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WELL INSTALLATION Soil borings completed for well installation will be drilled using hollow -stem augers. The monitoring wells will be constructed with flush -threaded 2 -inch diameter, schedule 40 PVC. The screen slot size will be chosen after completion of the CPT borings and will be based on the grain size of subsurface materials in the screened interval. Well screen placement will also be determined after the completion and review of CPT boring results. The remaining portion of the well will be completed with 2 -inch -diameter schedule 40 PVC flush -threaded casing to the surface. A filter pack will be placed in the annular space adjacent to the well screens and will be installed to approximately 2 feet above the top of the well screens. Approximately two feet of bentonite pellets will be placed above the filter pack. Above the bentonite seal will be a 5% to 10% bentonite -cement grout mixture to ground surface, using a tremie pipe to ensure proper placement of grout material. The well heads will be completed at ground surface with locking well caps and traffic -rated bolt -down well vaults. Each vault will be installed slightly above the surrounding surface grade and finished with a cement apron to provide positive relief away from the wellhead. Soil Sampling Borings will be logged by a SECOR representative using visual and manual procedures outlined by the American Society of Testing and Materials (ASTM) Method D 2488-66T (Reapproved 2000). Soil samples for logging will be collected at approximately 5 -foot intervals using a split -spoon sampler. All soil samples for chemical analysis will be retained in brass, stainless steel, or plastic liners, capped with Teflon squares and plastic end caps, and sealed in zip -lock bags. The samples will be placed on ice for transport to a California certified analytical laboratory accompanied by chain -of -custody documentation. All down -hole drilling and sampling equipment will be steam -cleaned following the completion of the soil boring. Down -hole sampling equipment will be washed in a tri -sodium phosphate or alconox solution between samples. WELL DEVELOPMENT AND SURVEYING The wells will be developed after completion. The development procedure for each well will consist of surging and pumping or bailing water from the well until the water is visibly clear, the well goes dry, or until a maximum of ten casing volumes have been removed. After development, water levels are allowed to partially recover. Groundwater samples are then collected using a disposable Teflon bailer, placed into appropriate EPA - approved containers, labeled, placed on ice, and transported to the laboratory accompanied by chain -of -custody documentation. A California State Licensed Surveyor will survey the newly installed wells. The well casings will be surveyed to the nearest 0.01 feet in elevation to a known benchmark.