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Stockton Cineplex Site Work plan for Preliminary Risk Assessment and Contaminant Mitigation Page: 6 Soils at the Stockton Cineplex site consist of interbedded fine sands, silts and clays with occasional carbonate cemented horizons typical of a fluvial deltaic channel, overbank and flood plain environment. The shallow sediments are composed of silts and clays, which grade into fine-grained sands to the depth of the investigation. Perched water is present above a depth of ten feet, limited by weakly cemented sandy silt layer, in borings B-1 and B-2. Unconfined groundwater was encountered at an approximate depth of D feet in borings B-2, B-6, B-8, and B-9 clustered in the northern and northeastern portion of the area investigated. Semi-confined groundwater was present at depth of approximately 17 feet in the southern portion of the site in borings B-1, B-3, B-4, and B-5, confined by a silty clay at a depth of 15 feet. A well-sorted silty unit is present as the confining layer in boring B-1. Groundwater was not encountered until a depth of greater than 20 feet in boring B-7 located in the northwest corner of the site. The site investigation at 222 North El Dorado Street reported groundwater flow to the east. The source of the perched water present at shallow depths in borings B-1 and B- 2 may be due to surface infiltration from seasonal rains and onsite activities. The unconfined to semi-confined water tables present in the fine sand unit at the base of borings B-2, B-6, B-8, and B-9 (water table at approximately 13 feet) and borings 13- 1, B-3, B-4, and B-5 (water table at approximately 17 feet) may be a single continuous aquifer influenced by the semi-permeable clay-silt layer present below ten feet in borings B-1, B-3, B-4, and B-5. 2.0 SCOPE OF WORK A conceptual site mode for the Stockton Cineplex site will be constructed utilizing the existing database of onsite and nearby subsurface investigations. Contaminates of concern will be identified including existing contamination and identification of potential contaminants based on the previous use of the site. A historical summary of the site was presented in the project history. The geology and site soil properties and natural chemistry will be compiled and estimated from the literature and previous studies. Geologic / hydrogeologic cross sections will be constructed and the existing soil and water chemistry integrated into model. Potential receptors in the vicinity of the Stockton Cineplex will be identified including potential onsite and offsite, inhalation, dermal, and ingestion exposures. The effects of potential contaminates of concern will be modeled to predict contaminant concentrations and distributions that will be protective of human health and the environment. The risk assessment modeling will allow for the establishment of site and contaminant specific clean up levels and allow for the preplanning of clean up activities. If a release is encountered the risk assessment model will be recalibrated with site- specific data to establish clean up concentrations. This methodology will allow for the expedited clean up of all potential contamination and the timely completion of the project. A report of the risk assessment modeling will be prepared for submission to the San Joaquin County Public Health Service - Environmental Health Division for acceptance