Laserfiche WebLink
Table 16CDCR-EW-4 Hydraulic Capture EstimationWell Installation and Interim Remedial Action ReportCalifornia Department of Corrections and RehabilitationStockton, CaliforniaTest Pumped WellPumping Water-Bearing ZoneSaturated Thickness (ft)Transmissivitya (T) (ft2/day)Hydraulic Conductivity (K) (ft/day)Hydraulic Gradientb (i)Pumping Rate (Q) (gpm)Pumping Rate (gal/day)Pumping Rate (ft3/day)USEPA Radius of Capturec (Ywell, ±ft)USEPA Well Capture Width (ft)USEPA Maximum Radius of Captured (Ymax, ±ft)USEPA Maximum Upgradient Capture Width (ft)USEPA Downgradient Capturee (X0 ft)10.0 14,400 1,925 32 64 64 128 2015.0 21,600 2,888 48 96 96 192 3117.5 25,200 3,369 56 112 112 224 3620.0 28,800 3,850 64 128 128 257 41Notes:a Aquifer transmissivity calculated from monitoring well data from CDCR-EW-4 constant rate test.b Hydraulic gradient calculated using transmissivity, and average groundwater flow which varies from 0.001 up to 0.003 depending on the season.c Lateral plume capture from well location per USEPA (2008) capture zone evaluation guidance [Ywell = ±Q/4Ti].d Upgradient maximum lateral plume capture per USEPA (2008) capture zone analysis [Ymax = ±Q/2Ti].e Downgradient maximum plume capture per USEPA (2008) capture zone analysis [Xo = Q/2πTi].Capture zone method from USEPA 600/R-08/003Where:Q = DischargeT = Transmissivity i = Hydraulic gradient ywell = Width of capture adjacent to the extraction wellymax = Maximum upgradient capture by the extraction wellX0 = Stagnation point downgradient of the extraction wellAcronyms and Abbreviations: ± = plus or minus ft3/day = cubic feet per dayCDCR = California Department of Corrections and Rehabilitation gal/day = gallon per dayft = feet gpm = gallon per minuteft/day = feet per day USEPA = United States Environmental Protection Agencyft2/day = square feet per dayReference: USEPA. 2008. A Systematic Approach for Evaluation of Capture Zones at Pump and Treat Systems. EPA/600/R-08/003, 2008. January 29. Available online at: https://cfpub.epa.gov/si/si_public_record_report.cfm?Lab=NRMRL&dirEntryId=187788.0.002CDCR-EW-4Shallow / Intermediate Groundwater Zone30 7,505 250TiQywell4TiQy2maxTiQx20Page 1 of 1