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Soil Borings Three soil borings were performed on the project site; the approximate locations of the borings are indicated on Figure 3. Borings B-1 through B-3 were advanced to a maximum depth of 16.5-feet, with soil samples recovered at depths of 2.5, 3.5, 5.5, 7.5, 10.5, and 15.5-feet. Groundwater was not encountered in any of the borings during drilling operations. The borings were drilled by Spectrum Exploration, Inc. , a State of California licensed drilling contractor (License No. 512268) . The borings were advanced using a six (6) inch, nominal diameter, continuous flight hollow stem auger. Soil samples were obtained using a 2-inch I.D. split barrel sampler. The sampler was advanced into the soil ahead of the auger by a 140-pound hammer repeatedly falling 30 inches. Pre-cleaned brass liners were placed in the sampler to retain the soil. The blow counts necessary to advance the samplers were recorded for each 6-inch interval. The borings were logged under the supervision of our field engineer. Following the completion of the drilling, the boreholes were grouted. The drill cuttings and soil samples obtained from the borings were monitored during drilling for evidence of hydrocarbon content, and to observe moisture changes. Drilling and sampling equipment used for advancing the exploratory borings was thoroughly steam cleaned before drilling began to prevent introduction of off- site contamination and between each boring to prevent cross contamination between borings. Sampling equipment was cleaned between sample events by using a phosphate-free detergent bath and double rinse to prevent cross contamination. Pre-cleaned brass liners were placed into the samplers to retain the soil samples. The drilling and sampling equipment was steam cleaned subsequent to the completion of drilling activities. Soil samples were collected in 6-inch by 2-inch diameter and 4-inch by 2-inch diameter brass sleeves. The sleeves were sealed using teflon and plastic end caps, and tape. Labels indicating the date, time, sampling location, and project number were affixed to each sample. Soil samples were stored on ice and transported under chain-of-custody within 24 hours of collection, to Western Environmental Science And Technology, a California State Certified Laboratory. VI. SUBSURFACE SOIL CONDITIONS The borings encountered an approximate 9-inch thick pavement section consisting of asphaltic concrete over an aggregate base. Below the pavement section, the subsurface soil conditions revealed by the borings may be generalized as consisting of the following: • Surficial Layer - This layer consisted of dark gray/dark brown silty clay of medium to high plasticity. This layer was encountered to an approximate depth of 3 feet. • Clayey Soil Layer - This layer consisted generally of brown, low plasticity sandy clay and/or fine-grained clayey sand. This layer was encountered to depths of 10 to 14 feet. • Sand Layer - This layer consisted generally of brown to brown-gray, fine to medium-grained sand and/or silty sand. This sand layer was encountered to the maximum explored depth of 16.5 feet. Groundwater was not encountered in any of the exploratory borings during drilling operations. - 3 -