Laserfiche WebLink
ENVIROkMENTAL HEALTHEPARTMENT <br /> SAN JOAQUIN COUNTY <br /> r Unit Supervisors <br /> Donna�-` K.Heran,R.E.H.S. 304 East Weber Avenue Third Floor Carl Borgman,R.E.H.S. <br /> Director Mike Huggins,R.E.H.S.,R.D.I. <br /> Al Olsen,R.E.H.S. Stockton, California 95202-2708 Douglas W.Wilson,R.E.H.S. <br /> • c •. <br /> Program Manager <br /> Laurie A.Cotulla,R.E.H.S. Fax: <br /> (209) 468-3420 Margaret Lagorio,R.E.H.S. <br /> Fax: (209) 464-0138 Robert McClellon,R.E.H.S. <br /> Program Manager Mark Barcellos,R.E.H.S. <br /> DAVID ATWATER APR 2 7 2004 <br /> VAN DE POL ENTERPRISES <br /> P O BOX 1107 <br /> STOCKTON CA 95201 <br /> RE: CALIFORNIA FUELS STATION CODE: 1214 <br /> 2402 PACIFIC AVENUE <br /> STOCKTON CA 95204 <br /> San Joaquin County Environmental Health Department(EHD)has reviewed GrnundwaierAquiferPumping Test <br /> Report(report) dated February 4,2004 prepared by Advanced GeoEnvironmental,Inc. (AGE). The report <br /> summarized the results of a variable-rate step draw-down pump test at a rate between 3.3 gallons per minute <br /> (gpm) to 4.4 gpm,and a 500-minute constant rate aquifer ground water pumping test at a rate of 5 gpm <br /> conducted on July 9,2003 at the above-referenced site. The drawdownat the extraction well EW-1 was <br /> recorded at 7.71 feet after 500 minutes of pumping at constant rate of 5 gpm,with various draw-down <br /> observed in observation wells AW-1,AW--2,AW-4,1NIW-2 and M\V-3,but no significant draw-down observed <br /> in MW-1. AGE calculated a radius of influence(ROD, of 62 feet at 5 gpm,and a transmisshity value of 565 <br /> square feet/day in an estimated aquifer thickness of 25 feet. Analytical results of the groundwater samples <br /> collected during the pump test were as high as 71,000 micrograms per liter of total petroleum hydrocarbons as <br /> gasc,bric. AGE recommended installation of a groundwater pump and treat system to augment the existing in- <br /> situ air sparging system (IAS),and to specifically address the dissolved contamination located within the <br /> Hydrologic Unit 2 at between 38 and 65 feet below surface grade. AGE proposed submitting a Remedial Action <br /> Work Plan Addendum. <br /> EHD requests submission of additional information that will provide support and rationality for groundwarer <br /> extraction system to remediate the dissolved contamination in groundwater in the Hydrologic Unit 2: <br /> 1. A model of the capture zone for the proposed well and pumping rate,and an updated hydro- <br /> geological cross-section with plume distribution. <br /> 2. An estimate of the contaminant mass that can be addressed through groundwater extraction. <br /> 3. An estimate of the duration of the remediation. <br /> 4, An estimate of the cost per pound of contaminant remediated. <br /> 5. A cost comparison with one,or two other remediation methods. <br /> 6. A justification for the proposed pumping point location,and evaluation of an additional <br /> extraction point near'NRV4. <br /> EHD requests this information be submitted to this office by May 20,2004. <br /> Donna Heran,REHS,Director <br /> Environmental Health Department <br /> c� F <br /> Jeffrey Wong,Senior REHS lfargaretagorio,REHS <br /> LOP/Site'Mitigation Unit Supervisor <br /> c. CRWQCB,Central Valley Region—James L.L. Barton,RG <br /> c: Advance GeoEnvironmental,Inc.—Tim Cuellar <br />