ARCHIVED REPORTS XR0012868 - Laserfiche WebLink

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Refer to PLATES I & II and prior reports for details ' REGIONAL GEOLOGIC & GEOMORPHIC PROVINCE Refer to PLATE III and prior reports ' SOILS CLASSIFICATION: j Refer to prior reports for a soils profile map and additional I details I DEPTH TO GROUNDWATER During excavation work conducted in May, 1993 , groundwater was encountered at about 35 ' bgl Groundwater was observed entering ' the excavation during the work performed in December, 1994 Water level measurements from the monitoring wells in July & December, 1995 averaged slightly below 24 ' bgl Measurements ' taken in April, 1996 revealed an average depth to water of 20 44 ' bgl During the 7/29/96 sampling it had dropped slightly to 20 83 'bgl, and to 21 26 ' bgl on 9/16/1996 LOCATION OF NEARBY WELLS : In addition to the eight (8) wells currently on the site, and the one recently placed at 1245 W Charter Way, records show over 20 groundwater monitoring wells in the immediate area There are no commercial water wells in this region due to the fact that the ' deeper aquifers have been infiltrated with salt water and are not potable BRIEF REVIEW OF PRIOR WORK DONE ON SITE ISeptember, 1992 - Septic tank serving shop building taken out of service ' November, 1992 - Septic tank & leach lines uncovered Found to contain waste oil & petroleum products ' May, 1993 - Septic tank emptied & leach field removed Wooden septic tank also removed Excavation left open. ' August, 1993 - Five (5) auger borings placed in area of leach field to depths ranging from 32 ' bgl to 42 ' bgl , the presence of petroleum hydrocarbon substances was detected in soil & ground- water Three (3) hand-auger borings were placed in and adjacent to the site of the removed leach field, refer to prior reports for complete details TABLE I summarizes the results of labora- 2 1