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14. PHYSICAL SITE CONDITIONS REPORT Eight exploratory borings were drilled at the site in July of 1993 by RGH (1993). These borings, located along the edge and in the bottom of the quarry, penetrated to depths of from 9 to 25 feet. These existing borings encountered interbedded sand, silt, and gravel, with discontinuous silt and clay layers to a depth of 25 feet. Groundwater was not encountered during drilling. Local water wells indicate that groundwater is present at a depth of approximately 90 feet. The San Joaquin County Flood Control and Water Conservation District maintains an annual record of elevation of water in wells in San Joaquin County. Water at the site stands at elevation 70 MSL, or at approximate depth 90 to 95 feet below the ground surface and approximately 40 to 50 feet below the bottom of the existing pit. Estimated maximum precipitation and projected volume and pattern of runoff for the facility is discussed in Section I.A. of this report and in the Drainage Analysis included in Appendix C. B. MONITORING i t Monitoring for the Composting Facility will consist of 1) sampling and analysis of compost leachate, 2) monitoring of the compost end product to ensure that environmental health standards have been met and 3) monitoring of compost windrows for temperature, moisture, Ph etc. to ensure progress towards adequate material decomposition and fire protection. 1. COMPOST LEACHATE MONITORING All runoff from the concrete compost pad will be diverted via surface swales to an on-site lined evaporation pond and is considered compost leachate. Runoff will be generated from precipitation on the pad and from any runoff from moisture conditioning of material during normal operations although this portion is considered insignificant. One sample of compost leachate will be collected from each of the first five composting batches and analyzed for organo-phosphates, using EPA method 8140, and nitrates. A batch of compost material is considered as a volume equal to,1,000 cubic yards. Records shall be kept which document the source of each composting batch from which compost leachate is sampled. These records and analysis shall be submitted to the Local Enforcement Agency _and Regional Water Quality Control Board if required. If compost leachate fron%&e eve batches of composting material cannot be separated, then one batch sample will be coll=ected from the inlet to the lined evaporation pond. L:/PRO7ECT/397/MRF/RCI4.TCY December 15, 1993 15