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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 transmisslvlty (T) and storativity(S)utilizing draw-down versus time (minutes) on semi-loganthmlc paper for each well location (Appendix J) Q = constant ground water pumping rate As = draw-down per 1-logarithmic 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. T = 264Q-as -+ 264(13 GPM) - 0 36 ft = 9,533 gpd/ft to- 1 3 minutes (1 hr/60rnm)(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 104 days) - (15)2 = 0.011 • MW-2: Q = 13 GPM, As = 0.82 ft.; t4= 1.3 minutes; r= 10 ft. T = 264Q-As -4 264(13 GPM) --- 0 82 ft � 4,185 gpd/ft to= 1 3 minutes (1 hr/60mIn)(1 day/24hr) = 9 03 x 10"4 days, so S = 0 3 (T)(to) - r' -4 0 3 (5,720 gpd/ft)(9 03 x 10' days) - (10)2 = 0.011 MW-4a: Q = 13 GPM; As = 0.74 ft ; to= 1.3 minutes; r= 4 ft. T =264Q-Os -4 264(13 GPM) - 0 74 ft = 4,638 gpd/ft to= 1 3 minutes (1 W60rmn)(1 day/24hr) = 9 03 x 10-4 days, so S = 0 3 (T)(to) - r2-# 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--As -+ 264(13 GPM) - 9 6 ft = 357.5 gpd/ft to- 0 5 minutes (1 hr/60min)(1 day/24hr) = 3 47 x 10 4 days, so S = 0 3 (T)(to) - rz -4 0 3 (3 5 7 5 gpd/ft)(3 47 x 10.4 days) - (0 5)2 = 0.15 Advanced CeoEnvwonment4 Inc