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Meeting Minutes for Stockton Former MGP Site Project <br /> August 28, 1996 <br /> Offices of DTSC, Sacramento <br /> 1.0 Objectives <br /> Paula Bolio reviewed the objectives of this meeting. They were to 1) discuss the sensitivity <br /> analysis and input parameters for the VLEACH model and the groundwater mixing cell <br /> model, 2) discuss the results of preliminary VLEACH modeling, 3) discuss other future <br /> model runs and VLEACH application during the FS, and 4) discuss and agree on soil data <br /> needs and status of source area definition in Area I. <br /> 2.0 Sensitivity analysis/input parameters <br /> Paula Bolio reviewed the sensitivity analysis that had been performed for the VLEACH <br /> modeling discussing 1) the vertical and aerial discretization of soil data within the VLEACH <br /> model, 2) the soil and chemical input parameters into the VLEACH model, and 3) the <br /> assumptions behind the groundwater mixing cell. <br /> There was agreement from everyone that the aerial discretization of polygons around <br /> existing borings was satisfactory. <br /> Marvin Woods agreed that the vertical discretization of soil data benefited conservative as <br /> well as nonconservative ways of viewing the data. <br /> The input parameters that were discussed for the purpose of conducting a sensitivity analysis <br /> were groundwater recharge rate, Koc, Foc, volumetric water content, and total porosity. <br /> With respect to groundwater recharge it was understood by the group that the site is and will <br /> be paved. Paula Bolio described the basis behind the recharge rate chosen for the site. Deed <br /> restrictions were discussed with respect to future residential buildings and providing for a <br /> paved surface. Philip Isorena mentioned that we should take into account the possibility of a <br /> sewer line break beneath the surface. Fritz Carslon replied that some of these scenarios were <br /> unlikely, or would take place on a very limited scale or timeframe. It was agreed that water <br /> and sewer line locations would be identified so as to determine if these lines exist near the <br /> source areas. Marvin Woods agreed that the base infiltration rate was reasonable but that a <br /> model run should be conducted with a doubled infiltration rate. <br /> Marvin Woods agreed that the values used for Koc were reasonable and there was no need <br /> to vary them further. <br /> Marvin Woods wanted to see the distribution of site soil data that was used for Foc, <br /> volumetric water content and total porosity so that each parameter value chosen for the base <br /> case could be justified based on its distribution. <br /> 1 <br />