Laserfiche WebLink
Distance Drawdown Analysis Calculations <br /> Former HESS-DuBOIS CLEANERS <br /> 348 West Harding Way <br /> Stockton, California <br /> Assumptions: <br /> ' 0 A constant ground water pumping rate of 5 GPM for tests conducted on 30 August 2001. <br /> ' a Well EW-I is screened entirely through the upper water table, 25 to 50 feet bsg. <br /> • Homogenous ground water aquifer characteristics at observation wells MW-1 through MW-5 <br /> and MW-8 and MW-9 and ground water extraction well EW-1 (soil boring logs). <br /> • The Distance-Drawdown Method was used to calculate transmissivity(T) and storativity <br /> (S) and hydraulic conductivity (K) utilizing draw-down versus distance (feet) on semi- <br /> logarithmic paper for each well location. <br /> • Equations: <br /> T=70Q/ds S =Tt/640 ( ar )' K=T/b <br /> Where: <br /> K=hydraulic conductivity <br /> T=transmissivity <br /> S =storativity <br /> ' Q =constant ground water pumping rate = 5.0. GPM. <br /> As =draw-down per 1-logarithmic cycle (Appendix H) — 0.6 ft. <br /> t=time of pump test (Appendix G) =720 minutes <br /> ro = intercept of best fit line with the distance axis (Appendix H) = 60 feet <br /> b =aquifer thickness (semi penetrated or exposed screen length) <br /> 30 August 2001 <br /> T = 70(5 gpm)/0.6 ft= 583 feet' /day or <br /> 583 feet' /day(1 gal day/ft/0.134 feet' /day) =4,353 gal day/feet <br /> S = 583 feet '/day(720 minutes) /640 (60 feet)' =0.IS <br /> ' K=4,353 gal day/feet/25 feet= 174 feet/day <br /> K= 174 feet/day(lcm/sec/2835 feet/day) = 0.061 cm/sec <br /> I <br /> Advanced GeoEnviron[nental Inc. <br /> i <br />