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W. r N aquifer thickness at the pumping well and would result in the abnormally large drawdown observed (Krusemann and de Ridder,, 1989). The interpretation of the pumping test data from the site yields the following conclusions: • The aquifer beneath the subject property is heterogeneous, anisotropic and probably unconfined. A typical ;. transmssivity within the shallow zone is approximately ' 1000--8000 gallons per dad* per foot (gp3/ft. ). Typical: storage coefficients within the shallow water bearing zone; (35-50 ft below grade) are 0.005 to 0.01. No aquifer! boundaries are present in the immediate area. • The production well used for testing, MWS, exhibited verb high non-linear head loss-3s. This results in extremely iocr well efficiencies at higher discharge rates. To provide preliminary design specifications for tide rerrediatiou system the theoretical steady state capture zone assoc:isted with various pumping scenarios was calculated. The evaluation wag conducted using the following hydrologic parameters: (1) porosity, n of the saturated sediments is 30-W, (2) the average hydrauli, gradient, i, is ,005, (3) the transmissivi.ty, T, is-3000 gallons per `. day per foot, (4) the hydraulic conductivity, K, of the zone from 35_ to 50 feet below grade is 27 feet per day, and (5) the thickness c,f the saturated zone, b; is 15 feet. -" The presence of gasoline hydrocarbons in the downgradient well EKifL4 suggest the dissclved hydrocarbon plume mayhave migrated sortie. distance off-site in that direction. however, it is not unusual fcx monitoring wells to detect hydrocarbons during initial sampling which c. are introduced by the drilling process. Confirmation sampling will be performed prior to assessing the significance of these levels. The levels of dissolved hydrocarbons drop significantly in thzti ,a downgradient 3irec-cion with concentrations decreasing by over 70$ in t the 50 feet between MW3 and MW4. None of the gasoline constituent' j for which state maximum contaminant levels (MCLs) have beer! established were exceeded in the initial sample from MW4. Although it is not anticipated that contaminants have moved across El Dorado Street this possibility will be addressed after reviewing the ; results of second round sampling. Off-site investigation and/or remediation, if necessary, will be proposed at that time.,: Additionally, there is the potential that other sources of petroleum `, . hydrocarbons are present downgradient of the site. These potential. sources should be considered prior to any off site work. _J websr.Point Property - 475 - H20RAP791.YLP - - 1.