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0 0 Carollo EngineersGRO November 21, 2006(Project No. 3045.036) - 2.0 WATER LEVEL MEASUREMENT 2.1 SURFACE ELEVATIONS Mr. Kevin Heeney (L.S. 5914) of Cooper, Thorne & Associates will locate the monitoring wells in the field using the information provided on Plate 2. He will survey the elevation of the monitoring wells and the adjacent ground surface to within an accuracy of 0.01 feet relative to the NGVD 29. Mr. Heeney will provide the elevation of the northern side of the PVC casing. He will provide the horizontal coordinates in the California State Plane System, Zone 3. 2.2 WELL CONSTRUCTION A licensed geotechnical engineer will oversee the drilling and sampling of three borings to a depth of approximately 15 feet below ground surface. A well driller with a C-57 Well Drilling License will drill and sample the borings using a truck-mounted rig and hollow-stem augers. The previous investigation indicated groundwater within the upper 5 feet. On this basis, the borings will extend about 10 feet below the groundwater surface. The field engineer/geologist will observe drilling operations and prepare logs of the conditions encountered. The driller will collect soil samples at 3-foot intervals or at significant lithologic changes using a California Modified Sampler with 2.5-inch-outside diameter. Soil from each sampling interval will be screened in the field for organic vapor content using a photoionization detector (PID), and we will examine the soil samples for the typical signs of contamination that include discoloration and odor. The field engineer/geologist will retain the soil samples in 2.0-inch-diameter stainless liners, and seal the liners with plastic caps. If we identify soils that appear to have significant contamination, we will store those samples in cooled ice chest until their delivery to a chemical laboratory. We will request authorization from Carollo Engineers to perform additional chemical testing on the soil samples before conducting any analyses of soil samples. The driller will construct monitoring wells in each of the three boreholes. Soil cuttings generated during drilling will be placed in 55-gallon drums and stored onsite pending the results of analytical testing. 2.3 WELL DEVELOPMENT, WATER HANDLING, AND WATER LEVEL MEASUREMENT Field personnel will commence well development no sooner than 12 hours after the completion of well construction. The field personnel will measure the depth to groundwater with a chalked steel tape or an electronic water level device. The measurements will have an accuracy to within 0.01 feet. The field crew will record the water levels over a 3-hour period of time and record method of water level measurement and the date and time for each measurement. We will continue to take hourly measurements of the depth to the groundwater surface until the water level measurements vary by less than 0.03 feet. G VOBOOCSWO500<50%1FINpL OOCSIRW-2t NOV�DOC 3