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RA <br /> , M�-, <br /> NO` fir' s y <br /> r= <br /> y <br /> PROGRESS REPORT/REMEDIATION FEASIBILITY STUDY <br /> Holt Brothers <br /> 1541 West Charter Way <br /> Stockton, California <br /> (Figure 1) <br /> In May of 1988, seven 7 <br /> ) underground storage tanks removed from the site. During removal of he UST's (avidence were <br /> soil contamination was noted. The initial investigation work <br /> conducted by Dames <br /> installation & Moore of four (4) monitoring wells JanualY 1989), Included the <br /> Sol' samples Collected from ted soil(MW1, law2,contaminatiMW3, and MW4). <br /> contamination of soils was found during he Installation ofon. sNo <br /> ;,'12, N.W3, or MW4. Groundwater sam ' <br /> Ales collected from wells M W31end <br /> contained petroleum hydrocarbons, and !'alo enated <br /> orfk <br /> danhydrocarbons. Halogenated organics were not found ointMw3 <br /> ic <br /> Pnac� II site, investigations (September of 1989) conducted b 8 <br /> National Corporation in conjunction with Dames � <br /> the drilling of five Moore, included <br /> (51 soil borings with the completion of two <br /> (2) borings as monitoring wells (MWS and MW6 <br /> 1310 National Corporation installed a cycle In December of 1989 <br /> prototype biologic treatments stem o Pump and <br /> On Januar <br /> y operating on effluent from Mwl. <br /> Y 4 eratin 1991 WaterWork Corp. performed a short term step <br /> drawdown test and longer <br /> using wall Mwb. Dariterm (4 hr) constant rate <br /> During the test, drawdown in wells pumping test <br /> MW6 were monitored. The step drawdown test was performed to <br /> evaluate thee, MWS, and <br /> determine thepo odsctivity and efficiency of the well, and (2)(lto <br /> F lmsm rate for the longer term constant rate test. <br /> The step test indicated the well does not exhibit si <br /> losses and is reasjnably efficient. The semilo y gni£icant well <br /> test data is contained in Attachment 1, 9 Plot of the step <br /> A rate of 1.5 gallons <br /> er minute (gpm) was selected for the longer <br /> term constant rata test. <br /> W8118 MWl• MW5 and MSemilog plots of drawdown versus time for <br /> the semilog pl , W6 are contained in Attachment i along :pith <br /> ot. of the .recovery data from well MWS. <br /> transrnissivitl► and storage coefficient calculated The formation <br /> data are shown on Table 1. from the test <br /> Interpretation of the monitoring well data is cam 1� <br /> by the effects of partial penetration. Because MW6�istscreened In <br /> sand 5-8 feet deeper than wells MW1 a:�d �ytl5 (Table 1 ed ixx <br /> communication is potentially limited particularly fore hydraulic <br /> logs indicate a well, MW5, was drilled and sandpacked to a depthof <br /> 45 feet although casing extends only 37,5 ft. The uncased but <br /> siat.Riax.vp <br /> 1 <br />