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Geweke Property 16 Cherokee Lane, Lodi - 2 - 24 April 2002 and the three CPT logs. At a minimum,wells EX-1,MW-8, and MW-12 must be added to cross-section A-A'. In addition, the geologic units presented in cross-section A-A'have been lumped together as common"sand"units, and must be split out to show higher permeability sand and gravel units, and lower permeability silty sand/sandy silt units. Also, as required by Article 4, Section 2649 of the Underground Storage Tank Regulations, soils presented in geologic logs [and cross-sections] shall be described according to the Unified Soil Classification System(USCS). Please use appropriate USCS symbols and graphics in the cross-sections for this site. 4. AGE recommends installing an additional water table monitoring well near CPT-3 with a 20-foot screen interval. This work in not approved. The CPT report shows that TPHg was identified in deeper water bearing units, and a proposal to verify this contamination was not provided. In connection with comment No.2 above, and prior to our approval to install a water table monitoring well near CPT-3,please provide a proposal to install monitoring wells in deeper water bearing units where TPHg was identified during the CPT investigation. One monitoring well cluster should be installed downgradient of MW-8 along the centerline of the groundwater contamination plume, and another monitoring well cluster should be installed near CPT-3,which is believed to be the leading edge of the groundwater plume. Monitoring well screen intervals must not connect two hydrostratigraphic units, and water table wells must not exceed 15 feet of screened interval (5 feet above and 10 feet below the static water table). The purpose of the December 2001 CPT investigation was to fully define the extent of contamination at the site, such that remedial alternatives can be re-evaluated following the failed in-situ bioremediation program initiated at the site in August 1994. Once additional monitoring wells are installed and the groundwater data for deeper water bearing units is confirmed,we will expect preparation of a site conceptual model and a revised feasibility study to evaluate remedial alternatives for cleanup of the soil and groundwater contamination identified at the site. By 27 May 2002,please respond to the comments above, and submit an addendum to the CPT Report with a proposal for additional work to this office and the County. If you have any questions or comments, please call me at(916)255-31(155. � Marry Hartzell,R.G. Associate Engineering Geologist GCS= 1 - cc: Mr.Mark Owens,UST Cleanup Fund, SWRCB, Sacramento L ' �II Mr. Harlin Knoll, San Joaquin County Environmental Health Division, Stockton A p R 3 0 2002 Mr.Brian Millman,Advanced GeoEnvironmental,Incorporated, Stockton VI S