Laserfiche WebLink
I <br />' 30 December 2002 <br /> AGE-NC Project No 02-0950 <br />' Page 2of7 <br />' The Modesto, Riverbank and Turlock Lake Formations and overlying Recent alluvium are the <br /> principal sources of domestic ground water in the 13,500-square mile San Joaquin Valley Ground <br /> Water Basin (Basin 5-22) The estimated depth to ground water at the site is 20 feet below surface <br />' grade (bsg) based on information from Lanes of Equal Depth of Water Wells Fall 1999, published <br /> by the San Joaquin County Flood Control District and Water Conservation District- FCD&WCD <br /> Based on the map titled Lanes ofEqual Elevation of Groundwater Spring 1999 also published by the <br />' San Joaquin County FCD&WCD, the site is in an area where ground water appears to be flowing <br /> southwest <br />' 2 2 UNDERGROUND STORAGE TANK REMOVAL <br />' It is our understanding that two underground storage tanks (USTs) were removed from the site in <br /> March 2002 The USTs were reportedly utilized for the storage and dispensing of gasoline and <br /> diesel Concentrations of total petroleum hydrocarbons quantified as diesel (TPH-d), gasoline <br />' (TPH-g), volatile aromatics (benzene, toluene, ethyl benzene and xylenes - BTEX) and total lead <br /> were detected in soil samples collected from the UST excavation <br /> • Based upon the analytical results of soil samples collected during UST removal, the EHD required <br /> the preparation of work plan to define the lateral and vertical extent of contamination in soil and <br /> Iground water <br /> 3.0. PROCEDURES <br /> The field work reported herein was performed in accordance with procedures outlined in the AGE- <br /> prepared Preliminary Sate Assessment Work Plan,dated 13 August 2002,and amended and approved <br /> by the EHD by letter dated 03 September 2002 <br />' 31 DRILLING <br />' On 15 and 16 October 2002, three soil borings B1 though B3 were advanced to a depth of 35 feet <br /> below surface grade (bsg), utilizing a van-mounted Geoprobe 5400 direct-push probing unit <br /> equipped with 1 25-inch probing rods,for the collection and analysis of soil and`grab'groundwater <br /> samples Soil boring BI was advanced in the northwest corner of the former UST excavation <br /> (Figure 2) Soil boring B2 was advanced approximately five feet east of the former UST excavation <br /> Iand soil boring B3 was advanced approximately ten feet southwest of the former UST excavation <br /> i <br /> IAdvanced Gc0$nvironmental,Inc <br />