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`. %W M KLEINFELDER On October 7, 2003, a representative with our firm obtained samples of groundwater using clean procedures from the main agricultural well near the center of the property. The samples were immediately placed in a chilled cooler, transported to our office, and stored in a refrigerator until they were picked up the same day by Sequoia Analytical using chain-of-custody procedures for DBCP and nitrate (N) testing. The results of the tests and a copy of the chain-of-custody are attached. Groundwater at the site is currently used predominantly for vineyard irrigation and residential uses. We anticipate that the groundwater use would be similar following development. 5. SOIL PROFILE The subsurface conditions at the site were explored at about 2:00 pm on October 7, 2003, by drilling one boring on each parcel to depths of between approximately 5 to 15 feet below existing grade. These locations, chosen by the client, are designated P-1, P-2, P-3, and P-4. These boring locations are presented on the attached map. Due to failing percolation tests, deeper borings were drilled on October 13, 2003, at locations P-1, P-2 and P-3. The soils observed in the deeper borings at locations P-1 and P-2 appeared to be less permeable than the soils observed in the shallower borings drilled on October 7. Therefore, additional test borings were drilled to depths of about 20 to 25 feet at locations P-lA and P-2A on October 13 in an attempt to locate more permeable strata. All borings were drilled using a Simco 2400 truck-mounted drill rig equipped with 6-inch O.D. solid-stem auger. The approximate boring/percolation test locations and approximate dimensions from reference points are presented on the site plan. Based on our findings, the subsurface soil conditions varied significantly across the site. At locations P-1 and P-2, the soils encountered consisted predominately of about 2%2 to 3 feet of clayey silt underlain by silty gravel to depths of about 5 to 7%2 feet below existing site grade. At this depth, an approximate 4-foot thick stratum of cemented, gravelly silt was encountered, underlain by non-cemented sandy clay to the maximum depth explored of 25 feet. The soil conditions encountered in the remainder of the borings varied, with surficial soils varying from silty clay to sandy silt underlain by interbedded strata of sandy and silty clay, clayey gravel, clayey sand, and sandy silt to the maximum depths explored of 15 to 25 feet. A more-detailed description of the subsurface conditions encountered during our field investigation is presented on the attached Logs of Borings. In general, the low-permeable, near-surface silts and clays in the project area do not yield percolation rates meeting SJCEHD percolation requirements. The Soil Survey of San Joaquin County, California published by the US Department of Agriculture, Soil Conservation Service (1992) refers to the near-surface soils within the project area as belonging to the Corning-Redding complex soil series, Redding loam soil series, and Redding gravelly loam soil series (Map Symbols 135, 219, and 220, respectively). The soils are described as having severe percolation characteristics, an available water capacity of 0.10 to 0.16 inches per inch, a pH ranging from 5.1 to 6.5, and an organic content of less than 2 percent. 36600.G01/ST03RI537 October 16,2003 ©2003 Kleinfelder,Inc. Page 2 of 7