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04/1912000 02.26 2093671163 FOOTHILL ENGItEERING PAGE 02 This consultamt contacted the City of Lodi to obtain a d scbarge permit to pump the contaminated water from the aquifer into the sanitary sewer and was denied, a permit, The City will not allow the discharge of contamimted water into the sanitary sewer. SITE CONDITIONS AND THE GROUND{Ngl0E AQUIFER In general, all of the soil borings report the same ical characterization of the site. Thesoils above the water table grade fi-om sandy silts to silty clays to depth of forty-five feet below the surFace. The water bearing aquifer begins at forty-five feet below a surface and continues to fifty feet below the surface. Silty clays are directly below the aquifer and eiar depth is unknown. The soils of the aquifer are classified as Clean fine 8mv ty sands. All of the soil borings indicate that the contamination is confined to this five-foot aquifer. True hydraulic gradient of the water table is between S = 0.041 and 0.042 with down slope in the soutb to southeast direction. This aquifer appears to have a high permeability. SCOPE OF WORK It has been determined by this consuhtant that the most ec onomical method of reclamation ofthe property is by the Pump and Treat Method. To co fmn flue possibility of a successful Pump and Treat reclamation Of the aquifer, it is very important to determine the Permeability and Hydraulic Conductivity of the aquifer. Both scan be determined by pump draw down test. The pump draw down test will nm for a duration of eight hours with flow rate and depth to war recorded each hour. Resulting discharge water will be stored on site for mrlamation. The scope of this work plain includes a feasibilfty for th4biamm ediation of the contaminated pump test water. It is estimated the pump test will generate 200 5000 gallons of contaminated water, PROCEDURE Extraction Well Installation An extraction well is to be installed at the location she diameter well is to be drilled with a hollow stem ai approxima*ly fifty-five feet below the =5ce. At i arson sampler. This sample will be alyzed by EPA on the attached site drawing. The ftfteenanch to a depth of five feet below the aquifer or depth a soil sample will be taken with a split [hod 8260B. A six-inch PVC casing will be installed with ten feet of screen (see extraction well detail attached.). A number #lace sw)d filter is to be installed to two feet abov the screened casing. A two -foot bentonite plug will be placed above the sand filter. Cement grout shall placed from the bentonite plug to the reface. The well is to be developed after the grout is in place. Test Prooedure A well pump with a capacity greater than ten gallons per to the bottom ofthe casing. The pump shall be equippec flow We and total volume. The #law rate will be record hourly thereafter until the end of the test period. A water stream at the begurniog of the test period and at the end Soundings to the groundwater surface shall be tAen 2 n.inute at seventy feet of head is to be installed with a flow meter that records volume in both .d at ten minute intervals for the first hour and sample will be taken from the pump di sr arge A the test periled.. in all monitoring wells.