00 0.00 0.00 0.00 969.63 3.23 2:35 8.2 2.53 0.13 N/A 2.399 3.655 1096.50 0.00 0.00 0.00 0.00 0.00 1096.50 0.00 0.00 0.00 0.00 1096.50 3.65 2:40 5.9 1.82 0.13 N/A 1.690 2.574 772.28 0.00 0.00 0.00 0.00 0.00 772.28 0.00 0.00 0.00 0.00 772.28 2.57 2:45 2.0 0.62 0.13 N/A 0.487 0.742 222.53 0.00 0.00 0.00 0.00 0.00 222.53 0.00 0.00 0.00 0.00 222.53 0.74 2:50 1.8 0.56 0.13 N/A 0.425 0.648 194.34 0.00 0.00 0.00 0.00 0.00 194.34 0.00 0.00 0.00 0.00 194.34 0.65 2:55 1.8 0.56 0.13 N/A 0.425 0.648 194.34 0.00 0.00 0.00 0.00 0.00 194.34 0.00 0.00 0.00 0.00 194.34 0.65 3:00 0.6 0.19 0.13 0.04 0.141 0.215 64.48 0.00 0.00 0.00 0.00 0.00 64.48 0.00 0.00 0.00 0.00 64.48 0.21 Total volume (CF)12093.98 Total Overflow (CF)12093.98
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100 -year 6 Hour Storm in 5 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:05 0.5 0.21 0.13 0.05 0.158 0.241 72.34 0.00 0.00 0.00 0.00 0.00 72.34 0.00 0.00 0.00 0.00 72.34 0.24 0:10 0.6 0.25 0.13 0.06 0.190 0.289 86.81 0.00 0.00 0.00 0.00 0.00 86.81 0.00 0.00 0.00 0.00 86.81 0.29 0:15 0.6 0.25 0.13 0.06 0.190 0.289 86.81 0.00 0.00 0.00 0.00 0.00 86.81 0.00 0.00 0.00 0.00 86.81 0.29 0:20 0.6 0.25 0.13 0.06 0.190 0.289 86.81 0.00 0.00 0.00 0.00 0.00 86.81 0.00 0.00 0.00 0.00 86.81 0.29 0:25 0.6 0.25 0.13 0.06 0.190 0.289 86.81 0.00 0.00 0.00 0.00 0.00 86.81 0.00 0.00 0.00 0.00 86.81 0.29 0:30 0.7 0.29 0.13 0.07 0.222 0.338 101.28 0.00 0.00 0.00 0.00 0.00 101.28 0.00 0.00 0.00 0.00 101.28 0.34 0:35 0.7 0.29 0.13 0.07 0.222 0.338 101.28 0.00 0.00 0.00 0.00 0.00 101.28 0.00 0.00 0.00 0.00 101.28 0.34 0:40 0.7 0.29 0.13 0.07 0.222 0.338 101.28 0.00 0.00 0.00 0.00 0.00 101.28 0.00 0.00 0.00 0.00 101.28 0.34 0:45 0.7 0.29 0.13 0.07 0.222 0.338 101.28 0.00 0.00 0.00 0.00 0.00 101.28 0.00 0.00 0.00 0.00 101.28 0.34 0:50 0.7 0.29 0.13 0.07 0.222 0.338 101.28 0.00 0.00 0.00 0.00 0.00 101.28 0.00 0.00 0.00 0.00 101.28 0.34 0:55 0.7 0.29 0.13 0.07 0.222 0.338 101.28 0.00 0.00 0.00 0.00 0.00 101.28 0.00 0.00 0.00 0.00 101.28 0.34 1:00 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 1:05 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 1:10 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 1:15 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 1:20 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 1:25 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 1:30 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 1:35 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 1:40 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 1:45 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 1:50 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 1:55 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 2:00 0.9 0.37 0.13 0.09 0.285 0.434 130.22 0.00 0.00 0.00 0.00 0.00 130.22 0.00 0.00 0.00 0.00 130.22 0.43 2:05 0.8 0.33 0.13 0.08 0.253 0.386 115.75 0.00 0.00 0.00 0.00 0.00 115.75 0.00 0.00 0.00 0.00 115.75 0.39 2:10 0.9 0.37 0.13 0.09 0.285 0.434 130.22 0.00 0.00 0.00 0.00 0.00 130.22 0.00 0.00 0.00 0.00 130.22 0.43 2:15 0.9 0.37 0.13 0.09 0.285 0.434 130.22 0.00 0.00 0.00 0.00 0.00 130.22 0.00 0.00 0.00 0.00 130.22 0.43 2:20 0.9 0.37 0.13 0.09 0.285 0.434 130.22 0.00 0.00 0.00 0.00 0.00 130.22 0.00 0.00 0.00 0.00 130.22 0.43 2:25 0.9 0.37 0.13 0.09 0.285 0.434 130.22 0.00 0.00 0.00 0.00 0.00 130.22 0.00 0.00 0.00 0.00 130.22 0.43 2:30 0.9 0.37 0.13 0.09 0.285 0.434 130.22 0.00 0.00 0.00 0.00 0.00 130.22 0.00 0.00 0.00 0.00 130.22 0.43 2:35 0.9 0.37 0.13 0.09 0.285 0.434 130.22 0.00 0.00 0.00 0.00 0.00 130.22 0.00 0.00 0.00 0.00 130.22 0.43 2:40 0.9 0.37 0.13 0.09 0.285 0.434 130.22 0.00 0.00 0.00 0.00 0.00 130.22 0.00 0.00 0.00 0.00 130.22 0.43 2:45 1.0 0.42 0.13 0.10 0.317 0.482 144.69 0.00 0.00 0.00 0.00 0.00 144.69 0.00 0.00 0.00 0.00 144.69 0.48 2:50 1.0 0.42 0.13 0.10 0.317 0.482 144.69 0.00 0.00 0.00 0.00 0.00 144.69 0.00 0.00 0.00 0.00 144.69 0.48 2:55 1.0 0.42 0.13 0.10 0.317 0.482 144.69 0.00 0.00 0.00 0.00 0.00 144.69 0.00 0.00 0.00 0.00 144.69 0.48 3:00 1.0 0.42 0.13 0.10 0.317 0.482 144.69 0.00 0.00 0.00 0.00 0.00 144.69 0.00 0.00 0.00 0.00 144.69 0.48 3:05 1.0 0.42 0.13 0.10 0.317 0.482 144.69 0.00 0.00 0.00 0.00 0.00 144.69 0.00 0.00 0.00 0.00 144.69 0.48 3:10 1.1 0.46 0.13 0.11 0.348 0.531 159.16 0.00 0.00 0.00 0.00 0.00 159.16 0.00 0.00 0.00 0.00 159.16 0.53 3:15 1.1 0.46 0.13 0.11 0.348 0.531 159.16 0.00 0.00 0.00 0.00 0.00 159.16 0.00 0.00 0.00 0.00 159.16 0.53 3:20 1.1 0.46 0.13 0.11 0.348 0.531 159.16 0.00 0.00 0.00 0.00 0.00 159.16 0.00 0.00 0.00 0.00 159.16 0.53 3:25 1.2 0.50 0.13 0.12 0.380 0.579 173.62 0.00 0.00 0.00 0.00 0.00 173.62 0.00 0.00 0.00 0.00 173.62 0.58 3:30 1.3 0.54 0.13 0.13 0.412 0.627 188.09 0.00 0.00 0.00 0.00 0.00 188.09 0.00 0.00 0.00 0.00 188.09 0.63 3:35 1.4 0.58 0.13 N/A 0.451 0.688 206.29 0.00 0.00 0.00 0.00 0.00 206.29 0.00 0.00 0.00 0.00 206.29 0.69 3:40 1.4 0.58 0.13 N/A 0.451 0.688 206.29 0.00 0.00 0.00 0.00 0.00 206.29 0.00 0.00 0.00 0.00 206.29 0.69 3:45 1.5 0.62 0.13 N/A 0.493 0.751 225.27 0.00 0.00 0.00 0.00 0.00 225.27 0.00 0.00 0.00 0.00 225.27 0.75 3:50 1.5 0.62 0.13 N/A 0.493 0.751 225.27 0.00 0.00 0.00 0.00 0.00 225.27 0.00 0.00 0.00 0.00 225.27 0.75 3:55 1.6 0.66 0.13 N/A 0.534 0.814 244.25 0.00 0.00 0.00 0.00 0.00 244.25 0.00 0.00 0.00 0.00 244.25 0.81 4:00 1.6 0.66 0.13 N/A 0.534 0.814 244.25 0.00 0.00 0.00 0.00 0.00 244.25 0.00 0.00 0.00 0.00 244.25 0.81 4:05 1.7 0.71 0.13 N/A 0.576 0.877 263.23 0.00 0.00 0.00 0.00 0.00 263.23 0.00 0.00 0.00 0.00 263.23 0.88 21 of 24

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4:10 1.8 0.75 0.13 N/A 0.617 0.941 282.20 0.00 0.00 0.00 0.00 0.00 282.20 0.00 0.00 0.00 0.00 282.20 0.94 4:15 1.9 0.79 0.13 N/A 0.659 1.004 301.18 0.00 0.00 0.00 0.00 0.00 301.18 0.00 0.00 0.00 0.00 301.18 1.00 4:20 2.0 0.83 0.13 N/A 0.700 1.067 320.16 0.00 0.00 0.00 0.00 0.00 320.16 0.00 0.00 0.00 0.00 320.16 1.07 4:25 2.1 0.87 0.13 N/A 0.742 1.130 339.14 0.00 0.00 0.00 0.00 0.00 339.14 0.00 0.00 0.00 0.00 339.14 1.13 4:30 2.1 0.87 0.13 N/A 0.742 1.130 339.14 0.00 0.00 0.00 0.00 0.00 339.14 0.00 0.00 0.00 0.00 339.14 1.13 4:35 2.2 0.91 0.13 N/A 0.783 1.194 358.12 0.00 0.00 0.00 0.00 0.00 358.12 0.00 0.00 0.00 0.00 358.12 1.19 4:40 2.3 0.95 0.13 N/A 0.825 1.257 377.09 0.00 0.00 0.00 0.00 0.00 377.09 0.00 0.00 0.00 0.00 377.09 1.26 4:45 2.4 1.00 0.13 N/A 0.867 1.320 396.07 0.00 0.00 0.00 0.00 0.00 396.07 0.00 0.00 0.00 0.00 396.07 1.32 4:50 2.4 1.00 0.13 N/A 0.867 1.320 396.07 0.00 0.00 0.00 0.00 0.00 396.07 0.00 0.00 0.00 0.00 396.07 1.32 4:55 2.5 1.04 0.13 N/A 0.908 1.383 415.05 0.00 0.00 0.00 0.00 0.00 415.05 0.00 0.00 0.00 0.00 415.05 1.38 5:00 2.6 1.08 0.13 N/A 0.950 1.447 434.03 0.00 0.00 0.00 0.00 0.00 434.03 0.00 0.00 0.00 0.00 434.03 1.45 5:05 3.1 1.29 0.13 N/A 1.157 1.763 528.92 0.00 0.00 0.00 0.00 0.00 528.92 0.00 0.00 0.00 0.00 528.92 1.76 5:10 3.6 1.49 0.13 N/A 1.365 2.079 623.81 0.00 0.00 0.00 0.00 0.00 623.81 0.00 0.00 0.00 0.00 623.81 2.08 5:15 3.9 1.62 0.13 N/A 1.489 2.269 680.74 0.00 0.00 0.00 0.00 0.00 680.74 0.00 0.00 0.00 0.00 680.74 2.27 5:20 4.2 1.74 0.13 N/A 1.614 2.459 737.67 0.00 0.00 0.00 0.00 0.00 737.67 0.00 0.00 0.00 0.00 737.67 2.46 5:25 4.7 1.95 0.13 N/A 1.821 2.775 832.56 0.00 0.00 0.00 0.00 0.00 832.56 0.00 0.00 0.00 0.00 832.56 2.78 5:30 5.6 2.33 0.13 N/A 2.195 3.345 1003.36 0.00 0.00 0.00 0.00 0.00 1003.36 0.00 0.00 0.00 0.00 1003.36 3.34 5:35 1.9 0.79 0.13 N/A 0.659 1.004 301.18 0.00 0.00 0.00 0.00 0.00 301.18 0.00 0.00 0.00 0.00 301.18 1.00 5:40 0.9 0.37 0.13 0.09 0.285 0.434 130.22 0.00 0.00 0.00 0.00 0.00 130.22 0.00 0.00 0.00 0.00 130.22 0.43 5:45 0.6 0.25 0.13 0.06 0.190 0.289 86.81 0.00 0.00 0.00 0.00 0.00 86.81 0.00 0.00 0.00 0.00 86.81 0.29 5:50 0.5 0.21 0.13 0.05 0.158 0.241 72.34 0.00 0.00 0.00 0.00 0.00 72.34 0.00 0.00 0.00 0.00 72.34 0.24 5:55 0.3 0.12 0.13 0.03 0.095 0.145 43.41 0.00 0.00 0.00 0.00 0.00 43.41 0.00 0.00 0.00 0.00 43.41 0.14 6:00 0.2 0.08 0.13 0.02 0.063 0.096 28.94 0.00 0.00 0.00 0.00 0.00 28.94 0.00 0.00 0.00 0.00 28.94 0.10 Total volume (CF)15779.45 Total Overflow (CF)15779.45
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100 -year 24 Hour Storm in 15 minute increments
Drywell Drywell Drywell Drywell Overflow Basin Basin Basin Time Pattern Storm Loss Rate Effective Flow Flow Outside Retention Period Storage Storage To Retention Period Storage Storage Overflow Overflow %Rain (in/hr)Value Max.Min.Rain (in/hr)Rate (CFS)Vol. (CF)Input (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Basin (CF)Area (sf)Perc. (CF)Vol. (CF)Depth (ft)Vol. (CF)Rate (CFS) 0:15 0.2 0.05 0.23 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 0:30 0.3 0.08 0.23 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 0:45 0.3 0.08 0.22 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 1:00 0.4 0.11 0.22 0.03 0.082 0.125 112.57 0.00 0.00 0.00 0.00 0.00 112.57 0.00 0.00 0.00 0.00 112.57 0.13 1:15 0.3 0.08 0.22 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 1:30 0.3 0.08 0.22 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 1:45 0.3 0.08 0.21 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 2:00 0.4 0.11 0.21 0.03 0.082 0.125 112.57 0.00 0.00 0.00 0.00 0.00 112.57 0.00 0.00 0.00 0.00 112.57 0.13 2:15 0.4 0.11 0.21 0.03 0.082 0.125 112.57 0.00 0.00 0.00 0.00 0.00 112.57 0.00 0.00 0.00 0.00 112.57 0.13 2:30 0.4 0.11 0.20 0.03 0.082 0.125 112.57 0.00 0.00 0.00 0.00 0.00 112.57 0.00 0.00 0.00 0.00 112.57 0.13 2:45 0.5 0.13 0.20 0.03 0.103 0.156 140.71 0.00 0.00 0.00 0.00 0.00 140.71 0.00 0.00 0.00 0.00 140.71 0.16 3:00 0.5 0.13 0.20 0.03 0.103 0.156 140.71 0.00 0.00 0.00 0.00 0.00 140.71 0.00 0.00 0.00 0.00 140.71 0.16 3:15 0.5 0.13 0.20 0.03 0.103 0.156 140.71 0.00 0.00 0.00 0.00 0.00 140.71 0.00 0.00 0.00 0.00 140.71 0.16 3:30 0.5 0.13 0.19 0.03 0.103 0.156 140.71 0.00 0.00 0.00 0.00 0.00 140.71 0.00 0.00 0.00 0.00 140.71 0.16 3:45 0.5 0.13 0.19 0.03 0.103 0.156 140.71 0.00 0.00 0.00 0.00 0.00 140.71 0.00 0.00 0.00 0.00 140.71 0.16 4:00 0.6 0.16 0.19 0.04 0.123 0.188 168.86 0.00 0.00 0.00 0.00 0.00 168.86 0.00 0.00 0.00 0.00 168.86 0.19 4:15 0.6 0.16 0.19 0.04 0.123 0.188 168.86 0.00 0.00 0.00 0.00 0.00 168.86 0.00 0.00 0.00 0.00 168.86 0.19 4:30 0.7 0.19 0.19 0.04 0.144 0.219 197.00 0.00 0.00 0.00 0.00 0.00 197.00 0.00 0.00 0.00 0.00 197.00 0.22 4:45 0.7 0.19 0.18 0.04 0.144 0.219 197.00 0.00 0.00 0.00 0.00 0.00 197.00 0.00 0.00 0.00 0.00 197.00 0.22 5:00 0.8 0.22 0.18 0.05 0.164 0.250 225.14 0.00 0.00 0.00 0.00 0.00 225.14 0.00 0.00 0.00 0.00 225.14 0.25 5:15 0.6 0.16 0.18 0.04 0.123 0.188 168.86 0.00 0.00 0.00 0.00 0.00 168.86 0.00 0.00 0.00 0.00 168.86 0.19 5:30 0.7 0.19 0.18 0.04 0.144 0.219 197.00 0.00 0.00 0.00 0.00 0.00 197.00 0.00 0.00 0.00 0.00 197.00 0.22 5:45 0.8 0.22 0.17 0.05 0.164 0.250 225.14 0.00 0.00 0.00 0.00 0.00 225.14 0.00 0.00 0.00 0.00 225.14 0.25 6:00 0.8 0.22 0.17 0.05 0.164 0.250 225.14 0.00 0.00 0.00 0.00 0.00 225.14 0.00 0.00 0.00 0.00 225.14 0.25 6:15 0.9 0.24 0.17 0.06 0.185 0.281 253.29 0.00 0.00 0.00 0.00 0.00 253.29 0.00 0.00 0.00 0.00 253.29 0.28 6:30 0.9 0.24 0.17 0.06 0.185 0.281 253.29 0.00 0.00 0.00 0.00 0.00 253.29 0.00 0.00 0.00 0.00 253.29 0.28 6:45 1.0 0.27 0.16 0.06 0.205 0.313 281.43 0.00 0.00 0.00 0.00 0.00 281.43 0.00 0.00 0.00 0.00 281.43 0.31 7:00 1.0 0.27 0.16 0.06 0.205 0.313 281.43 0.00 0.00 0.00 0.00 0.00 281.43 0.00 0.00 0.00 0.00 281.43 0.31 7:15 1.0 0.27 0.16 0.06 0.205 0.313 281.43 0.00 0.00 0.00 0.00 0.00 281.43 0.00 0.00 0.00 0.00 281.43 0.31 7:30 1.1 0.30 0.16 0.07 0.226 0.344 309.57 0.00 0.00 0.00 0.00 0.00 309.57 0.00 0.00 0.00 0.00 309.57 0.34 7:45 1.2 0.32 0.16 0.08 0.246 0.375 337.71 0.00 0.00 0.00 0.00 0.00 337.71 0.00 0.00 0.00 0.00 337.71 0.38 8:00 1.3 0.35 0.15 0.08 0.267 0.407 365.86 0.00 0.00 0.00 0.00 0.00 365.86 0.00 0.00 0.00 0.00 365.86 0.41 8:15 1.5 0.40 0.15 0.10 0.308 0.469 422.14 0.00 0.00 0.00 0.00 0.00 422.14 0.00 0.00 0.00 0.00 422.14 0.47 8:30 1.5 0.40 0.15 0.10 0.308 0.469 422.14 0.00 0.00 0.00 0.00 0.00 422.14 0.00 0.00 0.00 0.00 422.14 0.47 8:45 1.6 0.43 0.15 0.10 0.328 0.500 450.29 0.00 0.00 0.00 0.00 0.00 450.29 0.00 0.00 0.00 0.00 450.29 0.50 9:00 1.7 0.46 0.15 0.11 0.349 0.532 478.43 0.00 0.00 0.00 0.00 0.00 478.43 0.00 0.00 0.00 0.00 478.43 0.53 9:15 1.9 0.51 0.14 0.12 0.390 0.594 534.71 0.00 0.00 0.00 0.00 0.00 534.71 0.00 0.00 0.00 0.00 534.71 0.59 9:30 2.0 0.54 0.14 0.13 0.410 0.625 562.86 0.00 0.00 0.00 0.00 0.00 562.86 0.00 0.00 0.00 0.00 562.86 0.63 9:45 2.1 0.57 0.14 0.13 0.431 0.657 591.00 0.00 0.00 0.00 0.00 0.00 591.00 0.00 0.00 0.00 0.00 591.00 0.66 10:00 2.2 0.59 0.14 N/A 0.455 0.694 624.39 0.00 0.00 0.00 0.00 0.00 624.39 0.00 0.00 0.00 0.00 624.39 0.69 10:15 1.5 0.40 0.13 0.10 0.308 0.469 422.14 0.00 0.00 0.00 0.00 0.00 422.14 0.00 0.00 0.00 0.00 422.14 0.47 10:30 1.5 0.40 0.13 0.10 0.308 0.469 422.14 0.00 0.00 0.00 0.00 0.00 422.14 0.00 0.00 0.00 0.00 422.14 0.47 10:45 2.0 0.54 0.13 0.13 0.410 0.625 562.86 0.00 0.00 0.00 0.00 0.00 562.86 0.00 0.00 0.00 0.00 562.86 0.63 11:00 2.0 0.54 0.13 0.13 0.410 0.625 562.86 0.00 0.00 0.00 0.00 0.00 562.86 0.00 0.00 0.00 0.00 562.86 0.63 11:15 1.9 0.51 0.13 0.12 0.390 0.594 534.71 0.00 0.00 0.00 0.00 0.00 534.71 0.00 0.00 0.00 0.00 534.71 0.59 11:30 1.9 0.51 0.13 0.12 0.390 0.594 534.71 0.00 0.00 0.00 0.00 0.00 534.71 0.00 0.00 0.00 0.00 534.71 0.59 11:45 1.7 0.46 0.12 0.11 0.349 0.532 478.43 0.00 0.00 0.00 0.00 0.00 478.43 0.00 0.00 0.00 0.00 478.43 0.53 12:00 1.8 0.48 0.12 0.12 0.369 0.563 506.57 0.00 0.00 0.00 0.00 0.00 506.57 0.00 0.00 0.00 0.00 506.57 0.56 12:15 2.5 0.67 0.12 N/A 0.553 0.843 758.58 0.00 0.00 0.00 0.00 0.00 758.58 0.00 0.00 0.00 0.00 758.58 0.84 23 of 24

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12:30 2.6 0.70 0.12 N/A 0.582 0.887 797.96 0.00 0.00 0.00 0.00 0.00 797.96 0.00 0.00 0.00 0.00 797.96 0.89 12:45 2.8 0.75 0.12 N/A 0.638 0.971 874.22 0.00 0.00 0.00 0.00 0.00 874.22 0.00 0.00 0.00 0.00 874.22 0.97 13:00 2.9 0.78 0.11 N/A 0.666 1.015 913.54 0.00 0.00 0.00 0.00 0.00 913.54 0.00 0.00 0.00 0.00 913.54 1.02 13:15 3.4 0.92 0.11 N/A 0.803 1.223 1100.48 0.00 0.00 0.00 0.00 0.00 1100.48 0.00 0.00 0.00 0.00 1100.48 1.22 13:30 3.4 0.92 0.11 N/A 0.804 1.225 1102.83 0.00 0.00 0.00 0.00 0.00 1102.83 0.00 0.00 0.00 0.00 1102.83 1.23 13:45 2.3 0.62 0.11 N/A 0.510 0.777 699.09 0.00 0.00 0.00 0.00 0.00 699.09 0.00 0.00 0.00 0.00 699.09 0.78 14:00 2.3 0.62 0.11 N/A 0.511 0.779 701.38 0.00 0.00 0.00 0.00 0.00 701.38 0.00 0.00 0.00 0.00 701.38 0.78 14:15 2.7 0.73 0.11 N/A 0.621 0.946 851.28 0.00 0.00 0.00 0.00 0.00 851.28 0.00 0.00 0.00 0.00 851.28 0.95 14:30 2.6 0.70 0.10 N/A 0.596 0.907 816.59 0.00 0.00 0.00 0.00 0.00 816.59 0.00 0.00 0.00 0.00 816.59 0.91 14:45 2.6 0.70 0.10 N/A 0.597 0.910 818.78 0.00 0.00 0.00 0.00 0.00 818.78 0.00 0.00 0.00 0.00 818.78 0.91 15:00 2.5 0.67 0.10 N/A 0.572 0.871 784.02 0.00 0.00 0.00 0.00 0.00 784.02 0.00 0.00 0.00 0.00 784.02 0.87 15:15 2.4 0.65 0.10 N/A 0.546 0.832 749.23 0.00 0.00 0.00 0.00 0.00 749.23 0.00 0.00 0.00 0.00 749.23 0.83 15:30 2.3 0.62 0.10 N/A 0.521 0.794 714.41 0.00 0.00 0.00 0.00 0.00 714.41 0.00 0.00 0.00 0.00 714.41 0.79 15:45 1.9 0.51 0.10 N/A 0.415 0.632 568.82 0.00 0.00 0.00 0.00 0.00 568.82 0.00 0.00 0.00 0.00 568.82 0.63 16:00 1.9 0.51 0.10 N/A 0.416 0.634 570.84 0.00 0.00 0.00 0.00 0.00 570.84 0.00 0.00 0.00 0.00 570.84 0.63 16:15 0.4 0.11 0.09 0.03 0.082 0.125 112.57 0.00 0.00 0.00 0.00 0.00 112.57 0.00 0.00 0.00 0.00 112.57 0.13 16:30 0.4 0.11 0.09 0.03 0.082 0.125 112.57 0.00 0.00 0.00 0.00 0.00 112.57 0.00 0.00 0.00 0.00 112.57 0.13 16:45 0.3 0.08 0.09 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 17:00 0.3 0.08 0.09 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 17:15 0.5 0.13 0.09 0.03 0.103 0.156 140.71 0.00 0.00 0.00 0.00 0.00 140.71 0.00 0.00 0.00 0.00 140.71 0.16 17:30 0.5 0.13 0.09 0.03 0.103 0.156 140.71 0.00 0.00 0.00 0.00 0.00 140.71 0.00 0.00 0.00 0.00 140.71 0.16 17:45 0.5 0.13 0.09 0.03 0.103 0.156 140.71 0.00 0.00 0.00 0.00 0.00 140.71 0.00 0.00 0.00 0.00 140.71 0.16 18:00 0.4 0.11 0.08 0.03 0.082 0.125 112.57 0.00 0.00 0.00 0.00 0.00 112.57 0.00 0.00 0.00 0.00 112.57 0.13 18:15 0.4 0.11 0.08 0.03 0.082 0.125 112.57 0.00 0.00 0.00 0.00 0.00 112.57 0.00 0.00 0.00 0.00 112.57 0.13 18:30 0.4 0.11 0.08 0.03 0.082 0.125 112.57 0.00 0.00 0.00 0.00 0.00 112.57 0.00 0.00 0.00 0.00 112.57 0.13 18:45 0.3 0.08 0.08 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 19:00 0.2 0.05 0.08 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 19:15 0.3 0.08 0.08 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 19:30 0.4 0.11 0.08 0.03 0.082 0.125 112.57 0.00 0.00 0.00 0.00 0.00 112.57 0.00 0.00 0.00 0.00 112.57 0.13 19:45 0.3 0.08 0.08 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 20:00 0.2 0.05 0.08 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 20:15 0.3 0.08 0.07 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 20:30 0.3 0.08 0.07 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 20:45 0.3 0.08 0.07 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 21:00 0.2 0.05 0.07 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 21:15 0.3 0.08 0.07 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 21:30 0.2 0.05 0.07 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 21:45 0.3 0.08 0.07 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 22:00 0.2 0.05 0.07 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 22:15 0.3 0.08 0.07 0.02 0.062 0.094 84.43 0.00 0.00 0.00 0.00 0.00 84.43 0.00 0.00 0.00 0.00 84.43 0.09 22:30 0.2 0.05 0.07 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 22:45 0.2 0.05 0.07 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 23:00 0.2 0.05 0.07 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 23:15 0.2 0.05 0.07 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 23:30 0.2 0.05 0.07 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 23:45 0.2 0.05 0.07 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 24:00 0.2 0.05 0.06 0.01 0.041 0.063 56.29 0.00 0.00 0.00 0.00 0.00 56.29 0.00 0.00 0.00 0.00 56.29 0.06 Total volume (CF)29403.43 Total Overflow (CF)29403.43
24 of 24

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G
Appendix G – Hydraulic Calculations

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Pre-Dev Runoff Volume 2 5 10 100
1 595.92 1189.43 3243.60 8227.38
3 582.85 1001.87 2778.79 7414.30
6 822.24 1191.35 3109.48 7731.16
24 1524.81 1985.54 3556.73 10394.72
Post-Dev Runoff Volume 2 5 10 100
1 2572.22 3577.06 4841.82 9818.29
3 4166.97 5379.37 6760.63 12093.98
6 6026.59 7611.52 9290.73 15779.45
24 11625.13 15137.76 18120.03 29403.43
BMP Storage Volume
DMA 1 0.00 cf
DMA 2 301.60 cf
DMA 3 338.40 cf
DMA 4 2914.56 cf
DMA 5 182.22 cf
BMP Volume 3736.778 cf
Runoff Volume Increase 2 5 10 100
1 1976.30 2387.63 1598.22 1590.91
3 3584.12 4377.50 3981.84 4679.68
6 5204.35 6420.17 6181.25 8048.29
24 10100.32 13152.22 14563.30 19008.71
Detention Volume Required
15271.9 cf

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*Ensure correct unit type is selected
Date:///
(in)
15272 (cf)35 (ft)40 %2584.86 (ft)2593 (ft)2592.02 (ft)
0 (in)0 (in)0 (in)0 (in)
Min. Burial Depth:23.5"WARNING: Burial Depth Too Shallow Max. Burial Depth:8'
1 of 20 &3 of 19 (sf)6415 (cf)(cf)8867 (cf)15451 (cf)
rows chambers rows chambers
(cy)1493 (sy)78 (sy)247 (sy)
V-4.7
77 8 594
Project Name:

Engineer:Contractor:

Harb-Beaumont
MTH2 Engineering, Inc
WARNING: Burial Depth Exceeds Recommendation

PROJECT DESCRIPTION

DESIGN CRITERIA - BASED ON STORAGE VOLUME

SYSTEM LAYOUT

SYSTEM STORAGE & QUANTITIES
1694521
City/State:

Phone #:

MLA
HS180Chamber Size
Target Storage
Volume
Additional Stone Above
Chamber*
Constraint on System
Dimensions Width
Constraint Limit
Additional Stone
Below Chamber*
Number of
Manifolds 2
Stone Porosity
Additional Stone
Side of Chamber*
Manifold Diameter 24
Bottom of Stone
Elevation
Additional Stone
Between Chambers*
Include Manifold
Volume?Yes
Max. Pavement
Elevation
Min. Pavement
Elevation
System Layout System Footprint Stone Storage Manifold Storage Chamber Storage Total System Storage Number of Chambers Number of End Caps Required Stone
(For Embedment Backfill)
Non-Woven Geotextile
(Includes 20% Overlap)
Woven Geotextile -Scour Woven Geotextile -Sediment Row
This tool is intended to assist in sizing stormwater management systems using Prinsco products. It should be used for estimating purposes only and is not intended to be a final design tool. The design engineer needs to verify all the values and ensure they meet all project design criteria.

ASSISTANCE: For assistance with design, drawings or pricing please have your completed system design aid ready, and contact your Prinsco sales representative * Minimum recommended values are already included in calculations 12"

45.5"
9"
12"8"

77.8"
*Units Standard

23.5"
Suitable
Non-woven
Stone
Foundation
Embedment
Initial Backfill
Final Backfill
Pavement
Avg. Design
System Depth

3.1'
NOTES ON COVER ABOVE CHAMBER:

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Peak Flowrate per DMA and Inlet Sizing
Shortcut Unit Hydrograph Peak Flowrate:

5.98 cfs 100-yr, 1-hr
Total Site Area:65819.04 sf 1.511 Ac.

Peak Inlet Size
DMA 1 1696.67 sf 2.58%0.154 cfs Self Retaining
DMA 2 5068.80 sf 7.70%0.461 cfs 18"x18" DI
DMA 3 5246.26 sf 7.97%0.477 cfs 18"x18" DI
DMA 4 51198.29 sf 77.79%4.652 cfs 24"x24" DI
DMA 5 2609.02 sf 3.96%0.237 cfs Self Retaining
100.00%

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Jensen 18"x18" Drop Inlet, assumes 2" ponding above top of grate.

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Jensen 24"x24" Drop Inlet, assumes 2" ponding above top of grate.

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Orifice Flow Calculations

Mathematically, the orifice flow equation gives the mass flow rate, or discharge Q through an orifice, given the area of the orifice A, and can be written as:

Q = Cd * A * √(2 * g * H)
where, Cd is coefficient of discharge, g is acceleration due to gravity in m/s2, and H being the mean center line (distance between the water level and the center of the orifice).

The coefficient of discharge, Cd is a function of various parameters such as the diameter of orifice d, acceleration due to gravity, hydraulic depth, and the kinematic viscosity of the fluid ν. Mathematically, it can be expressed as:

Cd ∝ (d * √(g * H) / ν)

Cd is approximately 0.60 per Table 4-6 in Handbook of Hydraulics by Brater and King.

A round orifice, 1.125” in diameter provides a maximum flow rate of 0.064 CFS under a maximum centerline head of 45” per the below calculation:

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Appendix 8: Source Control
Pollutant Sources/Source Control Checklist

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STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST How to use this worksheet (also see instructions in Section G of the WQMP Template): 1. Review Column 1 and identify which of these potential sources of stormwater pollutants apply to your site. Check each box that applies. 2. Review Column 2 and incorporate all of the corresponding applicable BMPs in your WQMP Exhibit. 3. Review Columns 3 and 4 and incorporate all of the corresponding applicable permanent controls and operational BMPs in your WQMP. Use the format shown in Table G.1on page 23 of this WQMP Template. Describe your specific BMPs in an accompanying narrative, and explain any special conditions or situations that required omitting BMPs or substituting alternative BMPs for those shown here. IF THESE SOURCES WILL BE ON THE PROJECT SITE … … THEN YOUR WQMP SHOULD INCLUDE THESE SOURCE CONTROL BMPs, AS APPLICABLE 1 Potential Sources of Runoff Pollutants 2 Permanent Controls—Show on WQMP Drawings 3 Permanent Controls—List in WQMP Table and Narrative 4 Operational BMPs—Include in WQMP Table and Narrative  A. On-site storm drain inlets  Locations of inlets. Mark all inlets with the words “Only Rain Down the Storm Drain” or similar. Catch Basin Markers may be available from the Riverside County Flood Control and Water Conservation District, call 951.955.1200 to verify.    Maintain and periodically repaint or replace inlet markings. Provide stormwater pollution prevention information to new site owners, lessees, or operators. See applicable operational BMPs in Fact Sheet SC-44, “Drainage System Maintenance,” in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com Include the following in lease agreements: “Tenant shall not allow anyone to discharge anything to storm drains or to store or deposit materials so as to create a potential discharge to storm drains.”  B. Interior floor drains and elevator shaft sump pumps State that interior floor drains and elevator shaft sump pumps will be plumbed to sanitary sewer.  Inspect and maintain drains to prevent blockages and overflow.  C. Interior parking garages State that parking garage floor drains will be plumbed to the sanitary sewer. Inspect and maintain drains to prevent blockages and overflow. √√√√√√√Page 305 of 1234

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST IF THESE SOURCES WILL BE ON THE PROJECT SITE … … THEN YOUR WQMP SHOULD INCLUDE THESE SOURCE CONTROL BMPs, AS APPLICABLE 1 Potential Sources of Runoff Pollutants 2 Permanent Controls—Show on WQMP Drawings 3 Permanent Controls—List in WQMP Table and Narrative 4 Operational BMPs—Include in WQMP Table and Narrative  E. Pools, spas, ponds, decorative fountains, and other water features.  Show location of water feature and a sanitary sewer cleanout in an accessible area within 10 feet. (Exception: Public pools must be plumbed according to County Department of Environmental Health Guidelines.) If the Co-Permittee requires pools to be plumbed to the sanitary sewer, place a note on the plans and state in the narrative that this connection will be made according to local requirements. See applicable operational BMPs in “Guidelines for Maintaining Your Swimming Pool, Jacuzzi and Garden Fountain” at http://rcflood.org/stormwater/  F. Food service   For restaurants, grocery stores, and other food service operations, show location (indoors or in a covered area outdoors) of a floor sink or other area for cleaning floor mats, containers, and equipment. On the drawing, show a note that this drain will be connected to a grease interceptor before discharging to the sanitary sewer.   Describe the location and features of the designated cleaning area. Describe the items to be cleaned in this facility and how it has been sized to insure that the largest items can be accommodated. See the brochure, “The Food Service Industry Best Management Practices for: Restaurants, Grocery Stores, Delicatessens and Bakeries” at http://rcflood.org/stormwater/ Provide this brochure to new site owners, lessees, and operators.  G. Refuse areas    Show where site refuse and recycled materials will be handled and stored for pickup. See local municipal requirements for sizes and other details of refuse areas. If dumpsters or other receptacles are outdoors, show how the designated area will be covered, graded, and paved to prevent run-on and show locations of berms to prevent runoff from the area. Any drains from dumpsters, compactors, and tallow bin areas shall be connected to a grease removal device before discharge to sanitary sewer.  State how site refuse will be handled and provide supporting detail to what is shown on plans. State that signs will be posted on or near dumpsters with the words “Do not dump hazardous materials here” or similar. State how the following will be implemented: Provide adequate number of receptacles. Inspect receptacles regularly; repair or replace leaky receptacles. Keep receptacles covered. Prohibit/prevent dumping of liquid or hazardous wastes. Post “no hazardous materials” signs. Inspect and pick up litter daily and clean up spills immediately. Keep spill control materials available on-site. See Fact Sheet SC-34, “Waste Handling and Disposal” in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com √√√√Page 307 of 1234

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST IF THESE SOURCES WILL BE ON THE PROJECT SITE … … THEN YOUR WQMP SHOULD INCLUDE THESE SOURCE CONTROL BMPs, AS APPLICABLE 1 Potential Sources of Runoff Pollutants 2 Permanent Controls—Show on WQMP Drawings 3 Permanent Controls—List in WQMP Table and Narrative 4 Operational BMPs—Include in WQMP Table and Narrative  K. Vehicle/Equipment Repair and Maintenance    Accommodate all vehicle equipment repair and maintenance indoors. Or designate an outdoor work area and design the area to prevent run-on and runoff of stormwater. Show secondary containment for exterior work areas where motor oil, brake fluid, gasoline, diesel fuel, radiator fluid, acid-containing batteries or other hazardous materials or hazardous wastes are used or stored. Drains shall not be installed within the secondary containment areas. Add a note on the plans that states either (1) there are no floor drains, or (2) floor drains are connected to wastewater pretreatment systems prior to discharge to the sanitary sewer and an industrial waste discharge permit will be obtained.   State that no vehicle repair or maintenance will be done outdoors, or else describe the required features of the outdoor work area. State that there are no floor drains or if there are floor drains, note the agency from which an industrial waste discharge permit will be obtained and that the design meets that agency’s requirements. State that there are no tanks, containers or sinks to be used for parts cleaning or rinsing or, if there are, note the agency from which an industrial waste discharge permit will be obtained and that the design meets that agency’s requirements.   In the Stormwater Control Plan, note that all of the following restrictions apply to use the site: No person shall dispose of, nor permit the disposal, directly or indirectly of vehicle fluids, hazardous materials, or rinsewater from parts cleaning into storm drains. No vehicle fluid removal shall be performed outside a building, nor on asphalt or ground surfaces, whether inside or outside a building, except in such a manner as to ensure that any spilled fluid will be in an area of secondary containment. Leaking vehicle fluids shall be contained or drained from the vehicle immediately. No person shall leave unattended drip parts or other open containers containing vehicle fluid, unless such containers are in use or in an area of secondary containment. Refer to “Automotive Maintenance & Car Care Best Management Practices for Auto Body Shops, Auto Repair Shops, Car Dealerships, Gas Stations and Fleet Service Operations”. Brochure can be found at http://rcflood.org/stormwater/ Refer to Outdoor Cleaning Activities and Professional Mobile Service Providers for many of the Potential Sources of Runoff Pollutants categories below. Brochure can be found at http://rcflood.org/stormwater/ Page 311 of 1234

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Appendix 9: O&M
Operation and Maintenance Plan and Documentation of Finance, Maintenance and Recording Mechanisms

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This Operations and Maintenance Plan (OMP) describes the designated responsible party for implementation of this plan and the project’s Water Quality Management Plan (WQMP), including:
operation and maintenance of all the structural Best Management Practices (BMPs), conducting training and educational programs, detailed inspection and maintenance requirements for all BMPs, manufacturer's maintenance requirements, permits, and any other necessary activities.

1. Project Information:

A portion of Parcel A, and Parcel B of Lot Line Adjustment xxx Site Size: 65,819 SF (1.511 AC)

2. The Responsible Party for implementation of this OMP and the WQMP is:

High Sand, Inc.
655 Highland Springs Avenue
Beaumont, CA, 92223

Contact Person: Ali Harb
Phone: (909) 214-3333
24-Hour Emergency Number: (909) 214-3333
Email: [email protected]

3. Record Keeping:

The Responsible Party shall retain OMP records for at least 5 years.

All training and educational activities, and BMP operation and maintenance shall be documented to verify compliance with this OMP Plan. A BMP Inspection and Maintenance Log, and a Training Log are included with this document.

The WQMP Verification Form shall be completed on an annual basis and retained as part of this document.

4. Vector Control

Standing water, which exists for longer than 72 hours may contribute to mosquito breeding areas. BMPs shall be inspected for standing water on a regular basis. Standing water may indicate that the BMPs are not functioning properly and proper action to remedy the situation shall be taken in a timely manner. Elimination of standing water and managing garbage, lawn clippings, and pet droppings, can help decrease the presence of mosquitoes and flies in the area.

The County Vector Control District may be contacted for more information and support.

5. Inspections

The local jurisdiction may conduct a site inspection to evaluate compliance with the project specific WQMP. The Responsible Party should keep this document, including the logs and the applicable WQMP, accessible on the project premises at all times and made available to the local jurisdiction inspector when requested as proof of maintenance.

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6. Operation and Maintenance Requirements

Reference the WQMP Site Plan included with this OMP for delineation and designation of pervious and impervious areas, locations and type of Stormwater BMPs, and locations of self- retaining areas addressed by LID principles that do not require specialized maintenance beyond that of typical landscape maintenance.

Reference the drain inlet insert filter manufacturer’s service and maintenance guides in Appendix 9.

The below listed fact sheets provide detailed information regarding operation and maintenance requirements for various features and activities expected. These fact sheets are included in Appendix 10 Educational Materials.

Non-Stormwater Management
SC-10 Non-Stormwater Discharges
SC-11 Spill Prevention, Control and Cleanup
Material and Waste Management
SC-30 Outdoor Loading/Unloading
SC-32 Outdoor Equipment Operations
SC-34 Waste Handling and Disposal
SC-35 Safer Alternative Products
Building and Grounds Management
SC-41 Building & Grounds Maintenance
SC-42 Building Repair and Construction
SC-43 Parking/Storage Area Maintenance
SC-44 Drainage System Maintenance

Appendix 10 also contains the following information pamphlets:

After the Storm
Stormwater Pollution for Automotive Maintenance and Car Care Stormwater Pollution for Outdoor Cleaning Activities and Professional Mobile Service Providers Only Rain Down the Storm Drain

The following chart provides additional operation and maintenance guidelines.

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BMP Inspection/Maintenance Required Minimum Frequency of Activities Responsible Party
Education for
Property Owners,
Tenants and
Occupants
Educational materials are provided in Appendix 10 of the WQMP.

Provide literature and instructions pertaining to environmental awareness to all employees, tenants and occupants. Keep log of persons receiving educational materials.

Once yearly and for new
employees, tenants and
occupants
Owner
Employee Training
Educate all employees on environmental awareness. Instruct on proper use of chemicals and clean-up procedures. Keep logs of employees and training dates.

Once yearly prior to storm
season Owner
Activity Restrictions
Any activity that may affect surrounding areas or downstream receiving waters such as car washing or leaving trash bin lids open is prohibited. Keep areas free of debris.

Trash areas shall be checked
before and after a storm
event
Owner
Irrigation
Inspect for siltation or debris washing out of planters. Sweep silt to planters and check amount of irrigation used and for properly functioning irrigation. Check irrigation system for leaks and over spray, provide maintenance as required.

Monthly Owner
Landscape, self-
retaining, and self-
treating areas
Check for landscape to be in healthy condition. Replace dead or barren areas with plants consistent with the approved landscape plans, remove trash and debris, ensure areas are depressed as required per the WQMP Site Plan.

Monthly Owner
Common Area
Landscape
Management
Hire contractor familiar with Riverside County guidelines for use of fertilizers and pesticides. Maintain all landscape equipment in proper working order.

Monthly Owner

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Common Area Litter
Control
Inspect trash enclosure area and bins for spill contamination and debris. Inspect site for debris. Keep areas free of debris. Monthly Owner Parking Lot Sweeping
Sweep by hand or machine sweeper, parking and drive areas. No hosing down of area with water is allowed. Properly dispose of debris offsite. Keep a log of sweeping activities.

Bi-monthly from October
15th thru April 15th and
before a storm event
Owner
Storm Drain System
and Drain Inlets
Inspect drain inlets and clean out debris and obstructions from inside inlet. Ensure inlet grate is properly installed.

Maintain insert filter per manufacturer’s service and maintenance guides.

Keep a log of inspection activities.

Inspect bi-monthly from
October 15th thru April 15th
and before a storm event.

Replace insert filter per
manufacturer’s replacement
guidelines
Owner
Prinsco Hydrostor
HS180 Chamber
System
Per manufacturer’s Retention/Detention Inspection and
Maintenance Guideline included in Appendix 9.

Bi-monthly from October
15th thru April 15th, and
before and after a storm
event
Owner
Bio-Retention BMP
Inspection
Maintain adjacent landscape and remove landscape debris from the infiltration basin area. Remove trash and debris from infiltration basin area.

Monthly and before a storm
event Owner
Bio-Retention BMP
Maintenance
Check for water ponding. If basin does not drain, excavate an additional 2-4 inches of soil. May be required every 5 to 10 years. 3 days after storm event Owner

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BMP Operation and Maintenance Log
Highland Springs Remodel and Development

Date:

Name of Person Performing Activity (Printed):

Signature:

BMP Name
(As Shown on WQMP Site Plan)
Brief Description of Implementation, Maintenance, and
Inspection Activity Performed

Page 321 of 1234 ends

Training and Educational Log
Highland Springs Remodel and Development

Date of Training/Educational Activity:

Name of Person Performing Activity (Printed):

Signature:

Topic of Training/Educational Activity:

Name of Participant Signature of Participant

For newsletter or mailer educational activities, please include the following information:

▪ Date of mailing
▪ Number distributed
▪ Method of distribution
▪ Topics addressed

If a newsletter article was distributed, please include a copy of it.

Page 322 of 1234 ends

Water Quality Management Plan Verification Survey
Highland Springs Remodel and Development

Responsible Party:

Contact Phone: Contact Email:

1. Have your contractors (landscape, maintenance, etc.) been educated regarding the applicable requirements to prevent pollution as outlined in the WQMP?

Yes No

Name of Landscape/Maintenance Contractor:

Method of education (contract language, Copy of O&M, educational brochures, etc.):

2. Have the storm drains and inlets been inspected and maintained, at a minimum, annually prior to Oct 1?

Yes No

Date of Last Inspection/Maintenance:

Maintenance conducted by:

3. Have you observed any runoff from the irrigation system?

Yes No If yes, how was the problem resolved?

4. What type of Integrated Pest Management (IPM) practices are used on site?

5. Are native and/or drought tolerant plants established and considered for any new landscaping?

Yes No

6. Have the storm drain stencils been inspected annually for legibility prior to Oct. 1?

Yes No

Total number of stencils on site:

How many inlets required re-stenciling / date of restenciling? /

Page 323 of 1234 ends

7. Have education materials been distributed to the residents/tenants/contractors within the past year?

Yes No

Topic / Date of Distribution: /

Method of Distribution: newsletter, billing insert, etc.:

8. Is street sweeping conducted weekly?

Yes No Contractor:

9. Are trash areas in common area inspected daily?

Yes No

10. Have any vector concerns been observed (standing water, mosquito larvae, etc.).

Yes No

11. Have the treatment BMPs been inspected and maintained per Manufacturer instructions? (attach invoices and inspection/maintenance forms).

Yes No

12. Have there been any issues with operation and maintenance of the treatment BMPs units?

I certify the above information is correct and the BMPs for this project have been implemented and operated and maintained in accordance with the Operation and Maintenance (O&M) Plan on site.

Print Name of Responsible Party

Signature Date

Page 324 of 1234 ends

X2589.5
X2589.6 2590X2590.6
X2590.6
2591
X2591.5
X2591.5 ASPH.2592X2592.5 2593X2593.5
X2593.5
X2589.3
2590
X2590.8
2591
X2591.2
X2591.3
X2591.4
X2591.5
X2591.5
X2591.7
CONC.
2592
2592
X2592.5
X2592.6
X2592.6
2592.7 2593CONC.

X2593.2
X2593.2
2593.4
X2593.8
2 5
9 4
X2595.3
X2595.4
X2595.7
X2595.8
25962596
X2596.3
X2596.3
X2597.5

DENSE TREES

18.00'

PRIVATE STORAGE CHAMBERS

PIPE CONNECTION TO

PROJECT LOCATION

SIDEWALK DRAIN

PROPOSED UNDER

WITH SOLID ROOF

PROPOSED TRASH ENCLOSURE

WITH SOLID ROOF

PROPOSED TRASH ENCLOSURE
DCV = 301.6 CF
Dgravel = 1.0'
Dsoil = 2.0'
A = 208 SF
BR 2
DCV = 338.4 CF
Dgravel = 1.0'
Dsoil = 2.0'
A = 240 SF
BR 3
DCV = 2,915.56 CF
Dgravel = 1.0'
Dsoil = 3.0'
A = 1,688 SF
BR 4

INTERCEPTOR

PROPOSED GREASE
1-3" CRUSHED STONE

PAVEMENT
BASE
1"-3" STONE FOUNDATION

SUITABLE SUB-GRADE

NON-WOVEN GEOTEXTILE
PRINSCO HYDROSTOR HS180 CHAMBER (TYP)

INITIAL BACKFILL
HS180 CHAMBER SYSTEM

PRINSCO HYDROSTOR

OVERFLOW INLET

86.85 IE

91.10 TG

84.43 IE 6"

87.61 IE 15"

90.61 TG

85.60 IE

92.78 TG

90.75 IE

94.00 TG

91.50 IE

94.75 TG

89.39 IE

92.37 TG

84.86 IE

WITH SOLID ROOF

PROPOSED VACUUM ENCLOSURE
BE DEPRESSED 2.2 INCHES.

DMA 5 SELF RETAINING AREA TO

UNDISTURBED NATURAL GROUND

FINISHED GRADE

0.5" - 1.5" CLEAN GRAVEL

SEE NOTES BELOW

ENGINEERED SOIL MEDIA,

TO OVERFLOW BASIN
6" PERFORATED PIPE TIED

PRECISE GRADING PLAN

OVERFLOW BASIN PER

PONDING LIMIT

FG PER PRECISE GRADING PLAN

GRADING PLAN

IE PER PRECISE

GRADING PLAN

IE PER PRECISE

PRECISE GRADING PLAN

TO PARKWAY DRAIN PER

PROPOSED SUMP AND PUMP

PER PRECISE GRADING PLAN

PROPOSED PARKWAY DRAIN
6" PERFORATED PIPE
6" PERFORATED PIPE
6" PERFORATED PIPE
6" PERFORATED PIPE
8" PIPE
8" PIPE
8" PIPE
8" PIPE
8" PIPE 8" PIPE
15" PIPE
15" PIPE
15" PIPE

FIRST FLUSH SEDIMENT ROW
DMA 1
DMA 2
DMA 3
DMA 4
DMA 5

VICINITY MAP

NOT TO SCALEHIGHLAND SPRINGS AVEW RAMSEY ST
UPRR
10 W WILSON ST
ALEGHENY STW 5TH ST
e n g i n e e r i n g, i n c
MTH2 (951) 850-2190
Riverside, CA 92506
639 Lakewood Drive
urban design and planning
civil water resources storm water
www.mth2engineering.com
SCALE: 1" = 20'
20 0 20 40

EXISTING CAR WASH

BUILDING A

AUTO SERVICE

EXISTING

BUILDING B
3456NOTES
APN 419-150-047
LOT 27
APN 419-150-027
LOT 26
APN 419-150-026
LOT 25

DMA SURFACE TYPE AREA SUMMARY

BIO-RETENTION FACILITY

16.00'13.00'30.00'8.00'92.00'77.8"
8"12"45.5"9"12"8' MAX23.5" MINSF Total 2609.02
SF 1027.06Landscape (Self-retaining)
SF 1581.96Concrete or Asphalt (Drains to self-retaining) DMA 5
SF Total51198.29
SF 6187.45Landscape
SF 2970.73Roofs
SF42040.11Concrete or Asphalt
DMA 4
SF Total 5246.26
1225.82 SFLandscape
SF 3214.17Roofs
SF 806.28Concrete or Asphalt
DMA 3
SF Total 5068.80
SF 1039.10Landscape
SF 3214.33Roofs
SF 815.36Concrete or Asphalt
DMA 2
SF Total 1696.67
SF 1696.67Landscape (Self-treating)
DMA 1
PRINSCO HYDROSTOR HS180 CHAMBER SYSTEM

NOT A PART

NOT A PART
17-AUG-2022JOB 2019_23 PLOTTED:D:\MTH2\Engineering\2019_23 Beaumont\Civil\2019_23exb04_WQMP.dgn

IN THE CITY OF BEAUMONT, CALIFORNIA
HIGH SAND, INC.

HIGHLAND SPRINGS REMODEL AND DEVELOPMENT

WQMP SITE PLAN
GUIDANCE DOCUMENT, AND DOES NO RUN-ON TO THE PROPOSED PROJECT.

THE SANTA ANA REGION WATER QUALITY MANAGEMENT PLAN TECHNICAL THRESHOLDS LISTED PER TABLE 1-1 "PRIORITY DEVELOPMENT CATEGORIES" IN THE REDEVELOPMENT PROPOSED WITHIN LOT 27 DOES NOT MEET THE MINIMUM THE EXISTING DEVELOPED SITE WITHIN LOT 27 (APN 419-150-047) IS NOT A PART. 2.

CURB A MINIMUM OF 1" UNLESS OTHERWISE NOTED.

LANDSCAPE AREAS TO BE DEPRESSED BELOW ADJACENT HARDSCAPE OR TOP OF 1.

BMP GEO-LOCATIONS

INDICATES DMA BOUNDARY

INDICATES BUILDING ROOF

INDICATES LANDSCAPE

INDICATES FLOW DIRECTION
LEGEND

INDICATES PC CONCRETE PAVEMENT

INDICATES OVERFLOW INLET

INDICATES BIO-RETENTION FACILITY

INDICATES STORM DRAIN PIPE
6"
Dsoil PER PLAN
6' MIMINUM TOP WIDTH
4:1 SIDE SLOPE 4:1 SIDE SLOPE
THAT THE NITROGEN DOES NOT LEACH FROM THE MEDIA.

THE ORGANIC COMPONENT SHALL BE NITROGEN STABILIZED COMPOST, SUCH 3.

CLAY 5%-10%
SILT15%-20%
SAND70%-80%
THE RANGES BELOW:

THE MINERAL COMPONENT SHALL BE CLASS A SANDY LOAM TOPSOIL MEETING 2.

ORGANIC COMPONENTS BY VOLUME, DRUM MIXED PRIOR TO PLACEMENT.

ENGINEERED SOIL MEDIA SHALL BE COMPRISED OF 85% MINERAL AND 15% 1.

NOTES:
1'
--- ---SELF-RETAININGDMA 5/LANDSCAPE
2914.6 CF 2851.5 CFBIO-RETENTION FACILITYDMA 4/BR-4
338.4 CF 259.9 CFBIO-RETETNION FACILITYDMA 3/BR-3
301.6 CF 259.0 CFBIORETENTION FACILITYDMA 2/BR-2
--- ---SELF-TREATINGDMA 1/LANDSCAPE

PROVIDEDREQUIRED

DCV DCV LONGITUDE LATITUDE BMP DESCRIPTION DMA/ID HIGHLAND SPRINGS AVENUEWV WV
WV
WV
WV
WV
WV
VENT
EL
TS
SMH
WV
EMH
VENT
X
GM
GM
BF
EL
SCO
SCO
FDCPIV
WV
SMH XXXXPARKINGNOPARKINGNOPARKINGNOVANPOOL/EVCLEAN AIR/PARKINGNOPARKINGNOVANPOOL/EVCLEAN AIR/VANPOOL/EVCLEAN AIR/VANPOOL/EVCLEAN AIR/2590 2591
2591
259125912591 25912592
2592 2592259225922592
2592
2593
25932593
2593
2593
25 9
3 2
5 9
3 2593 25932594
25942595259325
9 3 25932594
2594
2594
25942594
25942594
25942594
2594
2595
2595
2595
2595
2595
2595 259125912592259225932593Page 325 of 1234

Page 1 of 5 ends

Retention/Detention Inspection & Maintenance
1717 16th St NE | Willmar, MN 56201 | 800.992.1725 | www.prinsco.com © Prinsco, Inc. 12/17
Introduction
Prinsco’s underground retention/detention systems provide a solution to effectively manage and store stormwater runoff utilizing a series of pipes and fittings. As the stormwater moves through the retention/ detention systems, sediment and debris will tend to settle out of the water and collect within the system.

This will require the system to be regularly inspected and cleaned in order for the system to perform as originally designed. Designing a system that is conducive to regular maintenance will allow the system to function efficiently and extend the service life.

System Accessories
A good maintenance program is just as important as proper design and installation. There are several components that can be incorporated into a system and can be used exclusively or in tandem to allow for ease of maintenance.

Risers – Risers are placed within a retention/detention system to provide manned access to key parts of the systems. Risers are typically 24” diameter or larger and are located on the laterals adjacent to the manifolds.

Cleanouts – Cleanouts are typically placed on the manifolds. Common sizes for cleanouts are 6- or 8- in diameter pipe. Cleanouts provide an access point for vacuum or water-jetting hoses used to clean the retention/detention system.

Pre-Treatment Device - The use of a pre-treatment unit is recommended for all retention or detention systems. A pre-treatment unit is designed to capture a majority of the sediment and debris before it is able to enter the retention/detention system. This will reduce the maintenance and cleaning requirements of the systems and reduce pollutants from reaching nearby waterways. Prinsco’s Stormwater Quality Unit (SWQU) is designed to remove debris collected in runoff including trash, sediment, oils and other suspended solids as shown in Figure 2. Prinsco’s SWQU is a cost-effective alternative to other units and removes 80 percent of total suspended solids, oil and grease.

Riser Cleanout
Figure 1: Riser and Cleanout Locations

Page 326 of 1234 ends

Page 2 of 5 ends

Retention/Detention Inspection & Maintenance

1717 16th St NE | Willmar, MN 56201 | 800.992.1725 | www.prinsco.com © Prinsco, Inc. 12/17
Retention/Detention System Maintenance
Maintaining a clean and obstruction-free retention/detention system is essential to ensuring the system performs as designed. Buildup of debris can obstruct flow through the laterals or block the entranceway of the outlet pipe in a retention or detention system that may result in ineffective. Additionally, surrounding areas may potentially run the risk of damage due to flooding or other similar issues.

Initial System Inspection
An initial inspection should be performed before the retention/detention system is put into operation. It is best to create an Inspection and Maintenance Log Sheet at this time. A sample of an Inspection and Maintenance Log Sheet can be found at the end of this technical note. Included with the log sheet should be a layout of the system with the invert elevations at the risers and cleanout locations, prior to sediment accumulation. Initial measurements can be taken with a stadia rod or other measurement techniques. These measurements will allow for inspection measurements to being taken from outside of the system, eliminating the need for manned entrance.

Inspection Frequency
Inspection frequency will vary based on the system design and requirements. A system inspection schedule should be developed for each individual system, with the industry standard being a minimum of once per year. After the inspection schedule is established for the system, it should be tracked on the Inspection and Maintenance Log Sheet.

Due to construction activities, more frequent inspections should be performed during the first year of operation. Construction sediment and debris loading can be minimized if the Stormwater Pollution Prevention Plan (SWPPP) plan for the construction site is followed. After the first year of operation the rate at which the retention or detention system collects soil/pollutants will be heavily dependent on the site activities. During winter months, in geographical areas where sand is applied to road surface, systems may see increased sediment loading. Other increased loading areas are present with vehicle or equipment wash-down areas.

During inspections, elevations of sediment height should be taken from each riser and cleanout. These elevations should be recorded on the Inspection and Maintenance Log Sheet to determine sediment high based on initial invert depth. Also during the inspection, personnel should be looking for blockages to inlet or outlet stubs. Inspection of the pre-treatment unit upstream of the system should always be inspected at this same time. Refer to the manufacturer’s recommendations for inspecting and maintaining the pre-treatment unit.

Figure 2: Prinsco’s Stormwater Quality Unit

Page 327 of 1234 ends

Page 3 of 5 ends

Retention/Detention Inspection & Maintenance

1717 16th St NE | Willmar, MN 56201 | 800.992.1725 | www.prinsco.com © Prinsco, Inc. 12/17
Maintenance Frequency
Cleaning frequency will vary for each. It is at the sole discretion of the inspector to determine if or when the system requires cleaning. The following are recommendations of when the system should be cleaned:
• If the system is experiencing an unusual amount of silt and soil build up • When the outlet stub becomes blocked or flow is impeded with sediment or debris • If the system does not drain to the lowest pipe elevation during dry conditions • If the system reaches a sediment height between 10 and 20 percent of the pipe diameter, the inspector should consider cleaning
If the system reaches a sediment height greater than 20 percent of the pipe diameter, the system should be clean at the soonest opportunity.

System Cleaning
There are typically two ways that a system is cleaned. The first, and most common method is done by using a high-
pressure water jet and a vacuum truck. The high-pressure nozzle with rear facing jets is attached to a hose and drug downstream, washing sediment and debris downstream with it.

The vacuum truck would then be located on the downstream end and remove the sediment and debris with its vacuum
hose. It should be noted that multiple passes of the water jet may be needed to clean the run, dependent on the amount of soil loading. The second method used is a manual method that is very labor intensive. This method should only be used with larger diameter retention or detention systems. Care needs to be taken to insure damage to the inside liner of the pipe does not occur when removing sediment and debris. Strategically placed risers and cleanouts will make this process as easy as possible.

Before the system is cleaned, the following considerations should be made:
• The system will be much easier to clean when there is little to no flow into the system and the system does not have any standing water. For this reason, system cleaning should be scheduled around dry weather.
• Before cleaning begins, all outlet stubs should be blocked off. If this is not done, sediment loading could back up or plug downstream pipelines adding to cleaning expenses. This is also done to prevent any of the debris or pollutants from washing into downstream waterways. • When beginning the cleaning process all upstream pipelines and pre-treatment units should be cleaned prior to starting on the retention or detention system. • When cleaning the retention or detention system, it is best to start at the highest elevation of the system and work towards the lowest elevation.
• Stationing the vacuum truck above the downstream manifold and jetting the debris from the laterals to the downstream manifold, provides an effective capture point for the vacuum line.

Figure 3: Vacuum Truck Removing
Sediment and Debris

Page 328 of 1234 ends

Page 329 of 1234 ends

Page 330 of 1234 ends

Inspection and Maintenance Guide

DRAINAG E P R O TECTION SY
S
T
E
MSA division of
Oldcastle Infrastructure
FLOGARD+PLUS®

CATCH BASIN INSERT FILTER

Page 331 of 1234 ends

SCOPE:

Federal, State and Local Clean Water Act regulations and those of insurance carriers require that stormwater filtration systems be maintained and serviced on a recurring basis. The intent of the regulations is to ensure that the systems, on a continuing basis, efficiently remove pollutants from stormwater runoff thereby preventing pollution of the nation’s water resources. These specifications apply to the FloGard+Plus® Catch Basin Insert Filter.

RECOMMENDED FREQUENCY OF SERVICE:

Drainage Protection Systems (DPS) recommends that installed FloGard+Plus Catch Basin Insert Filters be serviced on a recurring basis. Ultimately, the frequency depends on the amount of runoff, pollutant loading and interference from debris (leaves, vegetation, cans, paper, etc.); however, it is recommended that each installation be serviced a minimum of three times per year, with a change of filter medium once per year. DPS technicians are available to do an on-site evaluation, upon request.

RECOMMENDED TIMING OF SERVICE:

DPS guidelines for the timing of service are as follows:

1. For areas with a definite rainy season: Prior to, during and following the rainy season.

2. For areas subject to year-round rainfall: On a recurring basis (at least three times per year).

3. For areas with winter snow and summer rain: Prior to and just after the snow season and during the summer rain season.

4. For installed devices not subject to the elements (wash racks, parking garages, etc.): On a recurring basis (no less than three times per year).

SERVICE PROCEDURES:

1. The catch basin grate shall be removed and set to one side. The catch basin shall be visually inspected for defects and possible illegal dumping. If illegal dumping has occurred, the proper authorities and property owner representative shall be notified as soon as practicable.

2. Using an industrial vacuum, the collected materials shall be removed from the liner. (Note: DPS uses a truck-mounted vacuum for servicing FloGard+Plus catch basin inserts).

3. When all of the collected materials have been removed, the filter medium pouches shall be removed by unsnapping the tether from the D-ring and set to one side. The filter liner, gaskets, stainless steel frame and mounting brackets, etc., shall be inspected for continued serviceability. Minor damage or defects found shall be corrected on-the-spot and a notation made on the Maintenance Record.

More extensive deficiencies that affect the efficiency of the filter (torn liner, etc.), if approved by the customer representative, will be corrected and an invoice submitted to the representative along with the Maintenance Record.

4. The filter medium pouches shall be inspected for defects and continued serviceability and replaced as necessary, and the pouch tethers re-attached to the liner’s D-ring.

5. The grate shall be replaced.

REPLACEMENT AND DISPOSAL OF EXPOSED FILTER MEDIUM AND COLLECTED DEBRIS The frequency of filter medium exchange will be in accordance with the existing DPS-Customer Maintenance Contract. DPS recommends that the medium be changed at least once per year. During the appropriate service, or if so determined by the service technician during a non-scheduled service, the filter medium will be replaced with new material. Once the exposed pouches and debris have been removed, DPS has possession and must dispose of it in accordance with local, state and federal agency requirements.

DPS also has the capability of servicing all manner of storm drain filters, catch basin inserts and catch basins without inserts, underground oil/water separators, stormwater interceptors and other such devices.

All DPS personnel are highly qualified technicians and are confined-space trained and certified. Call us at (888) 950-8826 for further information and assistance.
2Page 332 of 1234

FLOGARD+PLUS®

CATCH BASIN INSERT FILTER

BUILDING

STRUCTURES

OUR MARKETS

TRANSPORTATION
WATER

ENERGYCOMMUNICATIONS
February 2019 v.1
www.oldcastleinfrastructure.com
800-579-8819

Page 333 of 1234 ends

Replacement & Repair
Instruction Manual
FLOGARD +PLUS®

Page 334 of 1234 ends

1 FloGard Plus Replacement and Repair
Parts of the FloGard Plus Inlet Filter-

1. FloGard Stainless Steel Support Frame

2. Fossil Rock Absorbent Pouches

3. Liner

4. GeoGrid Support Basket & Cable
* Grate and Basin NOT INCLUDED
Disassembly:

1.Clear FloGard of any existing debris by hand or vacuum.

2.Unclip and remove the Fossil Rock pouches from the inside Liner.

3.Lift the FloGard from the catch basin.

4.Using a slotted screw driver, carefully pry open the metal tabs holding the GeoGrid and Cable in place. Separate the GeoGrid and Liner from the FloGard frame.

5.Unclip the Liner from the inside of the GeoGrid. If you are reusing the Liner, rinse thoroughly with water and inspect for tears. (If torn, mend with stainless steel wire or replace the Liner).

6.Rinse and inspect the GeoGrid Basket and the reinforcing cable. (If torn, mend with stainless steel wire or replace the GeoGrid).

7.Rinse and inspect the Stainless Steel FloGard frame.

Reassembly:

1.Fully expand the GeoGrid Basket and orient to the FloGard frame.

Hook cable and GeoGrid to the FloGard frame metal tabs and close the tabs using slotted screwdriver. Move around the FloGard until all tabs are closed and GeoGrid is secured to the Frame.

2.Expand and orient the Liner, locating the clips at each corner and side.

Push the Liner through the center of the FloGard frame and secure the clips to the GeoGrid Basket close to the top support cable. Push the Liner to expand inside of the basket.

3.Clip new Fossil Rock Rubberizer pouches to the inside of the Liner.

4.Lower FloGard back into the basin, replace grate.
1 2
3 4

Page 335 of 1234 ends

www.oldcastlestormwater.com
800-579-8819

BUILDING

STRUCTURES

OUR MARKETS

TRANSPORTATION
WATER

ENERGYCOMMUNICATIONS
FLOGARD +PLUS®
June 2018 v.1Page 336 of 1234

- 38 -

Appendix 10: Educational Materials
BMP Fact Sheets, Maintenance Guidelines and Other End-User BMP Information

Page 337 of 1234 ends

Non-Stormwater Discharges SC-10
September 2014 California Stormwater BMP Handbook
Industrial and Commercial
www.casqa.org
1 of 10
Description
Non-stormwater discharges (NSWDs) are
flows that do not consist entirely of
stormwater. Some non-stormwater
discharges do not include pollutants and
may be discharged to the storm drain if local
regulations allow. These include
uncontaminated groundwater and natural
springs. There are also some non-
stormwater discharges that typically do not
contain pollutants and may be discharged to
the storm drain with conditions. These
include: potable water sources, fire hydrant
flushing, air conditioner condensate,
landscape irrigation drainage and landscape
watering, emergency firefighting, etc. as
discussed in Section 2.

However there are certain non-stormwater
discharges that pose an environmental
concern. These discharges may originate
from illegal dumping of industrial material or wastes and illegal connections such as Objectives
n Cover
n Contain
n Educate
n Reduce/Minimize
n Product Substitution
Targeted Constituents
Sediment
Nutrients ü
Trash
Metals ü
Bacteria ü
Oil and Grease ü
Organics ü
Minimum BMPs Covered
Good Housekeeping ü
Preventative
Maintenance
Spill and Leak
internal floor drains, appliances, industrial
processes, sinks, and toilets that are illegally
connected to the nearby storm drainage
system through on-site drainage and piping.

These unauthorized discharges (examples of
which may include: process waste waters,
cooling waters, wash waters, and sanitary
wastewater) can carry substances such as
paint, oil, fuel and other automotive fluids,
chemicals and other pollutants into storm
drains.

Non-stormwater discharges will need to be
addressed through a combination of
detection and elimination. The ultimate
goal is to effectively eliminate unauthorized
non-stormwater discharges to the
stormwater drainage system through
implementation of measures to detect,
correct, and enforce against illicit
connections and illegal discharges of
Prevention and ü
Response
Material Handling &
Waste Management
Erosion and
Sediment Controls
Employee Training
Program
Quality Assurance
Record Keeping
ü
ü

Page 338 of 1234 ends

Non-Stormwater Discharges SC-10
September 2014 California Stormwater BMP Handbook
Industrial and Commercial
www.casqa.org
2 of 10
pollutants on streets and into the storm drain system and downstream water bodies.

Approach
Initially the Discharger must make an assessment of non-stormwater discharges to determine which types must be eliminated or addressed through BMPs. The focus of the following approach is the elimination of unauthorized non-stormwater discharges. See other BMP Fact Sheets for activity-specific pollution prevention procedures.

General Pollution Prevention Protocols
o Implement waste management controls described in SC-34 Waste Handling and Disposal.
o Develop clear protocols and lines of communication for effectively prohibiting non- stormwater discharges, especially those that are not classified as hazardous. These are often not responded to as effectively as they need to be. o Stencil or demarcate storm drains, where applicable, to prevent illegal disposal of pollutants. Storm drain inlets should have messages such as “Dump No Waste Drains to Stream” or similar stenciled or demarcated next to them to warn against ignorant or unintentional dumping of pollutants into the storm drainage system. o Manage and control sources of water such as hose bibs, faucets, wash racks, irrigation heads, etc. Identify hoses and faucets in the SWPPP, and post signage for appropriate use.

Non-Stormwater Discharge Investigation Protocols
Identifying the sources of non-stormwater discharges requires the Discharger to conduct an investigation of the facility at regular intervals. There are several categories of non- stormwater discharges:
o Visible, easily identifiable discharges, typically generated as surface runoff, such as uncontained surface runoff from vehicle or equipment washing; and o Non-visible, (e.g., subsurface) discharges into the site drainage system through a variety of pathways that are not obvious.

The approach to detecting and eliminating non-stormwater discharges will vary considerably, as discussed below:

Visible and identifiable discharges
o Conduct routine inspections of the facilities and of each major activity area and identify visible evidence of unauthorized non-stormwater discharges. This may include:
ü Visual observations of actual discharges occurring;

Page 339 of 1234 ends

Non-Stormwater Discharges SC-10
September 2014 California Stormwater BMP Handbook
Industrial and Commercial
www.casqa.org
3 of 10
ü Evidence of surface staining, discoloring etc. that indicates that discharges have occurred;
ü Pools of water in low lying areas when a rain event has not occurred; and ü Discussions with operations personnel to understand practices that may lead to unauthorized discharges.
o If evidence of non-stormwater discharges is discovered:
ü Document the location and circumstances using Worksheets 5 and 6 (Section 2 of the manual), including digital photos;
ü Identify and implement any quick remedy or corrective action (e.g., moving uncovered containers inside or to a proper location); and ü Develop a plan to eliminate the discharge. Consult the appropriate activity- specific BMP Fact Sheet for alternative approaches to manage and eliminate the discharge.
o Consult the appropriate activity-specific BMP Fact Sheet for alternative approaches to manage and eliminate the discharge. Make sure the facility SWPPP is up-to-date and includes applicable BMPs to address the non-stormwater discharge.

Other Illegal Discharges (Non visible)
Illicit Connections
o Locate discharges from the industrial storm drainage system to the municipal storm drain system through review of “as-built” piping schematics. o Isolate problem areas and plug illicit discharge points. o Locate and evaluate discharges to the storm drain system. o Visual Inspection and Inventory:
ü Inventory and inspect each discharge point during dry weather. ü Keep in mind that drainage from a storm event can continue for a day or two following the end of a storm and groundwater may infiltrate the underground stormwater collection system.
ü Non-stormwater discharges are often intermittent and may require periodic inspections.

Review Infield Piping
o A review of the “as-built” piping schematic is a way to determine if there are any connections to the stormwater collection system.

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o Inspect the path of loading/unloading area drain inlets and floor drains in older buildings.
o Never assume storm drains are connected to the sanitary sewer system.

Monitoring for investigation/detection of illegal discharges o If a suspected illegal or unknown discharge is detected, monitoring of the discharge may help identify the content and/or suggest the source. This may be done with a field screening analysis, flow meter measurements, or by collecting a sample for laboratory analysis. Section 5 and Appendix D describe the necessary field equipment and procedures for field investigations.
o Investigative monitoring may be conducted over time. For example if, a discharge is intermittent, then monitoring might be conducted to determine the timing of the discharge to determine the source.
o Investigative monitoring may be conducted over a spatial area. For example, if a discharge is observed in a pipe, then monitoring might be conducted at accessible upstream locations in order to pinpoint the source of the discharge. o Generally, investigative monitoring requiring collection of samples and submittal for lab analysis requires proper planning and specially trained staff.

Smoke Testing
Smoke testing of wastewater and stormwater collection systems is used to detect connections between the two piping systems. Smoke testing is generally performed at a downstream location and the smoke is forced upstream using blowers to create positive pressure. The advantage to smoke testing is that it can potentially identify multiple potential discharge sources at once.
o Smoke testing uses a harmless, non-toxic smoke cartridges developed specifically for this purpose.
o Smoke testing requires specialized equipment (e.g., cartridges, blowers) and is generally only appropriate for specially trained staff. o A Standard Operating Procedure (SOP) for smoke testing is highly desirable. The SOP should address the following elements:
ü Proper planning and notification of nearby residents and emergency services is necessary since introducing smoke into the system may result in false alarms; ü During dry weather, the stormwater collection system is filled with smoke and then traced back to sources;

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ü Temporary isolation of segments of pipe using sand bags is often needed to force the smoke into leaking pipes; and
ü The appearance of smoke in a waste vent pipe, at a sewer manhole, or even the base of a toilet indicates that there may be a connection between the sanitary and storm water systems.
o Most municipal wastewater agencies will have necessary staff and equipment to conduct smoke testing and they should be contacted if cross connections with the sanitary sewer are suspected. See SC-44 Drainage System Maintenance for more information.

Dye Testing
o Dye testing is typically performed when there is a suspected specific pollutant source and location (i.e., leaking sanitary sewer) and there is evidence of dry weather flows in the stormwater collection system.
o Dye is released at a probable upstream source location, either the facility’s sanitary or process wastewater system. The dye must be released with a sufficient volume of water to flush the system.
o Operators then visually examine the downstream discharge points from the stormwater collection system for the presence of the dye. o Dye testing can be performed informally using commercially available products in order to conduct an initial investigation for fairly obvious cross-connections. o More detailed dye testing should be performed by properly trained staff and follow SOPs. Specialized equipment such as fluorometers may be necessary to detect low concentrations of dye.
o Most municipal wastewater agencies will have necessary staff and equipment to conduct dye testing and they should be contacted if cross connections with the sanitary sewer are suspected.

TV Inspection of Drainage System
o Closed Circuit Television (CCTV) can be employed to visually identify illicit connections to the industrial storm drainage system. Two types of CCTV systems are available: (1) a small specially designed camera that can be manually pushed on a stiff cable through storm drains to observe the interior of the piping, or (2) a larger remote operated video camera on treads or wheels that can be guided through storm drains to view the interior of the pipe.
o CCTV systems often include a high-pressure water jet and camera on a flexible cable.

The water jet cleans debris and biofilm off the inside of pipes so the camera can take video images of the pipe condition.

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o CCTV units can detect large cracks and other defects such as offsets in pipe ends caused by root intrusions or shifting substrate.
o CCTV can also be used to detect dye introduced into the sanitary sewer. o CCTV inspections require specialized equipment and properly trained staff and are generally best left to specialized contractors or municipal public works staff.

Illegal Dumping
o Substances illegally dumped on streets and into the storm drain systems and creeks may include paints, used oil and other automotive fluids, construction debris, chemicals, fresh concrete, leaves, grass clippings, and pet wastes. These wastes can cause stormwater and receiving water quality problems as well as clog the storm drain system itself.
o Establish a system for tracking incidents. The system should be designed to identify the following:
ü Illegal dumping hot spots;
ü Types and quantities (in some cases) of wastes;
ü Patterns in time of occurrence (time of day/night, month, or year); ü Mode of dumping (abandoned containers, “midnight dumping” from moving vehicles, direct dumping of materials, accidents/spills); ü An anonymous tip/reporting mechanism; and
ü Evidence of responsible parties (e.g., tagging, encampments, etc.). o One of the keys to success of reducing or eliminating illegal dumping is increasing the number of people at the facility who are aware of the problem and who have the tools to at least identify the incident, if not correct it. Therefore, train field staff to recognize and report the incidents.

Once a site has been cleaned:
o Post “No Dumping” signs with a phone number for reporting dumping and disposal. o Landscaping and beautification efforts of hot spots may also discourage future dumping, as well as provide open space and increase property values. o Lighting or barriers may also be needed to discourage future dumping. o See fact sheet SC-11 Spill Prevention, Control, and Cleanup.

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Inspection
o Regularly inspect and clean up hot spots and other storm drainage areas where illegal dumping and disposal occurs.
o Conduct field investigations of the industrial storm drain system for potential sources of non-stormwater discharges.
o Pro-actively conduct investigations of high priority areas. Based on historical data, prioritize specific geographic areas and/or incident type for pro-active investigations.

Spill and Leak Prevention and Response
o On paved surfaces, clean up spills with as little water as possible. Use a rag for small spills, a damp mop for general cleanup, and absorbent material for larger spills. If the spilled material is hazardous, then the used cleanup materials are also hazardous and must be sent to a certified laundry (rags) or disposed of as hazardous waste. o Never hose down or bury dry material spills. Sweep up the material and dispose of properly.
o Use adsorbent materials on small spills rather than hosing down the spill. Remove the adsorbent materials promptly and dispose of properly. o For larger spills, a private spill cleanup company or Hazmat team may be necessary. o See SC-11 Spill Prevention Control and Cleanup.

Employee Training Program
o Training of technical staff in identifying and documenting illegal dumping incidents is required. The frequency of training must be presented in the SWPPP, and depends on site-specific industrial materials and activities.
o Consider posting a quick reference table near storm drains to reinforce training. o Train employees to identify non-stormwater discharges and report discharges to the appropriate departments.
o Educate employees about spill prevention and cleanup. o Well-trained employees can reduce human errors that lead to accidental releases or spills. The employee should have the tools and knowledge to immediately begin cleaning up a spill should one occur. Employees should be familiar with the Spill Prevention Control and Countermeasure Plan. Employees should be able to identify work/jobs with high potential for spills and suggest methods to reduce possibility. o Determine and implement appropriate outreach efforts to reduce non-permissible non-stormwater discharges.

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o Conduct spill response drills annually (if no events occurred) in order to evaluate the effectiveness of the plan.
o When a responsible party is identified, educate the party on the impacts of his or her actions.

Quality Assurance and Record Keeping
Performance Evaluation
o Annually review internal investigation results; assess whether goals were met and what changes or improvements are necessary.
o Obtain feedback from personnel assigned to respond to, or inspect for, illicit connections and illegal dumping incidents.
o Develop document and data management procedures.
o A database is useful for defining and tracking the magnitude and location of the problem.
o Report prohibited non-stormwater discharges observed during the course of normal daily activities so they can be investigated, contained, and cleaned up or eliminated. o Document that non-stormwater discharges have been eliminated by recording tests performed, methods used, dates of testing, and any on-site drainage points observed. o Annually document and report the results of the program. o Maintain documentation of illicit connection and illegal dumping incidents, including significant conditionally exempt discharges that are not properly managed. o Document training activities.

Potential Limitations and Work-Arounds
Some facilities may have space constraints, limited staffing and time limitations that may preclude implementation of BMPs. Provided below are typical limitations and recommended “work-arounds.”
o Many facilities do not have accurate, up-to-date ‘as-built’ plans or drawings which may be necessary in order to conduct non-stormwater discharge assessments. ü Online tools such as Google Earth™ can provide an aerial view of the facility and may be useful in understanding drainage patterns and potential sources of non- stormwater discharges
ü Local municipal jurisdictions may have useful drainage systems maps.

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o Video surveillance cameras are commonly used to secure the perimeter of industrial facilities against break-ins and theft. These surveillance systems may also be useful for capturing illegal dumping activities. Minor, temporary adjustments to the field of view of existing surveillance camera systems to target known or suspected problem areas may be a cost-effective way of capturing illegal dumping activities and identifying the perpetrators.

Potential Capital Facility Costs and Operation & Maintenance Requirements
Facilities
o Capital facility cost requirements may be minimal unless cross-connections to storm drains are detected.
o Indoor floor drains may require re-plumbing if cross-connections are detected. o Leaky sanitary sewers will require repair or replacement which can have significant costs depending on the size and industrial activity at the facility.

Maintenance (including administrative and staffing)
o The primary effort is for staff time and depends on how aggressively a program is implemented.
o Costs for containment, and disposal of any leak or discharge is borne by the Discharger.
o Illicit connections can be difficult to locate especially if there is groundwater infiltration.
o Illegal dumping and illicit connection violations requires technical staff to detect and investigate them.

Supplemental Information
Permit Requirements
The IGP authorizes certain Non-Storm Water Discharges (NSWDs) provided BMPs are included in the SWPPP and implemented to:
o Reduce or prevent the contact of authorized NSWDs with materials or equipment that are potential sources of pollutants;
o Reduce, to the extent practicable, the flow or volume of authorized NSWDs; o Ensure that authorized NSWDs do not contain quantities of pollutants that cause or contribute to an exceedance of a water quality standards (WQS); and,

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o Reduce or prevent discharges of pollutants in authorized NSWDs in a manner that reflects best industry practice considering technological availability and economic practicability and achievability.”
References and Resources
Center for Watershed Protection, 2004. Illicit Discharge Detection and Elimination: A Guidance Manual for Program Development and Technical Assessments, EPA Cooperative Agreement X-82907801-0.

Dublin San Ramon Sanitation District. http://www.dsrsd.com/wwrw/smoketest.html .

Orange County Stormwater Program, Best Management Practices for Industrial/Commercial Business Activities. Available online at:
http://ocwatersheds.com/documents/bmp/industrialcommercialbusinessesactivities .

Sacramento Stormwater Management Program, Best Management Practices for Industrial Storm Water Pollution Control, Available online at:
http://www.msa.saccounty.net/sactostormwater/documents/guides/industrial-BMP- manual.pdf.

Santa Clara Valley Urban Runoff Pollution Prevention Program. http://www.scvurppp.org .

Southern California Coastal Water Research Project, 2013. The California Microbial Source Identification Manual: A Tiered Approach to Identifying Fecal Pollution Sources to Beaches, Technical Report 804.

The Storm Water Managers Resource Center, http://www.stormwatercenter.net/ .

US EPA. National Pollutant Discharge Elimination System. Available online at:
http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm?action=factsheet_res ults&view=specific&bmp=111.

WEF Press Alexandria, Virginia, 2009.Existing Sewer Evaluation and Rehabilitation:

WEF Manual of Practice No. FD-6 ASCE/EWRI Manuals and Reports on Engineering Practice No. 62, Third Edition.

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Description
Many activities that occur at an industrial or
commercial site have the potential to cause
accidental spills. Preparation for accidental
spills, with proper training and reporting
systems implemented, can minimize the
discharge of pollutants to the environment.

Spills and leaks are one of the largest
contributors of stormwater pollutants. Spill
prevention and control plans are applicable to
any site at which hazardous materials are stored
or used. An effective plan should have spill
prevention and response procedures that
identify hazardous material storage areas,
specify material handling procedures, describe
spill response procedures, and provide locations
of spill clean-up equipment and materials. The
plan should take steps to identify and
characterize potential spills, eliminate and
reduce spill potential, respond to spills when
they occur in an effort to prevent pollutants
from entering the stormwater drainage system,
Objectives
n Cover
n Contain
n Educate
n Reduce/Minimize
n Product Substitution
Targeted Constituents
Sediment
Nutrients
Trash
Metals ü
Bacteria
Oil and Grease ü
Organics ü
Minimum BMPs Covered
Good Housekeeping
Preventative
Maintenance
Spill and Leak
and train personnel to prevent and control
future spills. An adequate supply of spill clean-
up materials must be maintained onsite.

Approach
General Pollution Prevention Protocols
o Develop procedures to prevent/mitigate
spills to storm drain systems.
o Develop and standardize reporting
procedures, containment, storage, and
disposal activities, documentation, and
follow-up procedures.
o Establish procedures and/or controls to
minimize spills and leaks. The procedures
should address:
ü Description of the facility, owner and
address, activities, chemicals, and
quantities present;
Prevention and ü
Response
Material Handling &
Waste Management
Erosion and Sediment
Controls Employee Training
Program ü
Quality Assurance
Record Keeping ü

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ü Facility map of the locations of industrial materials; ü Notification and evacuation procedures;
ü Cleanup instructions;
ü Identification of responsible departments; and
ü Identify key spill response personnel.
o Recycle, reclaim, or reuse materials whenever possible. This will reduce the amount of process materials that are brought into the facility.

Spill and Leak Prevention and Response
Spill Prevention
o Develop procedures to prevent/mitigate spills to storm drain systems. Develop and standardize reporting procedures, containment, storage, and disposal activities, documentation, and follow-up procedures.
o If illegal dumping is observed at the facility:
ü Post “No Dumping” signs with a phone number for reporting illegal dumping and disposal. Signs should also indicate fines and penalties applicable for illegal dumping.
ü Landscaping and beautification efforts may also discourage illegal dumping. ü Bright lighting and/or entrance barriers may also be needed to discourage illegal dumping.
o Store and contain liquid materials in such a manner that if the container is ruptured, the contents will not discharge, flow, or be washed into the storm drainage system, surface waters, or groundwater.
o If the liquid is oil, gas, or other material that separates from and floats on water, install a spill control device (such as a tee section) in the catch basins that collects runoff from the storage tank area.

Preventative Maintenance
o Place drip pans or absorbent materials beneath all mounted taps, and at all potential drip and spill locations during filling and unloading of tanks. Any collected liquids or soiled absorbent materials must be reused/recycled or properly disposed. o Store and maintain appropriate spill cleanup materials in a location known to all near the tank storage area; and ensure that employees are familiar with the site’s spill control plan and/or proper spill cleanup procedures.

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o Sweep and clean the storage area monthly if it is paved, do not hose down the area to a storm drain.

o Check tanks (and any containment sumps) daily for leaks and spills. Replace tanks that are leaking, corroded, or otherwise deteriorating with tanks in good condition.

Collect all spilled liquids and properly dispose of them.

o Label all containers according to their contents (e.g., solvent, gasoline).

o Label hazardous substances regarding the potential hazard (corrosive, radioactive, flammable, explosive, poisonous).

o Prominently display required labels on transported hazardous and toxic materials (per US DOT regulations).

o Identify key spill response personnel.

Spill Response
o Clean up leaks and spills immediately.

o Place a stockpile of spill cleanup materials where it will be readily accessible (e.g., near storage and maintenance areas).

o On paved surfaces, clean up spills with as little water as possible.

ü Use a rag for small spills, a damp mop for general cleanup, and absorbent material for larger spills.

ü If the spilled material is hazardous, then the used cleanup materials are also hazardous and must be sent to a certified laundry (rags) or disposed of as hazardous waste.

ü If possible use physical methods for the cleanup of dry chemicals (e.g., brooms, shovels, sweepers, or vacuums).

o Never hose down or bury dry material spills. Sweep up the material and dispose of properly.

o Chemical cleanups of material can be achieved with the use of adsorbents, gels, and foams. Use adsorbent materials on small spills rather than hosing down the spill.

Remove the adsorbent materials promptly and dispose of properly.

o For larger spills, a private spill cleanup company or Hazmat team may be necessary.

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Reporting
o Report spills that pose an immediate threat to human health or the environment to the Regional Water Quality Control Board or local authority as location regulations dictate.

o Federal regulations require that any oil spill into a water body or onto an adjoining shoreline be reported to the National Response Center (NRC) at 800-424-8802 (24 hour).

o Report spills to 911 for dispatch and clean-up assistance when needed. Do not contact fire agencies directly.

o Establish a system for tracking incidents. The system should be designed to identify the following:

ü Types and quantities (in some cases) of wastes;

ü Patterns in time of occurrence (time of day/night, month, or year);

ü Mode of dumping (abandoned containers, “midnight dumping” from moving vehicles, direct dumping of materials, accidents/spills);

ü Clean-up procedures; and

ü Responsible parties.

Employee Training Program
o Educate employees about spill prevention and cleanup.

o Well-trained employees can reduce human errors that lead to accidental releases or spills:

ü The employee should have the tools and knowledge to immediately begin cleaning up a spill should one occur; and

ü Employees should be familiar with the Spill Prevention Control and Countermeasure Plan.

o Employees should be educated about aboveground storage tank requirements.

Employees responsible for aboveground storage tanks and liquid transfers should be thoroughly familiar with the Spill Prevention Control and Countermeasure Plan and the plan should be readily available.

o Train employees to recognize and report illegal dumping incidents.

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Other Considerations (Limitations and Regulations)
o State regulations exist for facilities with a storage capacity of 10,000 gallons or more of petroleum to prepare a Spill Prevention Control and Countermeasure (SPCC) Plan (Health & Safety Code Chapter 6.67).

o State regulations also exist for storage of hazardous materials (Health & Safety Code Chapter 6.95), including the preparation of area and business plans for emergency response to the releases or threatened releases.

o Consider requiring smaller secondary containment areas (less than 200 sq. ft.) to be connected to the sanitary sewer, prohibiting any hard connections to the storm drain.

Requirements
Costs (including capital and operation & maintenance)
o Will vary depending on the size of the facility and the necessary controls.

o Prevention of leaks and spills is inexpensive. Treatment and/or disposal of contaminated soil or water can be quite expensive.

Maintenance (including administrative and staffing)
o Develop spill prevention and control plan, provide and document training, conduct inspections of material storage areas, and supply spill kits.

o Extra time is needed to properly handle and dispose of spills, which results in increased labor costs.

Supplemental Information
Further Detail of the BMP
Reporting
Record keeping and internal reporting represent good operating practices because they can increase the efficiency of the facility and the effectiveness of BMPs. A good record keeping system helps the facility minimize incident recurrence, correctly respond with appropriate cleanup activities, and comply with legal requirements. A record keeping and reporting system should be set up for documenting spills, leaks, and other discharges, including discharges of hazardous substances in reportable quantities.

Incident records describe the quality and quantity of non-stormwater discharges to the storm sewer. These records should contain the following information:

o Date and time of the incident;

o Weather conditions;

o Duration of the spill/leak/discharge;

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o Cause of the spill/leak/discharge;

o Response procedures implemented;

o Persons notified; and

o Environmental problems associated with the spill/leak/discharge.

Separate record keeping systems should be established to document housekeeping and preventive maintenance inspections, and training activities. All housekeeping and preventive maintenance inspections should be documented. Inspection documentation should contain the following information:

o Date and time the inspection was performed;

o Name of the inspector;

o Items inspected;

o Problems noted;

o Corrective action required; and

o Date corrective action was taken.

Other means to document and record inspection results are field notes, timed and dated photographs, videotapes, and drawings and maps.

Aboveground Tank Leak and Spill Control
Accidental releases of materials from aboveground liquid storage tanks present the potential for contaminating stormwater with many different pollutants. Materials spilled, leaked, or lost from tanks may accumulate in soils or on impervious surfaces and be carried away by stormwater runoff.

The most common causes of unintentional releases are:

o Installation problems;

o Failure of piping systems (pipes, pumps, flanges, couplings, hoses, and valves);

o External corrosion and structural failure;

o Spills and overfills due to operator error; and

o Leaks during pumping of liquids or gases from truck or rail car to a storage tank or vice versa.

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Storage of reactive, ignitable, or flammable liquids should comply with the Uniform Fire Code and the National Electric Code. Practices listed below should be employed to enhance the code requirements:

o Tanks should be placed in a designated area.

o Tanks located in areas where firearms are discharged should be encapsulated in concrete or the equivalent.

o Designated areas should be impervious and paved with Portland cement concrete, free of cracks and gaps, in order to contain leaks and spills.

o Liquid materials should be stored in UL approved double walled tanks or surrounded by a curb or dike to provide the volume to contain 10 percent of the volume of all of the containers or 110 percent of the volume of the largest container, whichever is greater. The area inside the curb should slope to a drain.

o For used oil or dangerous waste, a dead-end sump should be installed in the drain.

o All other liquids should be drained to the sanitary sewer if available. The drain must have a positive control such as a lock, valve, or plug to prevent release of contaminated liquids.

o Accumulated stormwater in petroleum storage areas should be passed through an oil/water separator.

Maintenance is critical to preventing leaks and spills. Conduct routine inspections and:

o Check for external corrosion and structural failure.

o Check for spills and overfills due to operator error.

o Check for failure of piping system (pipes, pumps, flanges, coupling, hoses, and valves).

o Check for leaks or spills during pumping of liquids or gases from truck or rail car to a storage facility or vice versa.

o Visually inspect new tank or container installation for loose fittings, poor welding, and improper or poorly fitted gaskets.

o Inspect tank foundations, connections, coatings, and tank walls and piping system.

Look for corrosion, leaks, cracks, scratches, and other physical damage that may weaken the tank or container system.

o Frequently relocate accumulated stormwater during the wet season.

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o Periodically conduct integrity testing by a qualified professional.

Vehicle Leak and Spill Control
Major spills on roadways and other public areas are generally handled by highly trained Hazmat teams from local fire departments or environmental health departments. The measures listed below pertain to leaks and smaller spills at vehicle maintenance shops.

In addition to implementing the spill prevention, control, and clean up practices above, use the following measures related to specific activities:

Vehicle and Equipment Maintenance
o Perform all vehicle fluid removal or changing inside or under cover to prevent the run-on of stormwater and the runoff of spills.

o Regularly inspect vehicles and equipment for leaks, and repair immediately.

o Check incoming vehicles and equipment (including delivery trucks, and employee and subcontractor vehicles) for leaking oil and fluids. Do not allow leaking vehicles or equipment onsite.

o Always use secondary containment, such as a drain pan or drop cloth, to catch spills or leaks when removing or changing fluids.

o Immediately drain all fluids from wrecked vehicles.

o Store wrecked vehicles or damaged equipment under cover.

o Place drip pans or absorbent materials under heavy equipment when not in use.

o Use absorbent materials on small spills rather than hosing down the spill.

o Remove the adsorbent materials promptly and dispose of properly.

o Promptly transfer used fluids to the proper waste or recycling drums. Don’t leave full drip pans or other open containers lying around.

o Oil filters disposed of in trashcans or dumpsters can leak oil and contaminate stormwater. Place the oil filter in a funnel over a waste oil recycling drum to drain excess oil before disposal. Oil filters can also be recycled. Ask your oil supplier or recycler about recycling oil filters.

o Store cracked batteries in a non-leaking secondary container. Do this with all cracked batteries, even if you think all the acid has drained out. If you drop a battery, treat it as if it is cracked. Put it into the containment area until you are sure it is not leaking.

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Vehicle and Equipment Fueling
o Design the fueling area to prevent the run-on of stormwater and the runoff of spills:

Cover fueling area if possible.

Use a perimeter drain or slope pavement inward with drainage to a sump.

Pave fueling area with concrete rather than asphalt.
o If dead-end sump is not used to collect spills, install an oil/water separator.

o Install vapor recovery nozzles to help control drips as well as air pollution.

o Discourage “topping-off’ of fuel tanks.

o Use secondary containment when transferring fuel from the tank truck to the fuel tank.

o Use absorbent materials on small spills and general cleaning rather than hosing down the area. Remove the absorbent materials promptly.

o Carry out all Federal and State requirements regarding underground storage tanks, or install above ground tanks.

o Do not use mobile fueling of mobile industrial equipment around the facility; rather, transport the equipment to designated fueling areas.

o Keep your Spill Prevention Control and Countermeasure (SPCC) Plan up-to-date.

o Train employees in proper fueling and cleanup procedures.

Industrial Spill Prevention Response
For the purposes of developing a spill prevention and response program to meet the stormwater regulations, facility managers should use information provided in this fact sheet and the spill prevention/response portions of the fact sheets in this handbook, for specific activities.

The program should:

o Integrate with existing emergency response/hazardous materials programs (e.g., Fire Department).

o Develop procedures to prevent/mitigate spills to storm drain systems.

o Identify responsible departments.

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o Develop and standardize reporting procedures, containment, storage, and disposal activities, documentation, and follow-up procedures.

o Address spills at municipal facilities, as well as public areas.

o Provide training concerning spill prevention, response and cleanup to all appropriate personnel.

References and Resources
California’s Nonpoint Source Program Plan. http://www.swrcb.ca.gov/nps/index.html .

Clark County Storm Water Pollution Control Manual. Available online at:
http://www.co.clark.wa.us/pubworks/bmpman.pdf .

King County Storm Water Pollution Control Manual. Available online at:
http://dnr.metrokc.gov/wlr/dss/spcm.htm .

Santa Clara Valley Urban Runoff Pollution Prevention Program. http://www.scvurppp.org .

The Stormwater Managers Resource Center. http://www.stormwatercenter.net/ .

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Good Housekeeping ü
Preventative Maintenance
Spill and Leak Prevention
and Response
Material Handling &
Waste Management
Erosion and Sediment
Controls
Employee Training
Program
Quality Assurance Record
Keeping
ü
ü

ü

Description
Objectives The loading/unloading of materials usually
takes place outside on docks or terminals;
therefore, materials spilled, leaked, or lost
during loading/unloading may collect in the
soil or on other surfaces and have the
potential to be carried away by wind,
stormwater runoff or when the area is
cleaned. Additionally, rainfall may wash
pollutants from machinery used to unload or
move materials. Implementation of the
following protocols will prevent or reduce the
discharge of pollutants to stormwater from
outdoor loading/unloading of materials.

Approach
Reduce potential for pollutant discharge
through source control pollution prevention
and BMP implementation. Successful
implementation depends on effective training
of employees on applicable BMPs and general
pollution prevention strategies and
objectives.

General Pollution Prevention
Protocols

o Park tank trucks or delivery vehicles in
designated areas so that spills or leaks
can be contained.

o Limit exposure of material to rainfall
whenever possible.

o Prevent stormwater run-on.

o Check equipment regularly for leaks.

Good Housekeeping

o Develop an operations plan that
describes procedures for loading
and/or unloading.

o Conduct loading and unloading in dry
weather if possible.
n Cover
n Contain
n Educate
n Reduce/Minimize
n Product Substitution

Targeted Constituents

Sediment ü

Nutrients ü

Trash

Metals ü

Bacteria

Oil and Grease ü

Organics ü

Minimum BMPs Covered

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o Cover designated loading/unloading areas to reduce exposure of materials to rain.

o Consider placing a seal or door skirt between delivery vehicles and building to prevent exposure to rain.

o Design loading/unloading area to prevent stormwater run-on, which would include grading or berming the area, and position roof downspouts so they direct stormwater away from the loading/unloading areas.

o Have employees load and unload all materials and equipment in covered areas such as building overhangs at loading docks if feasible.

o Load/unload only at designated loading areas.

o Use drip pans underneath hose and pipe connections and other leak-prone spots during liquid transfer operations, and when making and breaking connections.

Several drip pans should be stored in a covered location near the liquid transfer area so that they are always available, yet protected from precipitation when not in use. Drip pans can be made specifically for railroad tracks. Drip pans must be cleaned periodically, and drip collected materials must be disposed of properly.

o Pave loading areas with concrete instead of asphalt.

o Avoid placing storm drains inlets in the area.

o Grade and/or berm the loading/unloading area with drainage to sump; regularly remove materials accumulated in sump.

Spill Response and Prevention Procedures

o Keep your spill prevention and control plan up-to-date or have an emergency spill cleanup plan readily available, as applicable.

o Contain leaks during transfer.

o Store and maintain appropriate spill cleanup materials in a location that is readily accessible and known to all employees.

o Ensure that employees are familiar with the site’s spill control plan and proper spill cleanup procedures.

o Use drip pans or comparable devices when transferring oils, solvents, and paints.

Material Handling and Waste Management

o Spot clean leaks and drips routinely to prevent runoff of spillage.

o Do not pour liquid wastes into floor drains, sinks, outdoor storm drain inlets, or other storm drains or sewer connections.

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o Do not put used or leftover cleaning solutions, solvents, and automotive fluids in the storm drain or sanitary sewer.

o Collect leaking or dripping fluids in drip pans or containers. Fluids are easier to recycle if kept separate.

o Promptly transfer used fluids to the proper waste or recycling drums. Do not leave drip pans or other open containers lying around.

o Minimize the possibility of stormwater pollution from outside waste receptacles by doing at least one of the following:

ü Use only watertight waste receptacle(s) and keep the lid(s) closed.

ü Grade and pave the waste receptacle area to prevent run-on of stormwater.

ü Install a roof over the waste receptacle area.

ü Install a low containment berm around the waste receptacle area.

ü Use and maintain drip pans under waste receptacles.

o Post “no littering” signs.

o Perform work area clean-up and dry sweep after daily operations.

Employee Training Program
o Train employees (e.g., fork lift operators) and contractors on proper spill containment and cleanup.

o Have employees trained in spill containment and cleanup present during loading/unloading.

o Train employees in proper handling techniques during liquid transfers to avoid spills.

o Make sure forklift operators are properly trained on loading and unloading procedures.

Quality Assurance and Record Keeping

o Keep accurate maintenance logs that document activities performed, quantities of materials removed, and improvement actions.

o Keep accurate logs of spill response actions that document what was spilled, how it was cleaned up, and how the waste was disposed.

o Establish procedures to complete logs and file them in the central office.

o Keep accurate logs of daily clean-up operations.

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o Space and time limitations may preclude all transfers from being performed indoors or under cover.

ü Designate specific areas for outdoor loading and unloading.

ü Require employees to understand and follow spill and leak prevention BMPs.

o It may not be possible to conduct transfers only during dry weather.

ü Limit materials and equipment rainfall exposure to all extents practicable.

ü Require employees to understand and follow spill and leak prevention BMPs.

Potential Capital Facility Costs and Operation & Maintenance Requirements
Facilities
Many facilities will already have indoor or covered areas where loading/unloading takes place and will require no additional capital expenditures.

If outdoor activities are required, construction of berms or other means to retain spills and leaks may require appropriate constructed systems for containment. These containment areas may require significant new capital investment.

Capital investments will likely be required at some sites if adequate cover and containment facilities do not exist and can vary significantly depending upon site conditions.

Maintenance
Most of the operations and maintenance activities associated with implementing this BMP are integrally linked to routine operations as previously described. Therefore additional O&M is not required.

o Conduct regular inspections and make repairs and improvements as necessary.

o Check loading and unloading equipment regularly for leaks.

o Conduct regular broom dry-sweeping of area. Do not wash with water.

Supplemental Information
Loading and Unloading of Liquids
o Loading or unloading of liquids should occur in the manufacturing building so that any spills that are not completely retained can be discharged to the sanitary sewer,

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treatment plant, or treated in a manner consistent with local sewer authorities and permit requirements.

o For loading and unloading tank trucks to above and below ground storage tanks, the following procedures should be used:

ü The area where the transfer takes place should be paved. If the liquid is reactive with the asphalt, Portland cement should be used to pave the area.

ü The transfer area should be designed to prevent run-on of stormwater from adjacent areas. Sloping the pad and using a curb, like a speed bump, around the uphill side of the transfer area should reduce run-on.

ü The transfer area should be designed to prevent runoff of spilled liquids from the area. Sloping the area to a drain should prevent runoff. The drain should be connected to a dead-end sump or to the sanitary sewer. A positive control valve should be installed on the drain.

o For transfer from rail cars to storage tanks that must occur outside, use the following procedures:

ü Drip pans should be placed at locations where spillage may occur, such as hose connections, hose reels, and filler nozzles. Use drip pans when making and breaking connections.

ü Drip pan systems should be installed between the rails to collect spillage from tank cars.

References and Resources
Minnesota Pollution Control Agency, Industrial Stormwater Best Management Practices Guidebook BMP 26 Fueling and Liquid Loading/Unloading Operations.

Available online at: http://www.pca.state.mn.us/index.php/view- document.html?gid=10557.

New Jersey Department of Environmental Protection, 2013. Basic Industrial Stormwater General Permit Guidance Document NJPDES General Permit No NJ0088315. Available online at:
http://www.nj.gov/dep/dwq/pdf/5G2_guidance_color.pdf .

Oregon Department of Environmental Quality, 2013. Industrial Stormwater Best Management Practices Manual- BMP 26 Fueling and Liquid Loading/Unloading Operations. Available online at:
http://www.deq.state.or.us/wq/wqpermit/docs/IndBMP021413.pdf .

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Sacramento Stormwater Management Program, Best Management Practices for Industrial Storm Water Pollution Control. Available online at:
http://www.msa.saccounty.net/sactostormwater/documents/guides/industrial-BMP- manual.pdf.

Sacramento County Environmental Management Stormwater Program: Best Management Practices. Available online at:
http://www.emd.saccounty.net/EnvHealth/Stormwater/Stormwater-BMPs.html .

Santa Clara Valley Urban Runoff Pollution Prevention Program. http://www.scvurppp- w2k.com/.

US EPA. National Pollutant Discharge Elimination System – Industrial Fact Sheet Series for Activities Covered by EPA’s Multi Sector General Permit. Available online at:
http://cfpub.epa.gov/npdes/stormwater/swsectors.cfm .

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Description
Outside process equipment operations and
maintenance can contaminate stormwater
runoff. Activities, such as grinding, painting,
coating, sanding, degreasing or parts cleaning,
landfills and waste piles, and solid waste
treatment and disposal are examples of
process operations that can lead to
contamination of stormwater runoff. The
targeted constituents will vary for each site
depending on the operation being performed.

Approach
Implement source control BMPs to limit
exposure of outdoor equipment to direct
precipitation and stormwater run-on. Refer to
SC-22 Vehicle and Equipment Repair for
additional information.

General Pollution Prevention Protocols

o Perform the activity during dry periods
whenever possible.

o Install secondary containment measures
where leaks and spills may occur.

o Use non-toxic chemicals for maintenance
and minimize or eliminate the use of
solvents.

o Connect process equipment area to public
sanitary sewer or facility wastewater
treatment system when possible. Some
jurisdictions require that secondary
containment areas be connected to the
sanitary sewer, prohibiting any hard
connections to the storm drain.

Good Housekeeping
o Manage materials and waste properly (see
Material Handling and Waste
Management) to reduce adverse impacts
on stormwater quality.

Objectives

n Cover
n Contain
n Educate
n Reduce/Minimize

Targeted Constituents

Sediment ü

Nutrients ü

Trash ü

Metals ü

Bacteria ü

Oil and Grease ü

Organics ü

Minimum BMPs Covered
Good Housekeeping
Preventative
Maintenance
Spill and Leak
Prevention and Response
Material Handling &
Waste Management
Erosion and Sediment
Controls
Employee Training
Program
Quality Assurance
Record Keeping
ü
ü

ü

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o Cover the work area with a permanent roof if possible.

o Use drop cloths for sanding and painting operations.

o Use a vacuum for fine particle clean-up in pavement cracks and crevices.

o Minimize contact of stormwater with outside process equipment operations through berming and drainage routing (run-on prevention).

o "Spot clean" leaks and drips routinely. Leaks are not cleaned up until the absorbent is picked up and disposed of properly.

o Paint signs on storm drain inlets to indicate that they are not to receive liquid or solid wastes.

o Use roll down or permanent walls when windy/breezy to prevent wind transport of particulates/pollutants.

Preventative Maintenance

o Design outdoor equipment areas to prevent stormwater runoff and spills. Use a perimeter drain or slope pavement inward with drainage to sump.

o Dry clean the work area regularly. Do not wash outdoor equipment with water if there is a direct connection to the storm drain.

o Pave area with concrete rather than asphalt.

o Inspect outdoor equipment regularly for leaks or spills. Also check for structural failure, spills and overfills due to operator error, and/or failure of piping system.

o Inspect and clean, if necessary, storm drain inlets and catch basins within the outdoor equipment area before October 1 each year.

Spill Response and Prevention Procedures

o Keep your Spill Prevention Control and Countermeasure (SPCC) Plan up-to-date.

o Have employees trained in emergency spill cleanup procedures present when dangerous waste, liquid chemicals, or other wastes are delivered.

o Place a stockpile of spill cleanup materials where it will be readily accessible.

o Prevent operator errors by using engineering safe guards and thus reducing accidental releases of pollutant.

Material Handling and Waste Management

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o Do not pour liquid wastes into floor drains, sinks, outdoor storm drain inlets, or other storm drain or sewer connections.

o Collect leaking or dripping fluids in drip pans or containers. Fluids are easier to recycle if kept separate.

o Promptly transfer used fluids to the proper waste or recycling drums. Do not leave drip pans or other open containers lying around.

o Minimize the possibility of stormwater pollution from outside waste receptacles by doing at least one of the following:

ü Use only watertight waste receptacle(s) and keep the lid(s) closed.

ü Grade and pave the waste receptacle area to prevent run-on of stormwater.

ü Install a roof over the waste receptacle area.

Employee Training Program

o Educate employees about pollution prevention measures and goals.

o Train employees on proper equipment operation and maintenance procedures.

o Train all employees upon hiring and annually thereafter on proper methods for handling and disposing of waste. Ensure that all employees understand stormwater discharge prohibitions, wastewater discharge requirements, and these best management practices.

o Use a training log or similar method to document training.

o Ensure that employees are familiar with the site’s spill control plan and/or proper spill cleanup procedures.

Quality Assurance and Record Keeping
o Keep accurate maintenance logs that document minimum BMP activities performed for outdoor equipment, types and quantities of materials removed and disposed of, and any improvement actions.

o Keep accurate logs of spill response actions that document what was spilled, how it was cleaned up, and how the waste was disposed.

o Establish procedures to complete logs and file them in the central office.

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o Providing cover over outdoor equipment may be impractical or cost-prohibitive.

ü Operate outdoor equipment only during periods of dry weather.

o Regular operations and time limitations may require outdoor activities during wet weather.

ü Designate specific areas for outdoor activities.

ü Allow time for work area clean-up after each shift.

ü Require employees to understand and follow preventive maintenance and spill and leak prevention BMPs.

ü Design and install secondary containment and good housekeeping BMPs for outdoor equipment area.

o Storage sheds often must meet building and fire code requirements.

Potential Capital Facility Costs and Operation & Maintenance Requirements
Facilities

o Many facilities will already have indoor covered areas where vehicle and equipment repairs take place and will require no additional capital expenditures.

o If outdoor activities are required, construction of berms or other means to retain spills and leaks may require appropriate constructed systems for containment. These containment areas may require significant new capital investment.

o Capital investments will likely be required at some sites if adequate cover and containment facilities do not exist and can vary significantly depending upon site conditions.

Maintenance

o Most of the operations and maintenance activities associated with implementing this BMP are integrally linked to routine operations as previously described. Therefore additional O&M is not required.

o For facilities responsible for pre-treating their wastewater prior to discharging, the proper functioning of structural treatment system is an important maintenance consideration.

o Routine cleanout of oil and grease is required for the devices to maintain their effectiveness, usually at least once a month. During periods of heavy rainfall, cleanout is required more often to ensure pollutants are not washed through the trap.

Sediment removal is also required on a regular basis to keep the device working efficiently.

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References and Resources
Minnesota Pollution Control Agency. Industrial Stormwater Best Management Practices Guidebook BMP 26 Fueling and Liquid Loading/Unloading Operations.

Available online at: http://www.pca.state.mn.us/index.php/view- document.html?gid=10557.

Oregon Department of Environmental Quality, Industrial Stormwater Best Management Practices Manual- BMP 26 Fueling and Liquid Loading/Unloading Operations, February 2013. Available online at:
http://www.deq.state.or.us/wq/wqpermit/docs/IndBMP021413.pdf .

Sacramento Stormwater Management Program. Best Management Practices for Industrial Storm Water Pollution Control. Available online at:
http://www.msa.saccounty.net/sactostormwater/documents/guides/industrial-BMP- manual.pdf.

Sacramento County Environmental Management Stormwater Program: Best Management Practices. Available online at:
http://www.emd.saccounty.net/EnvHealth/Stormwater/Stormwater-BMPs.html .

Santa Clara Valley Urban Runoff Pollution Prevention Program. http://www.scvurppp- w2k.com/

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Description
Improper storage and handling of solid wastes
can allow toxic compounds, oils and greases,
heavy metals, nutrients, suspended solids, and
other pollutants to enter stormwater runoff.

The discharge of pollutants to stormwater from
waste handling and disposal can be prevented
and reduced by tracking waste generation,
storage, and disposal; reducing waste
generation and disposal through source
reduction, reuse, and recycling; and preventing
run-on and runoff.

General Pollution Prevention Protocols
o Accomplish reduction in the amount of
waste generated using the following source
controls:

ü Production planning and sequencing;

ü Process or equipment modification;

ü Raw material substitution or
elimination;

ü Loss prevention and housekeeping;

ü Waste segregation and separation; and

ü Close loop recycling.

o Establish a material tracking system to
increase awareness about material usage.

This may reduce spills and minimize
contamination, thus reducing the amount of
waste produced.

o Recycle materials whenever possible.

Objectives

n Cover
n Contain
n Educate
n Reduce/Minimize
n Product Substitution

Targeted Constituents

Sediment
Nutrients
Trash
Metals ü

Bacteria ü
Oil and Grease ü

Organics ü

Minimum BMPs Covered
Good Housekeeping ü
Preventative
Maintenance ü
Spill and Leak Prevention
and Response ü
Material Handling &
Waste Management ü
Erosion and Sediment
Controls
Employee Training
Program ü
Quality Assurance Record
Keeping ü

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o Use the entire product before disposing of the container.

o To the extent possible, store wastes under cover or indoors after ensuring all safety concerns such as fire hazard and ventilation are addressed.

o Provide containers for each waste stream at each work station. Allow time after shift to clean area.

Good Housekeeping
o Cover storage containers with leak proof lids or some other means. If waste is not in containers, cover all waste piles (plastic tarps are acceptable coverage) and prevent stormwater run-on and runoff with a berm. The waste containers or piles must be covered except when in use.

o Use drip pans or absorbent materials whenever grease containers are emptied by vacuum trucks or other means. Grease cannot be left on the ground. Collected grease must be properly disposed of as garbage.

o Dispose of rinse and wash water from cleaning waste containers into a sanitary sewer if allowed by the local sewer authority. Do not discharge wash water to the street or storm drain. Clean in a designated wash area that drains to a clarifier.

o Transfer waste from damaged containers into safe containers.

o Take special care when loading or unloading wastes to minimize losses. Loading systems can be used to minimize spills and fugitive emission losses such as dust or mist. Vacuum transfer systems can minimize waste loss.

o Keep the waste management area clean at all times by sweeping and cleaning up spills immediately.

o Use dry methods when possible (e.g., sweeping, use of absorbents) when cleaning around restaurant/food handling dumpster areas. If water must be used after sweeping/using absorbents, collect water and discharge through grease interceptor to the sewer.

o Stencil or demarcate storm drains on the facility’s property with prohibitive message regarding waste disposal.

o Cover waste piles with temporary covering material such as reinforced tarpaulin, polyethylene, polyurethane, polypropylene or hypalon.

o If possible, move the activity indoor after ensuring all safety concerns such as fire hazard and ventilation are addressed.

Preventative Maintenance
o Prevent stormwater run-on from entering the waste management area by enclosing the area or building a berm around the area.

o Prevent waste materials from directly contacting rain.

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o Cover waste piles with temporary covering material such as reinforced tarpaulin, polyethylene, polyurethane, polypropylene or hypalon.

o Cover the area with a permanent roof if feasible.

o Cover dumpsters to prevent rain from washing waste out of holes or cracks in the bottom of the dumpster.

o Check waste containers weekly for leaks and to ensure that lids are on tightly.

Replace any that are leaking, corroded, or otherwise deteriorating.

o Sweep and clean the waste management area regularly. Use dry methods when possible (e.g., sweeping, vacuuming, use of absorbents) when cleaning around restaurant/food handling dumpster areas. If water must be used after sweeping/using absorbents, collect water and discharge through grease interceptor to the sewer.

o Inspect and replace faulty pumps or hoses regularly to minimize the potential of releases and spills.

o Repair leaking equipment including valves, lines, seals, or pumps promptly.

Spill Response and Prevention Procedures
o Keep your spill prevention and plan up-to-date.

o Have an emergency plan, equipment and trained personnel ready at all times to deal immediately with major spills.

o Collect all spilled liquids and properly dispose of them.

o Store and maintain appropriate spill cleanup materials in a location known to all near the designated wash area.

o Ensure that vehicles transporting waste have spill prevention equipment that can prevent spills during transport. Spill prevention equipment includes:

ü Vehicles equipped with baffles for liquid waste; and

ü Trucks with sealed gates and spill guards for solid waste.

Material Handling and Waste Management
Litter Control
o Post “No Littering” signs and enforce anti-litter laws.

o Provide a sufficient number of litter receptacles for the facility.

o Clean out and cover litter receptacles frequently to prevent spillage.

Waste Collection
o Keep waste collection areas clean.

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o Inspect solid waste containers for structural damage regularly. Repair or replace damaged containers as necessary.

o Secure solid waste containers; containers must be closed tightly when not in use.

o Do not fill waste containers with washout water or any other liquid.

o Ensure that only appropriate solid wastes are added to the solid waste container.

Certain wastes such as hazardous wastes, appliances, fluorescent lamps, pesticides, etc., may not be disposed of in solid waste containers (see chemical/ hazardous waste collection section below).

o Do not mix wastes; this can cause chemical reactions, make recycling impossible, and complicate disposal. Affix labels to all waste containers.

Chemical/Hazardous Wastes
o Select designated hazardous waste collection areas on-site.

o Store hazardous materials and wastes in covered containers and protect them from vandalism.

o Place hazardous waste containers in secondary containment.

o Make sure that hazardous waste is collected, removed, and disposed of only at authorized disposal areas.

o Hazardous waste cannot be reused or recycled; it must be disposed of by a licensed hazardous waste hauler.

Employee Training Program
o Educate employees about pollution prevention measures and goals.

o Train employees how to properly handle and dispose of waste using the source control BMPs described above.

o Train employees and subcontractors in proper hazardous waste management.

o Use a training log or similar method to document training.

o Ensure that employees are familiar with the site’s spill control plan and/or proper spill cleanup procedures.

Quality Assurance and Record Keeping
o Keep accurate maintenance logs that document minimum BMP activities performed for waste handling and disposal, types and quantities of waste disposed of, and any improvement actions.

o Keep accurate logs of spill response actions that document what was spilled, how it was cleaned up, and how the waste was disposed.

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o Establish procedures to complete logs and file them in the central office.

Potential Capital Facility Costs and Operation & Maintenance Requirements
Facilities
o Capital costs will vary substantially depending on the size of the facility and the types of waste handled. Significant capital costs may be associated with reducing wastes by modifying processes or implementing closed-loop recycling.

o Many facilities will already have indoor covered areas where waste materials will be stored and will require no additional capital expenditures for providing cover.

o If outdoor storage of wastes is required, construction of berms or other means to prevent stormwater run-on and runoff may require appropriate constructed systems for containment.

o Capital investments will likely be required at some sites if adequate cover and containment facilities do not exist and can vary significantly depending upon site conditions.

Maintenance
o Check waste containers weekly for leaks and to ensure that lids are on tightly.

Replace any that are leaking, corroded, or otherwise deteriorating.

o Sweep and clean the waste management area regularly. Use dry methods when possible (e.g., sweeping, use of absorbents) when cleaning around restaurant/food handling dumpster areas. If water must be used after sweeping/using absorbents, collect water and discharge through grease interceptor to the sewer.

o Inspect and replace faulty pumps or hoses regularly to minimize the potential of releases and spills.

o Repair leaking equipment including valves, lines, seals, or pumps promptly.

References and Resources
Minnesota Pollution Control Agency, Industrial Stormwater Best Management Practices Guidebook. Available online at: http://www.pca.state.mn.us/index.php/view- document.html?gid=10557.

New Jersey Department of Environmental Protection, 2013. Basic Industrial Stormwater General Permit Guidance Document NJPDES General Permit No NJ0088315, Revised. Available online at:
http://www.nj.gov/dep/dwq/pdf/5G2_guidance_color.pdf .

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Sacramento County Environmental Management Stormwater Program: Best Management Practices. Available online at:
http://www.emd.saccounty.net/EnvHealth/Stormwater/Stormwater-BMPs.html .

Santa Clara Valley Urban Runoff Pollution Prevention Program. http://www.scvurppp- w2k.com/

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Description
Promote the use of less harmful products and
products that contain little or no TMDL and
303(d) list pollutants. Alternatives exist for
most product classes including chemical
fertilizers, pesticides, cleaning solutions,
janitorial chemicals, automotive and paint
products, and consumables (batteries,
fluorescent lamps).

Approach
Pattern a new program after the many
established programs around the state and
country. Integrate this best management
practice as much as possible with existing
programs at your facility.

Develop a comprehensive program based on:

o The “Precautionary Principle,” which is an
alternative to the "Risk Assessment" model
that says it's acceptable to use a potentially
harmful product until physical evidence of
its harmful effects are established and
deemed too costly from an environmental or
public health perspective. For instance, a
risk assessment approach might say it's
acceptable to use a pesticide until there is
direct proof of an environmental impact.

The Precautionary Principle approach is
used to evaluate whether a given product is
safe, whether it is really necessary, and
whether alternative products would perform
just as well.

o Environmentally Preferable Purchasing
Program to minimize the purchase of
products containing hazardous ingredients
used in the facility's custodial services, fleet
maintenance, and facility maintenance in
favor of using alternate products that pose
less risk to employees and to the
environment.

o Integrated Pest Management (IPM) or Less-
Toxic Pesticide Program, which uses a pest
management approach that minimizes the
use of toxic chemicals and gets rid of pests

Objectives

n Educate
n Reduce/Minimize
n Product Substitution

Targeted Constituents

Sediment

Nutrients ü

Trash

Metals ü
Bacteria

Oil and Grease ü

Organics ü
Minimum BMPs Covered
Good Housekeeping
Preventative Maintenance

Spill and Leak Prevention
and Response
Material Handling &
Waste Management
Erosion and Sediment
Controls
Employee Training
Program ü
Quality Assurance Record
Keeping

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by methods that pose a lower risk to employees, the public, and the environment.

o Energy Efficiency Program including no-cost and low-cost energy conservation and efficiency actions that can reduce both energy consumption and electricity bills, along with long-term energy efficiency investments.

Consider the following mechanisms for developing and implementing a comprehensive program:

o Policies

o Procedures

ü Standard operating procedures (SOPs);

ü Purchasing guidelines and procedures; and

ü Bid packages (services and supplies).

o Materials

ü Preferred or approved product and supplier lists;

ü Product and supplier evaluation criteria;

ü Training sessions and manuals; and

ü Fact sheets for employees.

Implement this BMP in conjunction with the Vehicle and Equipment Management fact sheets (SC-20 – SC-22) and SC-41 Building and Grounds Maintenance.

Employee Training Program

o Employees who handle potentially harmful materials should be trained in the use of safer alternatives.

o Purchasing departments should be trained on safer alternative products and encouraged to procure less hazardous materials and products that contain little or no harmful substances or TMDL pollutants.

o Employees and contractors / service providers can both be educated about safer alternatives by using information developed by a number of organizations including the references and resources provided in this fact sheet.

o Alternative products may not be available, suitable, or effective in every case.

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ü Minimize use of hazardous/harmful products if no alternative product is available.

Regulatory Considerations
This BMP has no regulatory requirements unless local/municipal ordinance applies.

Existing regulations already encourage facilities to reduce the use of hazardous materials through incentives such as reduced:

o Specialized equipment storage and handling requirements;

o Storm water runoff sampling requirements;

o Training and licensing requirements; and

o Record keeping and reporting requirements.

Cost Considerations
o The primary cost is for staff time to: 1) develop new policies and procedures and 2) educate purchasing departments and employees who handle potentially harmful materials about the availability, procurement, and use of safer alternatives.

o Some alternative products may be slightly more expensive than conventional products.

Supplemental Information
The following discussion provides some general information on safer alternatives. More specific information on particular hazardous materials and the available alternatives may be found in the references and resources listed below.

o Automotive products – Less toxic alternatives are not available for many automotive products, especially engine fluids. But there are alternatives to grease lubricants, car polishes, degreasers, and windshield washer solution. Refined motor oil is also available.

o Vehicle/Trailer lubrication – Fifth wheel bearings on trucks require routine lubrication. Adhesive lubricants are available to replace typical chassis grease.

o Cleaners – Vegetables-based or citrus-based soaps are available to replace petroleum-based soaps/detergents.

o Paint products – Water-based paints, wood preservatives, stains, and finishes with low VOC content are available.

o Pesticides – Specific alternative products or methods exist to control most insects, fungi, and weeds.

o Chemical Fertilizers – Compost and soil amendments are natural alternatives.

o Consumables – Manufacturers have either reduced or are in the process of reducing the amount of heavy metals in consumables such as batteries and fluorescent lamps.

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All fluorescent lamps contain mercury, however low-mercury containing lamps are now available from most hardware and lighting stores. Fluorescent lamps are also more energy efficient than the average incandescent lamp.

o Janitorial chemicals – Even biodegradable soap can harm fish and wildlife before it biodegrades. Biodegradable does not mean non-toxic. Safer products and procedures are available for floor stripping and cleaning, as well as carpet, glass, metal, and restroom cleaning and disinfecting. Use paper products with post- consumer recycled content and implement electric had dryers.

Examples
There are a number of business and trade associations, and communities with effective programs. Some of the more prominent are listed below in the references and resources section.

References and Resources
Note: Many of these references provide alternative products for materials that typically are used inside and disposed to the sanitary sewer as well as alternatives to products that usually end up in the storm drain.

General Sustainable Practices and Pollution Prevention Including Pollutant-Specific Information
California Department of Toxic Substances Control,
http://www.dtsc.ca.gov/PollutionPrevention/GreenTechnology/Index.cfm .

CalRecycle, http://www.calrecycle.ca.gov/Business/Regulated.htm .

City of Santa Monica Office of Sustainability and Environment, http://www.smgov.net/departments/ose/ .

City of Palo Alto, http:// www.city.palo-alto.ca.us/cleanbay .

City and County of San Francisco, Department of the Environment, http://www.sfenvironment.org/toxics-health/greener-business-practices .

Green Business Program, http://www.greenbiz.ca.gov/GRlocal.html .

Product Stewardship Institute, http://www.productstewardship.us/index.cfm .

Sacramento Clean Water Business Partners.
http://www.sacstormwater.org/CleanWaterBusinessPartners/CleanWaterBusinessPartn ers.html.

USEPA. National Pollutant Discharge Elimination System (NPDES) Stormwater Discharges From Industrial Facilities,
http://cfpub.epa.gov/npdes/stormwater/indust.cfm .

USEPA Region IX Pollution Prevention Program,
http://www.epa.gov/region9/waste/p2/business.html .

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Western Sustainability and Pollution Prevention Network, http://wsppn.org/ .

Metals (mercury, copper)
National Electrical Manufacturers Association – Environmental Stewardship, http://www.nema.org/Policy/Environmental-Stewardship/pages/default.aspx .

Sustainable Conservation, http://www.suscon.org .

Auto Recycling Project
Brake Pad Partnership
Pesticides and Chemical Fertilizers
Bio-Integral Resource Center, http://www.birc.org .

California Department of Pesticide Regulation,
http://www.cdpr.ca.gov/dprprograms.htm .

University of California Statewide IPM Program,
http://www.ipm.ucdavis.edu/default.html .

Dioxins
Bay Area Dioxins Project,
http://www.abag.ca.gov/bayarea/dioxin/project_materials.htm .

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Description
Stormwater runoff from building and grounds
maintenance activities can be contaminated
with toxic hydrocarbons in solvents, fertilizers
and pesticides, suspended solids, heavy metals,
abnormal pH, and oils and greases. Utilizing
the protocols in this fact sheet will prevent or
reduce the discharge of pollutants to
stormwater from building and grounds
maintenance activities by washing and cleaning
up with as little water as possible, following
good landscape management practices,
preventing and cleaning up spills immediately,
keeping debris from entering the storm drains,
and maintaining the stormwater collection
system.

Approach
Reduce potential for pollutant discharge

Objectives

n Cover
n Contain
n Educate
n Reduce/Minimize
n Product Substitution

Targeted Constituents
Sediment ü

Nutrients ü

Trash

Metals ü

Bacteria ü

Oil and Grease

Organics through source control pollution prevention
and BMP implementation. Successful
implementation depends on effective training
of employees on applicable BMPs and general
pollution prevention strategies and objectives.

General Pollution Prevention Protocols
Minimum BMPs Covered
Good Housekeeping ü
Preventative
Maintenance
Spill and Leak
o Switch to non-toxic chemicals for
maintenance to the maximum extent
possible.

Prevention and ü
Response
Material Handling &

o Choose cleaning agents that can be
recycled.

o Encourage proper lawn management and
landscaping, including use of native
vegetation.

o Encourage use of Integrated Pest
Management techniques for pest control.

o Encourage proper onsite recycling of yard
trimmings.

o Recycle residual paints, solvents, lumber,
and other material as much as possible.

Waste Management ü
Erosion and Sediment
Controls Employee Training
Program ü
Quality Assurance
Record Keeping ü

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o Clean work areas at the end of each work shift using dry cleaning methods such as sweeping and vacuuming.

Good Housekeeping
Pressure Washing of Buildings, Rooftops, and Other Large Objects o In situations where soaps or detergents are used and the surrounding area is paved, pressure washers must use a water collection device that enables collection of wash water and associated solids. A sump pump, wet vacuum or similarly effective device must be used to collect the runoff and loose materials. The collected runoff and solids must be disposed of properly.

o If soaps or detergents are not used, and the surrounding area is paved, wash runoff does not have to be collected but must be screened. Pressure washers must use filter fabric or some other type of screen on the ground and/or in the catch basin to trap the particles in wash water runoff.

o If you are pressure washing on a grassed area (with or without soap), runoff must be dispersed as sheet flow as much as possible, rather than as a concentrated stream.

The wash runoff must remain on the grass and not drain to pavement.

Landscaping Activities
o Dispose of grass clippings, leaves, sticks, or other collected vegetation as garbage, or by composting. Do not dispose of collected vegetation into waterways or storm drainage systems.

o Use mulch or other erosion control measures on exposed soils. See also SC-40, Contaminated and Erodible Areas, for more information.

Building Repair, Remodeling, and Construction
o Do not dump any toxic substance or liquid waste on the pavement, the ground, or toward a storm drain.

o Use ground or drop cloths underneath outdoor painting, scraping, and sandblasting work, and properly dispose of collected material daily.

o Use a ground cloth or oversized tub for activities such as paint mixing and tool cleaning.

o Clean paintbrushes and tools covered with water-based paints in sinks connected to sanitary sewers or in portable containers that can be dumped into a sanitary sewer drain. Brushes and tools covered with non-water-based paints, finishes, or other materials must be cleaned in a manner that enables collection of used solvents (e.g., paint thinner, turpentine, etc.) for recycling or proper disposal.

o Use a storm drain cover, filter fabric, or similarly effective runoff control mechanism if dust, grit, wash water, or other pollutants may escape the work area and enter a catch basin. This is particularly necessary on rainy days. The containment device(s) must be in place at the beginning of the work day, and accumulated dirty runoff and

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solids must be collected and disposed of before removing the containment device(s) at the end of the work day.

o If you need to de-water an excavation site, you may need to filter the water before discharging to a catch basin or off-site. If directed off-site, you should direct the water through hay bales and filter fabric or use other sediment filters or traps.

o Store toxic material under cover during precipitation events and when not in use. A cover would include tarps or other temporary cover material.

Mowing, Trimming, and Planting
o Dispose of leaves, sticks, or other collected vegetation as garbage, by composting or at a permitted landfill. Do not dispose of collected vegetation into waterways or storm drainage systems.

o Use mulch or other erosion control measures when soils are exposed.

o Place temporarily stockpiled material away from watercourses and drain inlets, and berm or cover stockpiles to prevent material releases to the storm drain system.

o Consider an alternative approach when bailing out muddy water: do not put it in the storm drain; pour over landscaped areas.

o Use hand weeding where practical.

Fertilizer and Pesticide Management
o Do not use pesticides if rain is expected.

o Do not mix or prepare pesticides for application near storm drains.

o Use the minimum amount needed for the job.

o Calibrate fertilizer distributors to avoid excessive application.

o Employ techniques to minimize off-target application (e.g., spray drift) of pesticides, including consideration of alternative application techniques.

o Apply pesticides only when wind speeds are low.

o Fertilizers should be worked into the soil rather than dumped or broadcast onto the surface.

o Irrigate slowly to prevent runoff and then only as much as is needed.

o Clean pavement and sidewalk if fertilizer is spilled on these surfaces before applying irrigation water.

Inspection
o Inspect irrigation system periodically to ensure that the right amount of water is being applied and that excessive runoff is not occurring. Minimize excess watering and repair leaks in the irrigation system as soon as they are observed.

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Spill Response and Prevention Procedures
o Keep your Spill Prevention Control and Countermeasure (SPCC) Plan up-to-date.

o Place a stockpile of spill cleanup materials, such as brooms, dustpans, and vacuum sweepers (if desired) near the storage area where it will be readily accessible.

o Have employees trained in spill containment and cleanup present during the loading/unloading of dangerous wastes, liquid chemicals, or other materials.

o Familiarize employees with the Spill Prevention Control and Countermeasure Plan.

o Clean up spills immediately.

Material Handling and Waste Management
o Follow all federal, state, and local laws and regulations governing the use, storage, and disposal of fertilizers and pesticides and training of applicators and pest control advisors.

o Use less toxic pesticides that will do the job when applicable. Avoid use of copper- based pesticides if possible.

o Dispose of empty pesticide containers according to the instructions on the container label.

o Use up the pesticides. Rinse containers, and use rinse water as product. Dispose of unused pesticide as hazardous waste.

o Implement storage requirements for pesticide products with guidance from the local fire department and County Agricultural Commissioner. Provide secondary containment for pesticides.

Employee Training Program
o Educate and train employees on pesticide use and in pesticide application techniques to prevent pollution.

o Train employees and contractors in proper techniques for spill containment and cleanup.

o Be sure the frequency of training takes into account the complexity of the operations and the needs of individual staff.

Quality Assurance and Record Keeping
o Keep accurate logs that document maintenance activities performed and minimum BMP measures implemented.

o Keep accurate logs of spill response actions that document what was spilled, how it was cleaned up, and how the waste was disposed.

o Establish procedures to complete logs and file them in the central office.

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Potential Capital Facility Costs and Operation & Maintenance Requirements
Facilities
o Additional capital costs are not anticipated for building and grounds maintenance.

Implementation of the minimum BMPs described above should be conducted as part of regular site operations.

Maintenance
o Maintenance activities for the BMPs described above will be minimal, and no additional cost is anticipated.

Supplemental Information
Fire Sprinkler Line Flushing
Site fire sprinkler line flushing may be a source of non-stormwater runoff pollution. The water entering the system is usually potable water, though in some areas it may be non- potable reclaimed wastewater. There are subsequent factors that may drastically reduce the quality of the water in such systems. Black iron pipe is usually used since it is cheaper than potable piping, but it is subject to rusting and results in lower quality water. Initially, the black iron pipe has an oil coating to protect it from rusting between manufacture and installation; this will contaminate the water from the first flush but not from subsequent flushes. Nitrates, poly-phosphates and other corrosion inhibitors, as well as fire suppressants and antifreeze may be added to the sprinkler water system.

Water generally remains in the sprinkler system a long time (typically a year) and between flushes may accumulate iron, manganese, lead, copper, nickel, and zinc. The water generally becomes anoxic and contains living and dead bacteria and breakdown products from chlorination. This may result in a significant BOD problem and the water often smells. Consequently dispose fire sprinkler line flush water into the sanitary sewer.

Do not allow discharge to storm drain or infiltration due to potential high levels of pollutants in fire sprinkler line water.

References and Resources
City of Seattle, Seattle Public Utilities Department of Planning and Development, 2009.

Stormwater Manual Vol. 1 Source Control Technical Requirements Manual.

Kennedy/Jenks Consultants, 2007. The Truckee Meadows Industrial and Commercial Storm Water Best Management Practices Handbook. Available online at:
http://www.cityofsparks.us/sites/default/files/assets/documents/env- control/construction/TM-I-C_BMP_Handbook_2-07-final.pdf.

Sacramento Stormwater Management Program. Best Management Practices for Industrial Storm Water Pollution Control. Available online at:

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http://www.msa.saccounty.net/sactostormwater/documents/guides/industrial-BMP- manual.pdf.

US EPA, 1997. Best Management Practices Handbook for Hazardous Waste Containers. Available online at: http://www.epa.gov/region6/6en/h/handbk4.pdf .

Ventura Countywide Stormwater Management Program Clean Business Fact Sheets.

Available online at:
http://www.vcstormwater.org/documents/programs_business/building.pdf .

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Description
Site modifications are common, particularly at
large industrial sites. The activity may vary
from minor and normal building repair to
major remodeling, or the construction of new
facilities. These activities can generate
pollutants including solvents, paints, paint and
varnish removers, finishing residues, spent

Objectives
n Cover
n Contain
n Educate
n Reduce/Minimize
n Product Substitution
thinners, soap cleaners, kerosene, asphalt and
concrete materials, adhesive residues, and old
asbestos installation. Protocols in this fact
sheet are intended to prevent or reduce the
discharge of pollutants to stormwater from
building repair, remodeling, and minor
construction by using soil erosion controls,
enclosing or covering building material storage
areas, using good housekeeping practices, using
safer alternative products, and training
employees.

This fact sheet is intended to be used for minor
repairs and construction. If major construction
is required, the guidelines in the Construction
BMP Handbook should be followed.

Approach
Targeted Constituents

Sediment ü

Nutrients

Trash ü

Metals ü
Bacteria

Oil and Grease ü

Organics ü

Minimum BMPs Covered

Good Housekeeping ü
Preventative
Maintenance
Spill and Leak
The BMP approach is to reduce potential for
pollutant discharges through source control
pollution prevention and BMP implementation.

Successful implementation depends on
effective training of employees on applicable
BMPs and general pollution prevention
strategies and objectives.

General Pollution Prevention Protocols
o Recycle residual paints, solvents, lumber,
and other materials to the maximum extent
practicable.

o Avoid outdoor repairs and construction
during periods of wet weather.

o Use safer alternative products to the
maximum extent practicable. See also SC-
35 Safer Alternative Products for more
information.

Prevention and ü
Response
Material Handling &
Waste Management
Erosion and Sediment
Controls
Employee Training
Program
Quality Assurance
Record Keeping
ü
ü

ü

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o Buy recycled products to the maximum extent practicable.

o Inform on-site contractors of company policy on these matters and include appropriate provisions in their contract to ensure certain proper housekeeping and disposal practices are implemented.

o Make sure that nearby storm drains are well marked to minimize the chance of inadvertent disposal of residual paints and other liquids.

Good Housekeeping
Repair & Remodeling
o Keep the work site clean and orderly. Remove debris in a timely fashion. Sweep and vacuum the area regularly to remove sediments and small debris.

o Cover raw materials of particular concern that must be left outside, particularly during the rainy season. See also SC-33 Outdoor Storage of Raw Materials for more information.

o Use equipment and tools such as bag sanders to reduce accumulation of debris.

o Limit/prohibit work on windy days; implement roll-down walls or other measures to reduce wind transport of pollutants.

o Do not dump waste liquids down the storm drain.

o Dispose of wash water, sweepings, and sediments properly.

o Store liquid materials properly that are normally used in repair and remodeling such as paints and solvents. See also SC-31 Outdoor Liquid Container Storage for more information.

o Sweep out rain gutters or wash the gutter and trap the particles at the outlet of the downspout. A sock or geofabric placed over the outlet may effectively trap the materials. If the downspout is tight lined, place a temporary plug at the first convenient point in the storm drain and pump out the water with a vactor truck, and clean the catch basin sump where you placed the plug.

o Clean the storm drain system in the immediate vicinity of the construction activity after it is completed. See also SC-44 Drainage System Maintenance for more information.

Painting
o Enclose painting operations consistent with local air quality regulations and OSHA.

o Local air pollution regulations may, in many areas of the state, specify painting procedures which if properly carried out are usually sufficient to protect water quality.

o Develop paint handling procedures for proper use, storage, and disposal of paints.

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o Transport paint and materials to and from job sites in containers with secure lids and tied down to the transport vehicle.

o Test and inspect spray equipment prior to starting to paint. Tighten all hoses and connections and do not overfill paint containers.

o Mix paint indoors before using so that any spill will not be exposed to rain. Do so even during dry weather because cleanup of a spill will never be 100 percent effective.

o Transfer and load paint and hot thermoplastic away from storm drain inlets.

o Do not transfer or load paint near storm drain inlets.

o Plug nearby storm drain inlets prior to starting painting and remove plugs when job is complete when there is risk of a spill reaching storm drains.

o Cover nearby storm drain inlets prior to starting work if sand blasting is used to remove paint.

o Use a ground cloth to collect the chips if painting requires scraping or sand blasting of the existing surface. Dispose of the residue properly.

o Cover or enclose painting operations properly to avoid drift.

o Clean the application equipment in a sink that is connected to the sanitary sewer if using water based paints.

o Capture all cleanup-water and dispose of properly.

o Dispose of paints containing lead or tributyl tin and considered a hazardous waste properly.

o Store leftover paints if they are to be kept for the next job properly, or dispose properly.

o Recycle paint when possible. Dispose of paint at an appropriate household hazardous waste facility.

Spill Response and Prevention Procedures
o Keep your spill prevention and control plan up-to-date.

o Place a stockpile of spill cleanup materials where it will be readily accessible.

o Clean up spills immediately.

o Excavate and remove the contaminated (stained) soil if a spill occurs on dirt.

Material Handling and Waste Management
o Post “No Littering” signs and enforce anti-litter laws.

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o Provide a sufficient number of litter receptacles for the facility.

o Clean out and cover litter receptacles frequently to prevent spillage.

o Keep waste collection areas clean.

o Inspect solid waste containers for structural damage regularly. Repair or replace damaged containers as necessary.

o Secure solid waste containers; containers must be closed tightly when not in use.

o Do not fill waste containers with washout water or any other liquid.

o Ensure that only appropriate solid wastes are added to the solid waste container.

Certain wastes such as hazardous wastes, appliances, fluorescent lamps, pesticides, etc., may not be disposed of in solid waste containers (see chemical/ hazardous waste collection section below).

o Do not mix wastes; this can cause chemical reactions, make recycling impossible, and complicate disposal. Affix labels to all waste containers.

o Make sure that hazardous waste is collected, removed, and disposed of properly. See also SC-34, Waste Handling and Disposal for more information.

Sediment and Erosion Controls
o Limit disturbance to bare soils and preserve natural vegetation whenever possible.

See also EC-2, Preservation of Existing Vegetation, in the Construction BMP Handbook.

o Stabilize loose soils by re-vegetating whenever possible. See also EC-4 Hydroseeding, in the Construction BMP Handbook.

o Utilize non-vegetative stabilization methods for areas prone to erosion where vegetative options are not feasible. Examples include:

ü Areas of vehicular or pedestrian traffic such as roads or paths;

ü Arid environments where vegetation would not provide timely ground coverage, or would require excessive irrigation;

ü Rocky substrate, infertile or droughty soils where vegetation would be difficult to establish; and

ü Areas where vegetation will not grow adequately within the construction time frame.

There are several non-vegetative stabilization methods and selection should be based on site-specific conditions. See also EC-16 Non-Vegetative Stabilization, in the Construction BMP Handbook.

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o Utilize chemical stabilization when needed. See also EC-5 Soil Binders, in the Construction BMP Handbook.

o Use geosynthetic membranes to control erosion if feasible. See also EC-7 Geotextiles and Mats, in the Construction BMP Handbook.

o Stabilize all roadways, entrances, and exits to sufficiently control discharges of erodible materials from discharging or being tracked off the site. See also TC 1-3 Tracking Control, in the Construction BMP Handbook.

o Refer to the supplemental information provided below for projects that involve more extensive soil disturbance activities.

Employee Training Program
o Educate employees about pollution prevention measures and goals.

o Train employees how to properly implement the source control BMPs described above. Detailed information for Sediment and Erosion Control BMPs is provided in the Construction BMP Handbook.

o Proper education of off-site contractors is often overlooked. The conscientious efforts of well trained employees can be lost by unknowing off-site contractors, so make sure they are well informed about pollutant source control responsibilities.

o Use a training log or similar method to document training.

Quality Assurance and Record Keeping
o Keep accurate maintenance logs that document minimum BMP activities performed for building repair and construction, types and quantities of waste disposed of, and any improvement actions.

o Keep accurate logs of spill response actions that document what was spilled, how it was cleaned up, and how the waste was disposed.

o Establish procedures to complete logs and file them in the central office.

o This BMP is for minor construction only. The State’s General Construction Activity Stormwater Permit has more extensive requirements for larger projects that would disturb one or more acres of surface.

ü Refer to the companion “Construction Best Management Practice Handbook” which contains specific guidance and best management practices for larger-scale projects.

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o Time constraints may require some outdoor repairs and construction during wet weather.

ü Require employees to understand and follow good housekeeping and spill and leak prevention BMPs.

ü Inspect sediment and erosion control BMPs daily during periods of wet weather and repair or improve BMP implementation as necessary.

o Hazardous waste that cannot be reused or recycled must be disposed of by a licensed hazardous waste hauler.

ü Minimize use of hazardous materials to the maximum extent practicable.

o Be certain that actions to help stormwater quality are consistent with Cal- and Fed- OSHA and air quality regulations.

o Prices for recycled/safer alternative materials and fluids may be higher than those of conventional materials.

Potential Capital Facility Costs and Operation & Maintenance Requirements
Facilities
o Limited capital investments may be required at some sites if adequate cover and containment facilities do not exist for construction materials and wastes.

o Purchase and installation of erosion and sediment controls, if needed will require additional capital investments, and this amount will vary depending on site characteristics and the types of BMPs being implemented.

o Minimize costs by maintaining existing vegetation and limiting construction operations on bare soils.

Maintenance
o The erosion and sediment control BMPs described above require periodic inspection and maintenance to remain effective. The cost of these actions will vary depending on site characteristics and the types of BMPs being implemented.

o Irrigation costs may be required to establish and maintain vegetation.

Supplemental Information
Soil/Erosion Control
If the work involves exposing large areas of soil, employ the appropriate soil erosion and control techniques. See the Construction Best Management Practice Handbook. If old buildings are being torn down and not replaced in the near future, stabilize the site using measures described in SC-40 Contaminated or Erodible Areas.

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Building Repair and Construction SC-42
September 2014 California Stormwater BMP Handbook
Industrial and Commercial
www.casqa.org
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If a building is to be placed over an open area with a storm drainage system, make sure the storm inlets within the building are covered or removed, or the storm line is connected to the sanitary sewer. If because of the remodeling a new drainage system is to be installed or the existing system is to be modified, consider installing catch basins as they serve as effective “in-line” treatment devices. Include in the catch basin a “turn- down” elbow or similar device to trap floatables.

References and Resources
City of Seattle, Seattle Public Utilities Department of Planning and Development, 2009.

Stormwater Manual Vol. 1 Source Control Technical Requirements Manual.

California Stormwater Quality Association, 2012. Construction Stormwater Best Management Practice Handbook. Available at http://www.casqa.org .

US EPA. Construction Site Stormwater Runoff Control. Available online at:
http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm?action=min_measure &min_measure_id=4.

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Parking Area Maintenance SC-43
September 2014 California Stormwater BMP Handbook
Industrial and Commercial
www.casqa.org
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Description
Parking lots can contribute a number of
substances, such as trash, suspended solids,
hydrocarbons, oil and grease, and heavy metals
that can enter receiving waters through
stormwater runoff or non-stormwater
discharges. The protocols in this fact sheet are
intended to prevent or reduce the discharge of

Objectives

n Cover
n Contain
n Educate
n Reduce/Minimize
n Product Substitution
pollutants from parking areas and include
using good housekeeping practices, following
appropriate cleaning BMPs, and training
employees.

BMPs for other outdoor areas on site
(loading/unloading, material storage, and
equipment operations) are described in SC-30
through SC-33.

Approach
The goal of this program is to ensure
stormwater pollution prevention practices are
considered when conducting activities on or
around parking areas to reduce potential for
pollutant discharge to receiving waters.

Targeted Constituents

Sediment ü

Nutrients
Trash ü

Metals ü

Bacteria

Oil and Grease ü

Organics ü

Minimum BMPs Covered
Good Housekeeping ü
Preventative
Maintenance ü
Spill and Leak
Successful implementation depends on
effective training of employees on applicable
BMPs and general pollution prevention
strategies and objectives.

General Pollution Prevention Protocols
o Encourage advanced designs and
maintenance strategies for impervious
parking lots. Refer to the treatment control
BMP fact sheets in this manual for
additional information.

o Keep accurate maintenance logs to evaluate
BMP implementation.

Good Housekeeping
o Keep all parking areas clean and orderly.

Remove debris, litter, and sediments in a
timely fashion.

o Post “No Littering” signs and enforce anti-
litter laws.

Prevention and ü
Response
Material Handling &
Waste Management
Erosion and Sediment
Controls
Employee Training
Program ü
Quality Assurance
Record Keeping ü

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Parking Area Maintenance SC-43
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Industrial and Commercial
www.casqa.org
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o Provide an adequate number of litter receptacles.

o Clean out and cover litter receptacles frequently to prevent spillage.

Preventative Maintenance
Inspection
Have designated personnel conduct inspections of parking facilities and stormwater conveyance systems associated with parking facilities on a regular basis.

o Inspect cleaning equipment/sweepers for leaks on a regular basis.

Surface Cleaning
o Use dry cleaning methods (e.g., sweeping, vacuuming) to prevent the discharge of pollutants into the stormwater conveyance system if possible.

o Establish frequency of public parking lot sweeping based on usage and field observations of waste accumulation.

o Sweep all parking lots at least once before the onset of the wet season.

o Dispose of parking lot sweeping debris and dirt at a landfill.

o Follow the procedures below if water is used to clean surfaces:

ü Block the storm drain or contain runoff.

ü Collect and pump wash water to the sanitary sewer or discharge to a pervious surface. Do not allow wash water to enter storm drains.

o Follow the procedures below when cleaning heavy oily deposits:

ü Clean oily spots with absorbent materials.

ü Use a screen or filter fabric over inlet, then wash surfaces.

ü Do not allow discharges to the storm drain.

ü Vacuum/pump discharges to a tank or discharge to sanitary sewer.

ü Dispose of spilled materials and absorbents appropriately.

Surface Repair
o Check local ordinance for SUSMP/LID ordinance.

o Preheat, transfer or load hot bituminous material away from storm drain inlets.

o Apply concrete, asphalt, and seal coat during dry weather to prevent contamination from contacting stormwater runoff.

o Cover and seal nearby storm drain inlets where applicable (with waterproof material or mesh) and manholes before applying seal coat, slurry seal, etc. Leave covers in

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Parking Area Maintenance SC-43
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Industrial and Commercial
www.casqa.org
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place until job is complete and all water from emulsified oil sealants has drained or evaporated. Clean any debris from these covered manholes and drains for proper disposal.

o Use only as much water as necessary for dust control during sweeping to avoid runoff.

o Catch drips from paving equipment that is not in use with pans or absorbent material placed under the machines. Dispose of collected material and absorbents properly.

Spill Response and Prevention Procedures
o Keep your Spill Prevention Control and Countermeasure (SPCC) Plan up-to-date.

o Place a stockpile of spill cleanup materials where it will be readily accessible or at a central location.

o Clean up fluid spills immediately with absorbent rags or material.

o Dispose of spilled material and absorbents properly.

Employee Training Program
o Provide regular training to field employees and/or contractors regarding cleaning of paved areas and proper operation of equipment.

o Train employees and contractors in proper techniques for spill containment and cleanup.

o Use a training log or similar method to document training.

Quality Assurance and Record Keeping
o Keep accurate maintenance logs that document minimum BMP activities performed for parking area maintenance, types and quantities of waste disposed of, and any improvement actions.

o Keep accurate logs of spill response actions that document what was spilled, how it was cleaned up, and how the waste was disposed.

o Establish procedures to complete logs and file them in the central office.

Potential Capital Facility Costs and Operation & Maintenance Requirements
Facilities
o Capital investments may be required at some sites to purchase sweeping equipment, train sweeper operators, install oil/water/sand separators, or implement advanced BMPs. These costs can vary significantly depending upon site conditions and the amount of BMPs required.

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Parking Area Maintenance SC-43
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Industrial and Commercial
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Maintenance
o Sweep and clean parking lots regularly to minimize pollutant transport into storm drains from stormwater runoff.

o Clean out oil/water/sand separators regularly, especially after heavy storms.

o Maintain advanced BMPs such as vegetated swales, infiltration trenches, or detention basins as appropriate. Refer to the treatment control fact sheets for more information.

Supplemental Information
Advanced BMPs
Some parking areas may require advanced BMPs to further reduce pollutants in stormwater runoff, and a few examples are listed below. Refer to the Treatment Control Fact Sheets and the New Development and Redevelopment Manual for more information.

o When possible, direct sheet runoff to flow into biofilters (vegetated strip and swale) and/or infiltration devices.

o Utilize sand filters or oleophilic collectors for oily waste in low quantities.

o Arrange rooftop drains to prevent drainage directly onto paved surfaces.

o Design lot to include semi-permeable hardscape.

References and Resources
City of Seattle, Seattle Public Utilities Department of Planning and Development, 2009.

Stormwater Manual Vol. 1 Source Control Technical Requirements Manual.

California Stormwater Quality Association, 2003. New Development and Redevelopment Stormwater Best Management Practice Handbook. Available online at:
https://www.casqa.org/resources/bmp-handbooks/new-development-redevelopment- bmp-handbook.

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Beaumont City CouncilMarch 7, 2023

Beaumont City Council
March 7, 2023