ARCHIVED REPORTS_XR0012251 - Laserfiche WebLink

Home Browse Search

Historical Background AGE-NC Project No 00-0764 ' Page 3 of 3 GROUND WATER MONITORING WELL INSTALLATION I ' On 13 and 14 August 2002, five ground water monitoring wells were installed near the UST area (MW-1 though MW-5)to quantify the hydrocarbon concentration in ground water and determine the ' direction of ground water flow Field work was performed as described in the AGE-prepared Monitoring Well Installation Work Plan, dated 08 July 2002, as amended and approved by the San I ' Joaquin Country Environmental Health Department (EHD)by letter dated 18 July 2002 MW-1 through MW-5 were completed as ground water monitoring wells with slotted screen ' installed from approximately 15 to 35 feet bsg in bonngs MW-1 through MW-4 and from approximately 69 to 74 feet bsg in boring MW-5 Locations of the monitoring wells are illustrated on Figure 2 of the report Results of the well installation and subsequent sampling delineated the dissolved hydrocarbons and Indicated direction of ground water flow generally towards the northeast Ground water monitoring ' enabled delineation of the dissolved hydrocarbon plume The dissolved hydrocarbon plume has been vertically delineated Analytical data is presented in the attached tables ' • STRATIGRAPHY AND DEPTH TO GROUND WATER Silt, with a tan, brown or gray color, apparently depending on hydrocarbon impact, was generally ' encountered from a depth of approximately 5 feet to 35 feet bsg in the shallow well borings, the p pP y g coarsest material was silty sand, collected at a depth of 25 feet bsg in boring MW-2 Silty sand was ' generally encountered to a depth approximately of 40 feet to 45 feet bsg Generally poorly graded sand and silty sand was encountered between 60 and 75 feet bsg in boring MW-5 Ground water was encountered at a depth of 30 feet bsg during drilling 1 1 ' Advanced GeoEnvironmentai,Inc