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- r y FLAG CITY CHEVRON Ground Water Pump Test Calculations Assumptions: F • Pump Test No. 1: extraction from EW-2 at constant ground water pumping gate 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 f 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- lo garithmic 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. 1 t=time of pump test ro =intercept of best fit line with the distance axis Pump Test No. 1: Q = 4.0 GPM; As = 2.7 ft.; t= 90 minute; ro = 17 ft. Foe") T= 70Q=0s —4 70(4.0 GPM)_2.7 ft= 104 ft2/day T= 104 ft'/day x 1 gpd/ft- 0.134 ft2/day= 774 gpd/ft I�I FS =T(t) -640 (ro)' = (104 ft2/day)(90 min) -(640)(17)2 - 0.05 1 Pump Test No. 2: Q,= 6.6 GPM; As = 4.8 ft.; t= 600 minute; ro = 20.5 ft. F T = 70QtAs 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=718gpd/ft F S =T(t)-640 (ro)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_= 120 minute; r4 = 24 ft. 4 J T = 70Q=0s -4 70(10.0 GPM)-6.3 ft= 111 ft2/day T = 111 ft/day x l gpd/ft� 0.134 ft2/day=829 gpd/ft S =T(t)—, 640 (ro)2 ==(111.ft2/day)(100 min)-(640)(24)2 = 0.036 �i Pump Test No. 4: Q = 10.0 GPM; As = 3,8 ft.; t= 400 minute;'ro = 33 ft. f T = 70Q=0s -4 70(10.0 GPM) -3.8 ft= 184.ftz/day T = 184 ft/day x l.gpd/ft-0.134 f0/day— 1,375 gpd/ft S =T(t) 640 (ra)2 = (184 ft/day)(400 min) -(640)(33)2 0.11 Advanced GeoEnvironmekal,Inc., I' 1