Drainage Report

Basin 5 w/ exfiltration Proposed basin 5 R5 infilt NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 3 Pond 24P: Infiltration basin 5 Hydrograph Inflow 4.83 cfs Outflow Inflow Area=2.275 ac Discarded Primary 5 Peak Elev=571.63' Storage=13,994 cf 4 Flow (cfs) 3 2 1 0.10 cfs 0.10 cfs 0.00 cfs 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 Time (hours)

Basin 5 w/ exfiltration Proposed basin 5 R5 infilt NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 4 Hydrograph for Pond 24P: Infiltration basin 5 Time Inflow Storage Elevation Outflow Discarded Primary (hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs) 0.00 0.00 0 570.50 0.00 0.00 0.00 1.50 0.01 4 570.50 0.00 0.00 0.00 3.00 0.03 77 570.51 0.02 0.02 0.00 4.50 0.05 171 570.51 0.04 0.04 0.00 6.00 0.07 255 570.52 0.05 0.05 0.00 7.50 0.10 361 570.53 0.08 0.08 0.00 9.00 0.14 530 570.54 0.09 0.09 0.00 10.50 0.25 1,055 570.59 0.09 0.09 0.00 12.00 2.12 3,968 570.82 0.09 0.09 0.00 13.50 0.45 11,803 571.45 0.09 0.09 0.00 15.00 0.23 12,993 571.55 0.10 0.10 0.00 16.50 0.17 13,531 571.59 0.10 0.10 0.00 18.00 0.13 13,822 571.61 0.10 0.10 0.00 19.50 0.11 13,937 571.62 0.10 0.10 0.00 21.00 0.10 13,990 571.63 0.10 0.10 0.00 22.50 0.09 13,982 571.63 0.10 0.10 0.00 24.00 0.08 13,913 571.62 0.10 0.10 0.00 25.50 0.00 13,446 571.58 0.10 0.10 0.00 27.00 0.00 12,932 571.54 0.10 0.10 0.00 28.50 0.00 12,419 571.50 0.10 0.10 0.00 30.00 0.00 11,906 571.46 0.09 0.09 0.00 31.50 0.00 11,394 571.42 0.09 0.09 0.00 33.00 0.00 10,883 571.38

0.00 11,906 571.46 0.09 0.09 0.00 31.50 0.00 11,394 571.42 0.09 0.09 0.00 33.00 0.00 10,883 571.38 0.09 0.09 0.00 34.50 0.00 10,372 571.34 0.09 0.09 0.00 36.00 0.00 9,862 571.29 0.09 0.09 0.00 37.50 0.00 9,353 571.25 0.09 0.09 0.00 39.00 0.00 8,844 571.21 0.09 0.09 0.00 40.50 0.00 8,336 571.17 0.09 0.09 0.00 42.00 0.00 7,829 571.13 0.09 0.09 0.00 43.50 0.00 7,322 571.09 0.09 0.09 0.00 45.00 0.00 6,816 571.05 0.09 0.09 0.00 46.50 0.00 6,311 571.01 0.09 0.09 0.00 48.00 0.00 5,807 570.97 0.09 0.09 0.00 49.50 0.00 5,303 570.93 0.09 0.09 0.00 51.00 0.00 4,800 570.89 0.09 0.09 0.00 52.50 0.00 4,297 570.85 0.09 0.09 0.00 54.00 0.00 3,795 570.81 0.09 0.09 0.00 55.50 0.00 3,294 570.77 0.09 0.09 0.00 57.00 0.00 2,794 570.73 0.09 0.09 0.00 58.50 0.00 2,294 570.68 0.09 0.09 0.00 60.00 0.00 1,795 570.64 0.09 0.09 0.00 61.50 0.00 1,296 570.60 0.09 0.09 0.00 63.00 0.00 798 570.56 0.09 0.09 0.00 64.50 0.00 320 570.53 0.07 0.07 0.00 66.00 0.00 102 570.51 0.02 0.02 0.00 67.50 0.00 32 570.50 0.01 0.01 0.00 69.00 0.00 10 570.50 0.00 0.00 0.00 70.50 0.00 3 570.50 0.00 0.00 0.00 72.00 0.00 1 570.50 0.00 0.00 0.00

Basin 5 w/ exfiltration Proposed basin 5 R5 infilt NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 5 Stage-Discharge for Pond 24P: Infiltration basin 5 Elevation Discharge Discarded Primary Elevation Discharge Discarded Primary (feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs) 570.50 0.00 0.00 0.00 573.05 2.34 0.10 2.24 570.55 0.09 0.09 0.00 573.10 2.49 0.10 2.39 570.60 0.09 0.09 0.00 573.15 2.63 0.10 2.53 570.65 0.09 0.09 0.00 573.20 2.75 0.10 2.65 570.70 0.09 0.09 0.00 573.25 2.88 0.10 2.78 570.75 0.09 0.09 0.00 573.30 2.99 0.10 2.89 570.80 0.09 0.09 0.00 573.35 3.11 0.10 3.00 570.85 0.09 0.09 0.00 573.40 3.21 0.10 3.11 570.90 0.09 0.09 0.00 573.45 3.32 0.10 3.22 570.95 0.09 0.09 0.00 573.50 3.42 0.10 3.32 571.00 0.09 0.09 0.00 573.55 3.52 0.10 3.41 571.05 0.09 0.09 0.00 573.60 3.61 0.10 3.51 571.10 0.09 0.09 0.00 573.65 3.70 0.10 3.60 571.15 0.09 0.09 0.00 573.70 3.79 0.10 3.69 571.20 0.09 0.09 0.00 573.75 3.88 0.10 3.78 571.25 0.09 0.09 0.00 573.80 3.97 0.10 3.86 571.30 0.09 0.09 0.00 573.85 4.05 0.10 3.95 571.35 0.09 0.09 0.00 573.90 4.13 0.10

3.86 571.30 0.09 0.09 0.00 573.85 4.05 0.10 3.95 571.35 0.09 0.09 0.00 573.90 4.13 0.10 4.03 571.40 0.09 0.09 0.00 573.95 4.21 0.10 4.11 571.45 0.09 0.09 0.00 574.00 4.29 0.10 4.19 571.50 0.10 0.10 0.00 571.55 0.10 0.10 0.00 571.60 0.10 0.10 0.00 571.65 0.10 0.10 0.00 571.70 0.10 0.10 0.00 571.75 0.10 0.10 0.00 571.80 0.10 0.10 0.00 571.85 0.10 0.10 0.00 571.90 0.10 0.10 0.00 571.95 0.10 0.10 0.00 572.00 0.10 0.10 0.00 572.05 0.10 0.10 0.00 572.10 0.10 0.10 0.00 572.15 0.10 0.10 0.00 572.20 0.10 0.10 0.00 572.25 0.10 0.10 0.00 572.30 0.10 0.10 0.00 572.35 0.10 0.10 0.00 572.40 0.10 0.10 0.00 572.45 0.15 0.10 0.05 572.50 0.25 0.10 0.15 572.55 0.38 0.10 0.28 572.60 0.53 0.10 0.43 572.65 0.70 0.10 0.60 572.70 0.89 0.10 0.79 572.75 1.10 0.10 1.00 572.80 1.32 0.10 1.22 572.85 1.55 0.10 1.45 572.90 1.80 0.10 1.70 572.95 2.01 0.10 1.91 573.00 2.19 0.10 2.09

Basin 5 w/ exfiltration Proposed basin 5 R5 infilt NOAA 24-hr D 2-Year Rainfall=3.44" Prepared by Anderson Consulting Services Printed 10/29/2023 HydroCAD® 10.20-3f s/n 06666 © 2023 HydroCAD Software Solutions LLC Page 6 Stage-Area-Storage for Pond 24P: Infiltration basin 5 Elevation Surface Wetted Storage (feet) (sq-ft) (sq-ft) (cubic-feet) 570.50 12,410 12,410 0 570.60 12,410 12,449 1,241 570.70 12,410 12,489 2,482 570.80 12,410 12,528 3,723 570.90 12,410 12,568 4,964 571.00 12,410 12,607 6,205 571.10 12,410 12,647 7,446 571.20 12,410 12,686 8,687 571.30 12,410 12,726 9,928 571.40 12,410 12,765 11,169 571.50 12,410 12,805 12,410 571.60 12,410 12,844 13,651 571.70 12,410 12,884 14,892 571.80 12,410 12,923 16,133 571.90 12,410 12,963 17,374 572.00 12,410 13,002 18,615 572.10 12,410 13,042 19,856 572.20 12,410 13,081 21,097 572.30 12,410 13,121 22,338 572.40 12,410 13,160 23,579 572.50 12,410 13,200 24,820 572.60 12,410 13,239 26,061 572.70 12,410 13,279 27,302 572.80 12,410 13,318 28,543 572.90 12,410 13,358 29,784 573.00 12,410 13,397 31,025 573.10 12,410 13,437 32,266 573.20 12,410 13,476 33,507 573.30 12,410 13,516 34,748 573.40 12,410 13,555 35,989 573.50 12,410 13,595 37,230 573.60 12,410 13,634 38,471 573.70 12,410 13,674 39,712 573.80 12,410 13,713 40,953 573.90 12,410 13,753

12,410 13,634 38,471 573.70 12,410 13,674 39,712 573.80 12,410 13,713 40,953 573.90 12,410 13,753 42,194 574.00 12,410 13,792 43,435

Input Values Basin 1 0.32 R Recharge rate (permeability rate) (in/hr) Specific yield, Sy (dimensionless) R = 0.32 in/hr 0.150 Sy default value is 0.15; max value is 0.2 provided that a lab test data is submitted Horizontal hydraulic conductivity (in/hr) 0.32 Kh Kh = 5xRecharge Rate (R) in the coastal plain; Kh=R outside the coastal plain Kh = 0.32 in/hr 51.500 x 1/2 length of basin (x direction, in feet) 115.000 y 1/2 width of basin (y direction, in feet) t = 62.71 hrs. 62.71 t Duration of infiltration period (hours) 10.00 hi(0) Initial thickness of saturated zone (feet) 21.138 h(max) Maximum thickness of saturated zone (beneath center of basin at end of infiltration period) 11.138 Δh(max) Maximum groundwater mounding (beneath center of basin at end of infiltration period) Distance from Ground-water center of basin in x Mounding, in feet direction, in feet 11.138 0 11.116 10 Re-Calculate Now 10.996 20 10.570 30 Groundwater Mounding, in feet 9.350 40 12.000 6.312 50 2.167 60 10.000 0.507 70 0.089 80 8.000 0.014 90 6.000 4.000 2.000 0.000 0 10 20 30 40 50 60

2.000 0.000 0 10 20 30 40 50 60 70 80 90 100 Disclaimer This spreadsheet solving the Hantush (1967) equation for ground-water mounding beneath an infiltration basin is made available to the general public as a convenience for those wishing to replicate values documented in the USGS Scientific Investigations Report 2010-5102 "Groundwater mounding beneath hypothetical stormwater infiltration basins" or to calculate values based on user-specified site conditions. Any changes made to the spreadsheet (other than values identified as user-specified) after transmission from the USGS could have unintended, undesirable consequences. These consequences could include, but may not be limited to: erroneous output, numerical instabilities, and violations of underlying assumptions that are inherent in results presented in the accompanying USGS published report. The USGS assumes no responsibility for the consequences of any changes made to the spreadsheet. If changes are made to the spreadsheet, the user is responsible for documenting the changes and justifying the results and conclusions.

Input Values 0.45 R Recharge rate (permeability rate) (in/hr) Basin 2-1 Specific yield, Sy (dimensionless) 0.150 Sy default value is 0.15; max value is 0.2 provided that a lab test data is submitted Horizontal hydraulic conductivity (in/hr) R = 0.45 in/hr 0.45 Kh Kh = 5xRecharge Rate (R) in the coastal plain; Kh=R outside the coastal plain 7.000 x 1/2 length of basin (x direction, in feet) Kh = 0.45 in/hr 74.250 y 1/2 width of basin (y direction, in feet) 39.01 t Duration of infiltration period (hours) 10.00 hi(0) Initial thickness of saturated zone (feet) t = 39.01 hrs. 15.231 h(max) Maximum thickness of saturated zone (beneath center of basin at end of infiltration period) 5.231 Δh(max) Maximum groundwater mounding (beneath center of basin at end of infiltration period) Distance from Ground-water center of basin in x Mounding, in feet direction, in feet 5.231 0 2.965 10 Re-Calculate Now 0.816 20 0.150 30 Groundwater Mounding, in feet 0.021 40 6.000 0.005 50 0.003 60 5.000 0.003 70 0.003 80 4.000 0.003 90 3.000 2.000 1.000 0.000 0 10 20 30 40 50 60 70 80 90 100