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' 0 k'■ KLEINFELDER TWA from 60 feet bgs to approximately 64 feet bgs. Sand was seen in the boring to approximately 83 %2 feet bgs. Sandy silt was encountered to approximately 111 feet bgs. The sandy silt was yellow brown, very dense, and slightly moist to 95 feet bgs. The drilling rate was noted as faster at 90 feet. At 95 feet the soil was noted as having a cemented nature to the ' sample collected, although still being classified as sandy silt. The soil color changed from yellow brown to red brown at approximately 105 feet. At approximately 111 feet bgs sandy clay (CL) was encountered in TWA. The clay was yellow brown, moist, hard, and trace sand accounting for a small percentage of the sample collected. The sand consisted of fine to medium ' sand. The sand content was found to increase with depth to the completion of the boring at approximately 121 feet bgs. No adverse odor or staining was observed in ,the soil samples collected during the advancement of the boring at location TW-1. The second deep soil boring (TW-2) was drilled in the area of the proposed 72 million gallon ' pond. TW-2 was drilled to a total depth of approximately 26 %2 feet bgs. Groundwater was encountered at approximately 6 Meet bgs and rose in the boring to approximately 5 feet bgs. ' Silty clay was seen in the TW-2 soil sample interval of 5 feet bgs. The 10-foot sample interval ' appeared to be sandy silt, dark yellow brown, medium dense, and fine grained. At approximately 18 feet bgs sandy gravel, with fine to coarse sand, and up to %2-inch diameter gravel was ' encountered. A gray brown, dense, clay was encountered at 21 feet bgs. TW-1 was advanced an additional 5 %2 feet to a total depth of 26 %2 feet to assure that the clay layer was sufficiently penetrated. TW-2 soil boring was stopped at this point to avoid the possibility of breaching two ' aquifers. Two soil samples were collected from each deep soil boring for geotechnical analysis. The RWQCB C & A Order required a minimum of two soil samples consisting of clay aquitard ' material be collected for analysis from each deep boring. ' The soil samples submitted for geotechnical analysis from TWA were collected from the 60 to 120 foot depths. Soil samples from TW-2 were collected from a depth of 5 and 26 %2 feet bgs. The soil samples were analyzed for hydraulic conductivity using a flexible wall permeameter and ' grain size distribution analysis. Two soil samples collected from TW-1 were analyzed in an undisturbed state. The soil samples selected for analysis were collected from the 60-foot and 120-foot intervals. The soil sample collected from the 60 foot interval displayed a permeability of 8.02 x 10-5 (cm/sec). The 60 foot 20-2594-01004/2011 R447 Page I 1 of 16 Copyright 2001 Kleinfelder,Inc. June 8,2001