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i On January 24, 1997, our representative returned to the site to perform the percolation tests. The tests were performed according to San Joaquin County guidelines for a period of 4 hours. The Iast 30 minutes of each test were used to calculate passing percolation rates of 2-112 and 4 minutes per inch for tests. P-3 and P-4, respectively. The County approved percolation test sheets are included with this report. I Item d_3: "The depth and gradient of the water table;" I During our site visit on January 14, 1997, we were not able to measure groundwater in the wells located on the property. The regional groundwater depth map published by the current San Joaquin County Flood Control and Water Conservation District report, Plate 2, does not indicate the depth to groundwater in this area. However, information contained in the report for a well located approximately 2 miles east of the site indicates groundwater was at approximate elevation 74 feet in spring 1995. This would be approximately 50 and 95 feet below the ground surfaces of the north and south edges of the subject property, respectively. Based on the County requirements for.a parcel split project such as this, we are not required to establish an on-site groundwater gradient by drilling borings. The County groundwater map showing lines of equal elevation of groundwater, Plate 3, does not indicate a groundwater gradient in this area. In our opinion, the likely groundwater gradient would be in the east-northeast direction toward the San Joaquin River, unless significant drawdown from adjacent wells was to occur. As requested by San Joaquin County Environmental Health in their Conditions of Approval," , we collected water samples from the domestic well located at the residence on proposed Parcel 1. The samples were delivered to Sequoia Analytical laboratory in Sacramento for DBCP and nitrate content testing. The test results from Sequoia Analytical are included with this report. We note that our scope of services did not include a detailed evaluation of the potential for the septic systems to affect the quality of the groundwater. However, the project involves the I possibility of only four additional septic systems within the approximate 277-acre property. Therefore, with groundwater depths estimated at approximately 50 to 95 feet deep, in our opinion the likelihood of a significant change in the nitrate level of the groundwater beneath the site, because of four additional septic systems, is very remote. This completes our scope of services at this time. Based on the above information, it is our opinion that the four proposed parcels are suitable for septic system use. Any new or replacement septic systems should be located and any future wells should be constructed following County requirements. Continuous monitoring of the on-site septic systems should be maintained throughout the duration of their use. Once this report is reviewed by Environmental Health Services, we will be pleased to furnish a proposal for providing whatever additional information they may require for their evaluation. 20-2250-07.GOi/207RG025 Page 3 of 4 January 27, 1997 Copyright 1997 Meinfelder, Inc. KLEINFFLDER 2825 East Myrtle Street, Stockton, CA 95205-4794 (209)948-1345 (209) 948-0621 fax