WORK PLANS - Laserfiche WebLink

Home Browse Search

• • 'Clayton y � GAp VI SEPV ICES utility locator to screen the well locations for underground utilities. Clayton will not advance a well boring within three feet from a known underground utility. 5.1.2 Monitoring Well Construction Clayton proposes to install five 2.0-inch diameter groundwater monitor wells on and in the vicinity of Parcel 2A using a California State Water Well C57-licensed contractor. The monitoring wells will be installed utilizing a truck mounted hollow stem auger drill rig. All hollow stem auger drill stems and downhole sampling equipment will be either steam cleaned or washed in a solution of non-phosphate detergent and double rinsed with tap water after each use. As required by California Code, a 2.0-inch annular space between the outside of the monitor well casing and borehole will be provided during construction. To achieve this, 8-inch outside diameter augers will be used. The wells will be constructed of 2-inch diameter schedule 40 PVC casing with flush threaded joints. The screened section will consist of 0.020 inch machine cut slots. A six inch bottom cap will be placed at the bottom of the well. The screen will be a 15 foot section and extend above the soil/water interface. The screened section will extend approximately five feet above and ten feet below the water table at the time of drilling. The screened section interval will vary by location as the depth to groundwater at the Site varies by approximately eight feet across the Site. Blank casing will be installed above the screened section and extend to the ground surface. The annular space around the screened section of the well casing will be filled with a 2X12 sand pack which will extend two feet above the top of the screened section. A two foot bentonite seal will be place over the sand pack, and the remaining annulus will be filled with neat cement, extending to the ground surface. A lockable expanding well cap will be used to secure each well head. Completed well construction diagrams will be submitted to the appropriate regulatory agencies after the completion of the field activities. Depending on the location of the well, either a traffic-rated vault box or a stovepipe type risers will be installed. Each new well will be clearly identified as a monitoring well on the well lid or well riser. Pending results by laboratory analysis, the soil and water generated during drilling will be placed into DOT-approved drums, labeled with the name of the site, address, well number, sampled, and left at the site pending profiling for off-site disposal. 5.1.3 Soil Sampling and Analysis Soil samples for logging, headspace analysis, and laboratory testing will be obtained in _clean, 2-inch-diameter, 6-inch-long brass tubes using an 18-inch California modified — split-spoon sampler, which is driven into undisturbed soil ahead the auger bit. The sampler is advanced utilizing a 140 pound hammer with a 40 inch drop. Blow counts will be recorded for each 6-inch driving interval, and the blow counts for the final 12 inches will be recorded on the boring log. As the majority of the wells are intended to PL.\ESPROJEC S%ZW1WYW29 U.a Lincoln and W,be ,kPIND _I%wkpin .OZ)W