Laserfiche WebLink
APR-05-99 14:14 From:WOODWARO CLYDE + _ T-122 P.Od/OZ !0b-942 <br /> I.INTRODUCTION <br /> a <br /> The purpose of this Chat workplan letter is to conduct additional site investigation and data <br /> evaluation activities in order to complete the Human Health Risk Assessment and Groundwater <br /> Impact at the Shop I0.Maintenance Yard in Stockton, California. The scope of work outlined in <br /> this workplan letter was developed following the February 10, 1999 meeting with the Central <br /> Valley Regional Water Quality Control Board (CVRWQCB) acid the Sart Joaquin County Public <br /> Health Services (S.ICPHS) discussing the draft results of the risk and grourtdwatcr analyses for <br /> the site. <br /> Additional site investigation data and analysis have been requested by the CVRWQC13 to <br /> complete the groundwater and risk analysis. The additional 'site investigation data that was <br /> requested included: <br /> I� <br /> (1) A survey of public and private groundwater wells within 500 feet of Shop 10, <br /> 2 Vertical delineation of petroleum hydrocarbons in oundwater , <br /> (3) Estimation of petroleum hydrocarbon mass in groundwater and soil, <br /> (4) Estimation of hydraulic conductivity,and <br /> (5) Estimation of natural attenuation (degradation)to CVRWQCB Basin Plan concentrations for <br /> maximum concentration levels and taste and odor threshold numbers. <br /> ,r <br /> The additional information will be used in the characterization of the hydrogeology, and fate and <br /> jL <br /> transport of petroleum hydrocarbons in groundwater at the site.'k The additional information will <br /> be used to complete the "Additional Site Investigation, Remedial Options, Human Health, and <br /> ;t <br /> Groundwater Tmpact Analysis Report." <br /> II.SCOPE OF WORKrrECHNICAL APPROACH <br /> Task I.Survey of Public and Private Groundwater Wells <br /> 'i <br /> At the February 10, 1999 meeting, the CVRWQCB requested a survey of public and private <br /> groundwater wells within 500 feet of Strop 10. The California water Service Company, the <br /> Y <br /> primary provider of water to residents in Stockton, had been contacted regarding the water supply <br /> wells in the area. A water well is located approximately 1,000 feet south'of the site that is scmened <br /> 0NCa11T2n1tl31kUVWAF ln?-dOc <br /> p U <br />