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act SIERRA LUMBER: Ground Water Pump Test Calculations Assumptions: A constant ground water pumping rate of 13.GPM • The effective porosity of soil at the site is 35% • The Jacobs Straight Line Method can:be utilized to calculate transmissivity (T) and storativity(S)utilizing draw-down versus time (minutes) on semi-logarithmic paper for each well location (Appendix J). Q = constant ground water pumping rate. As= draw-down per 1-logarithmic cycle. to W intercept of the straight line at the zero-time scale axis. r= radius from pumping well in feet. MW-1: Q = 13,GPM; As = 0.36 ft.; to= 1.3 minutes; r = 15 ft. T =264Q+As -4 264(13 GPM) -0.36 ft = 9,533 gpd/ft to, 1.3 minutes (1 hr/60min)(1 day/24hr) = 9.03 X:10-4 days, so -4 z_ S = 0.3 (T)(to) -r2 4 0.3 (9,533 d/ft)(9.03 x 10 days) -(15) - 0.011 ( )( o) gp MW-2: Q = 13 GPM; As = 0.82 ft.; to= 1.3 minutes; r= 10 ft. 4 T = 264Q-A s 264(13 GPM) -0.82 ft = 4,185 gpd/ft to= 1.3 minutes (l hr/60min)(l day/24hr) = 9.03 x 10-4 days, so S = 0.3 (T)(to) - r2 -+ 0.3 (5,720 gpd/ft)(9.03 x 10' days) (10)2 - 0.011 MW-4a: Q = 13 GPM; As = 0.74 ft.; t4= 1.3 minutes; r = 4 ft. T = 264Q-As 4 264(13 GPM) - 0.74 ft - 4,638 gpd/ft to- 1.3 minutes (1 hr/64min)(1 day/24hr) = 9.;03 x 10-4 days, so S - 0.3 (T)(to) - r24 0.3 (4,638 gpd/ft)(9.03 x 10'4 days) - (4)2- 0.079 EW-1: Q = 13 GPM; As = 9.6 ft.; to= 0.5 minutes; r= 0.5 ft. T = 264Q-0s -! 264(13 GPM) -9.6 ft = 357.5 gpd/ft to= 0.5 minutes (1 hr/64min)(1 day/24hr) = 3.47 x 10' days, so S = 0.3 (T)(to) - r2 -+ 0.3 (357.5 gpd/ft)(3.47 x 10-4 days) (0.5)2= 0.15 Advanced GeoEnviromnental.Inc-