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13 February 2006 Appendix A- Site Background Page 4 of 4 On 10 and 11 October 2005 four on-site ground watermomtoring wells(MW-101 through MW-104) were installed Soil pilot borings MW101 through MW104 were completed as ground water monitoring wells using two-inch diameter PVC casing with 0 020-inch slotted screen installed from approximately 20 feet to 40 feet bsg with blank casing extended to the surface The filter pack(No 3 Lonestar sand) was installed from approximately 18 feet to 40 feet bsg The soil borings advanced for wells MW-101 through MW-104 were comprised of fine-grained sediments and a ground water table within coarse sands Generally brown silty sand was encountered from surface grade to approximately 30 feet bsg A coarse poorly graded sand was present in the soil borings at a depth of 35 feet bsg to 40 feet bsg A silt layer was encountered from approximately 10 to 15 feet bsg in the eastern monitoring well pilot borings Saturated soil was encountered at 30 feet bsg A California state-licensed surveying engineer from Baumbach & Piazza, Inc of Lodi, California surveyed the elevation of monitoring wells MW-101 through MW-104 The elevation at the top of the well casing was surveyed to the nearest 0 1-foot The elevations of wells MW-101 through MW- 104 were determined to be 60 80 feet, 60 72 feet, 57 11 feet and 57 95 feet above mean sea level (MSL), respectively The well were developed and sampled on 17 October 2005 A Solinst water level meter was used to measure the depth to ground water in monitoring wells MW-101 through MW-104 relative to the tops of the well casings, prior to any well purging The ground water elevations and gradient were determined from these data Monitoring wells MW-101 through MW-104 were developed utilizing a stainless steel hand bailer and an inertia pump Ground water was purged from each monitoring well until ground water was visually sediment free Twenty-four to thirty gallons of water were removed from wells MW-101,MW-103 and MW-104,representing ten volumes of the typical well water column purged from the wells, suggesting adequate recharge in these wells Ten gallons were purged from MW-102 before the well was pumped dry, representing approximately four volumes of the water column, indicating low recharge rates in this well The initial depth to ground water during the October 2005 monitoring event ranged from 22 94 feet (MW-103) to 26 56 feet (MW-102) below the tops of the well casings and the ground water flow direction was inferred to be north to northeast Additionally, the data provided from the initial sampling event indicated that VOCs were not detected in the ground water samples from the wells at Ripon Farm Service Additionally,chlorinated pesticides,herbicides,ammonia and nitrates were not detected in the ground water samples collected from monitoring wells MW-101 through MW-104 at RFS The pH values were normal for groundwater in the shallow alluvial areas Advanced GeoEnvironmental,Inc