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Ground Water Drawdown Test Calculations <br /> Mel Bokides Petroleum- Manteca Station <br /> ' 983 Moffat Boulevard, Manteca, California <br /> Assumptions: <br /> ' A constant ground water pumping rate of 5 gallons per minute test conducted on <br /> 13 May 2001. <br /> ' Wells are screened entirely through the upper water table. <br /> • Homogenous ground water aquifer characteristics at monitoring wells MW-1 through MW-6 <br /> and extraction well EW 1. <br /> • The Distance-Drawdown Method was appropriate to utilize to calculate transmissivity (T) <br /> and storativity(S) and hydraulic conductivity (K) utilizing draw-clown versus distance (feet) J <br /> ' on semi-logarithmic paper for each well location. <br /> ' Calculations: e <br /> T = 70Q/ds S = Tt/640 (r")2K= T/b <br /> ' T -transmissivity S - storativity K- hydraulic conductivity <br /> Y <br /> Where: <br /> Q - constant ground water pumping rate= 5 gallons per minute <br /> ' ds - draw-down per 1-logarithmic cycle = 0.5 feet <br /> ro=intercept of the straight line at the distance axis = 130 feet <br /> ' t - time or duration of measurements = 720 minutes <br /> lr—thickness of aquifer(semi penetrated or exposed) = 15 feet <br /> ' 23 May 2001 <br /> ' T = 70 (5 gpm) ­1 0.5 feet= 700 ft'/day or <br /> 700 ft' /day(1 gal day/ft/0.134 ft'/day) = 5,223 gal/day/ft <br /> ' S = 700 ft' /day(720 minutes) 640 (130)2 =0.047 <br />.,' K= 51,223 gal/day/ff._ 15 ft.= 348 ft/day ., <br /> 348 ft/day (1 cm/sec/2835 ft/day) = 0.123 cm/sec <br />