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Pombo Property Excavation and Monitoring Well Installation investigated to a maximum thickness c f 5 feet and will be backfilled with concrete slurry, after a Bentonite seal has )een placed. If a deeper aquifer is to be investigated, conductor casing will first bt grouted into place to seal off the upper aquifer(s), in series, if necessary, and dril ing will proceed through the conductor casing after the grout has been allowed to set properly. If evidence of contamination is noted during the drilli g, the drilling will be halted until the responsible professional determines the advisability of deeper drilling. Upon termination, the boring into the aturated zone will be completed as a monitoring well and backfilled with concrete grout, after a Bentonite seal has been placed. The boring for the monitoring well will be of a diameter at least 4 inches greater than the 2-inch diameter of he well casing to be used. The cuttings from the drilling operation will be containerized on-site during drilling for proper disposition. The proper method of disposal will be dependent upon results of laboratory analysis. This disposal will be the responsibility of the client unless other arrangements are made. 2.2 Well Construction All materials used in well construction will be thoroughly cleaned prior to introduction into the boring. A Bentonite or cement and Bentonite grout will be placed at the bottom of the boring as net scary. After the seal has been allowed to set long enough to support the weight of the casing, a 2- inch diameter well casing (PVC) with end cap and factory pe forations for placement in the saturated zone (taking into account seasonal variation) will be placed in the boring. The screen and filter pack sizes will be as noted in the well construction. The casing and end caps will be threaded or joined by stainless steel screws; no PVC cement will be used. The filter pack will extend two feet above the perforated zone. A Bentonite seal 2- to 3-feet thick will be placed in the annular space above the filter pack followed by a cement grout to the surface. Seal and filter pack elevations may change based on the underlying geology. 2.3 . Well Development and Sampling The well will be developed until the well water appears clear of sediment, or until an appropriate number of well volumes (based upon the judgment of the responsible professional) have been evacuated. A minimum of 50 gallons will be produced f rom t he d eep w ell d uring d ev lopment. T he w ater p roduced d uring well development will be contained and di posed of by the driller. The wells will be allowed to stabilize for twenty-four (24 hours prior to sampling. All soil and groundwater samples will be properly labeled with date collected, project number, sample coordinator, and sample identification. Field records will document the above information and other significant data, such as names of on- 8