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' FLAG CITY CHEVRON Assumptions Ground Water Pump Test Calculations ' ' • Pump Test No 1 extraction from EW-2 at constant ground water pumping rate of 4 0 GPM • Pump Test No 2 extraction from EW-2 at constant ground water pumping rate of 6 6 GPM ' • Pump Test No 3 extraction from EW-2 at constant ground water pumping rate of 10 0 GPM • Pump Test No 4 extraction from EW-3 at constant ground water pumping rate of 10 0 GPM I • The Jacobs Straight Line Method (Distance-Drawdown Method) can be utilized to calculate transmissivity(T) and specific yield utilizing draw-down versus distance on semi- ' logarithmic paper for each well location (Appendix F) T =transmissivity , S =specific yield ' Q =constant ground water pumping rate As =draw-down per 1-logarithmic cycle t =time of pump test ro =intercept of best fit line with the distance axis ie Pump Test No. 1: Q = 4.0 GPM; As = 2.7 ft.; t= 60 minute; ro = 17 ft. lT = 70Q-Os -4 70(4 0 GPM)- 2 7 ft= 104 ft/day T = 104 ft2/day x 1 gpd/ft - 0 134 ft2/day=774 gpd/ft IS = T(t) - 640 (r0)2 = (104 ft2/day)(60 min) -- (640)(17)2 = 0.034 ' Pump Test No. 2: Q = 6.6 GPM; As = 4.8 ft.; t= 600 minute; ro = 20.5 ft. T = 70Q-As 4 70(6 6 GPM) -4 8 ft= 96.25 ftZ/day T = 96 25 ft2/day x 1 gpd/ft-0 134 ft2/day= 718 gpd/ft S = T(t) - 640 (ra)2 = (96 25 ft2/day)(600 min) - (640)(20 5)2 =0.21 ' Pump Test No. 3: Q = 10.0 GPM; As = 6.3 ft.; t= 100 minute; ro = 24 ft. T = 70Q-As -+ 70(10 0 GPM) --- 6 3 ft = 111 ftZ/day IT = 111 ft2/day x 1 gpd/ft- 0 134 ft2/day= 829 gpd/ft S = T(t) - 640 (rp)2 = (I 11 ft2/day)(100 min) -- (640)(24)2 = 0.03 Pump Test No. 4: Q = 10.0 GPM; As = 3.8 ft.; t= 400 minute; ro = 33 ft. I T = 70Q-As -+ 70(10 0 GPM) - 3 8 ft = 184 ftZ/day T = 184 ft'/day x 1 gpd/ft- 0 134 ft2/day= 1,375 gpd/ft �1 S =T(t) - 640 (ro)2 = (184 ft2/day)(400 min) - (640)(3 3)2 = 0.11 IAdvanced GeoEnvironmental,Inc I