WORK PLANS - Laserfiche WebLink

Home Browse Search

Addendum to Monitoring Well Installation Work Plan - December 2007 GREWAL'S MkRIET 4100 East Fremont Street, Stockton, California 1.0. INTRODUCTION At the request of Mr. Rick Grewal of Grewal's Market,Advanced GeoEnvironmental, Inc. (AGE.) has prepared this addendum to Monitoring Well Installation Turk Plan-NovetVher 1999, dated 18 November 1999, for drilling three additional soil borings (P-17, P-1$ and P-f-0) and installing one additional ground water monitoring well (MW-5)at 4100 East Fremont Street, Stockton,California (site).The additional soil borings and ground water monitoring well are being proposed to assess the lateral extent of 1,2-dichloroethane (1,2-DCA)-impacted ground water. The location of the site is illustrated on Figure 1. A plan of the site is illustrated on Figure 2. On 27 June 2007, a meeting was held at the office of the San Joaquin County Environmental Health Department(SJCEHD)to discuss the current site status.During the meeting,the SJCE14D stated that due to the reoccurring detection of 1,2-DCA at well MW-4,that further delineation of the 1,2-DCA ground water plume would be necessary prior to considering this site for closure. The SJCEHD recommended that at least one downgradient ground water monitoring well, and at least two crossgradient soil borings should be installed at the site to further delineate the 1,2-DCA ground water plume. Therefore,this work plan addendum has been prepared in accordance with the above referenced June 2007 meeting, and is also in compliance with a SJCEHD letter directive, dated 16 May 2000. for further ground water investigation. This work plan addendum has been prepared in accordance with guidelines established by the California Regional Water Quality Control Board - Central Valley Division (CRWQCB) for investigation of underground storage tank (UST) sites. Background information and a description of prior investigations at the site were included in Site Conceptual Model, dated 29 March 2004. 2.0. SCOPE OF WORK The lateral extent of dissolved 1,2-DCA must be determined to comply with the above 27 June2007 SJCEHD directive. Based on the soil and ground water data collected during the investigation,AGE proposes to drill and install one additional 2-inch diameter ground water monitoring well (MW-5) screened through first water, approximately between 45 feet and 65 feet below surface grade(bsg); addiionalIy, selected discrete grab water sample (hydro-punch) will be collected from soil borings 1?4� P-0-and P4 at depths of approximately 55 feet,75 feet and 95 feet bsg and within a potential hydrocarbon migratory pathway (i.e. sand unit) to assess shallow, intermediate and deeper 1,2-DCA-impact at the site. Assessment activities will include the following tasks: • Permitting and pre-field work preparations; • Drilling and sampling; Advanced GeoEnvironmental,Inc.