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S mm� <br /> Chevron / pacific Avenue <br /> February 27, 1987 <br /> SITE CONDITIONS <br /> HYDROGEOLO°GY <br /> The general geology in the vicinity of the site consists of <br /> a thick sequence of river channel and flood plain deposits <br /> which consist of inter-bedded sand, gravel, silt, and clay <br /> layers. Several water bearing zones reportedly underlie the <br /> site. The shallowest water occurs at a depth of approximately 45 <br /> feet as recorded in the well on site, the deepest water bearing <br /> zone is more than 1,000 feet deep. The sample at the 14 feet <br /> depth was selected because it was within native material beneath <br /> the tank pit. The material at shallower depths was not tested <br /> because we understand that soil samples were analyzed during tank <br /> pit excavation. The 49 foot sample was selected to document soil <br /> conditions at depth. <br /> soils underlying the pacific Avenue site consist predom- <br /> inantly of intercalated layers of silty and clayey sands with <br /> intervals at clay, sand, and gravel. The water bearing unit was <br /> e^countered under the site at 47 feet, and consists of silty <br /> sand. <br /> SUBSURFACE CONDITIONS <br /> During the drilling of the monitoring well slight to <br /> i <br /> moderate gasoline odors were noted from the surface to 14 feet <br /> below grade. This material was interpreted to be tank backfill <br /> material. Slight gasoline odors were noted from 14 feet to <br /> approximately 39 feet below grade where no further gasoline odors <br /> 7 <br /> E <br />