Drainage Report

Input Values 0.37 R Recharge rate (permeability rate) (in/hr) Specific yield, Sy (dimensionless) Basin 3 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) 0.37 Kh Kh = 5xRecharge Rate (R) in the coastal plain; Kh=R outside the coastal plain R = 0.37 in/hr 17.500 x 1/2 length of basin (x direction, in feet) 63.500 y 1/2 width of basin (y direction, in feet) Kh = 0.37 in/hr 47.66 t Duration of infiltration period (hours) 10.00 hi(0) Initial thickness of saturated zone (feet) t = 47.66 hrs. 18.470 h(max) Maximum thickness of saturated zone (beneath center of basin at end of infiltration period) 8.470 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 8.470 0 7.432 10 Re-Calculate Now 3.733 20 0.977 30 Groundwater Mounding, in feet 0.176 40 9.000 0.024 50 8.000 0.005 60 0.003 70 7.000 0.003 80 6.000 0.003 90 5.000 4.000 3.000

6.000 0.003 90 5.000 4.000 3.000 2.000 1.000 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.