WORK PLANS - Laserfiche WebLink

Home Browse Search

Attachment A Geosyntec Consultants Monitoring Well Installation and Development Procedures OVERVIEW Following California Regional Water Quality Control Board, Central Valley Region (RWQCB) acceptance of the proposed well location, monitoring well DMW-513 will be drilled and installed within the B-zone aquifer, located approximately 50 to 75 feet below mean sea level, corresponding to 60 to 85 feet below ground surface (ft bgs). A single two-inch diameter groundwater monitoring well will be installed. As part of this task, Geosyntec will perform the following activities: • Mark well location and arrange for permitting and underground utility clearance; • Update the project health and safety plan, as necessary; • Drill and install the monitoring well; • Survey the well; and • Develop and sample the well. These activities are described in detail below. Well Location,Permitting, and Underground Utility Clearances Geosyntec will visit the Site to mark the well location for underground utility clearance and notify Underground Service Alert (USA) a minimum of two business days before drilling. The well location will also be cleared by a private utility locator. Geosyntec will obtain a well permit from the County prior to drilling and well installation. The County and RWQCB will be notified 5 days in advance of the scheduled well installation. Drilling and Installation of Groundwater Monitoring Wells The well will be drilled and installed by Gregg Drilling and Testing, a licensed California C-57 drilling contractor. All downhole equipment will be cleaned before use at the Site. Using mud i rotary, a 10-inch diameter steel conductor casing will first be drilled and installed to approximately 50 ft bgs. The conductor casing will be grouted in place. After the grout has set, 8-inch diameter hollow stem augers will be used to advance the boring through the conductor casing to the total well depth. A Geosyntec California Professional Engineer or Geologist will ! provide oversight of the drilling operations and well installation. The well will be continuously logged from 50 ft bgs to the bottom of the boring to obtain geologic information. Soil cuttings will be contained in 55-gallon drums. Soil samples will not be collected for chemical analysis unless unusual soil conditions are noted during drilling. i The following general procedures will be followed in constructing the monitoring well. After reaching total depth in the boring, well construction materials will be placed through the center Page 1 of 4 January 2014