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SIERRA LUMBER Ground Water Pump Test Calculations Assumptions • A constant ground water pumping rate of 13 GPM I • The effective porosity of soil at the site is 35% • The Jacobs Straight Line Method can be utilized to calculate transmissiv[ty (T) and storat[vity(S)utilizing draw-down versus time(minutes) on semi-loganthmic paper for each well location (Appendix J) Q = constant ground water pumping rate As = draw-down per 1-loganthmxc cycle to=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. IT =264Q—Os -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' days, so S = 0 3 (T)(to) —rz 4 0 3 (9,533 gpd/ft)(9 03 x 10' days) — (15)2 = 0.011 MW-2: Q = 13 GPM; As = 0.82 ft , to= 1.3 minutes; r = 10 ft. T = 264Q—As -t~ 264(13 GPM) — 0 82 ft=4,185 gpd/ft to= 1 3 minutes (1 hr/60mm)(1 day/24hr) = 9 03 x 10 4 days, so S = 0 3 (T)(to) —r2 -4 0 3 (5,720 gpd/ft)(9 03 x 104 days) — (10)2 = 0.011 MW-4a• Q = 13 GPM; As = 0.74 ft.; to= 1.3 minutes; r = 4 ft. T = 264Q—As -4 264(13 GPM) — 0 74 ft = 4,638 gpd/ft t4= 1 3 minutes (l hr/60mfn)(lday/24hr) = 9 03 x 10' days, so S = 0 3 (T)(to) — r2 -4 0 3 (4,638 gpd/ft)(9 03 x 104 days) — (4)2 = 0.079 EW-1: Q = 13 GPM; As = 9.6 ft.; to= 0.5 minutes; r= 0.5 ft. — — d ft T —264Q—Ds -� 264(13 GPM) 9 6 ft — 357.5 gp / ' to- 0 5 minutes (1 hr/60min)(1 day/24hr) = 3 47 x 104 days, so S = 0 3 (T)(to) —r2 -4 0 3 (357 5 gpd/ft)(3 47 x 10.4 days) — (0 5)2 = 0.15 1'0 Advanced GeoEn�ironmental,Inc