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and will be free of organic matter, clay balls, and other deleterious substances. Sand material used in the pack around the well screen will be selected to be compatible with both the screen slot size and aquifer materials. Based on the 0.020-inch slot well screen, the anticipated filter pack size will be equivalent to 8 x 12 Silica Sand or RSI No. 3 sand. The filter pack size may be modified based on the results of the formation sample sieve analysis. The pack will have a uniformity coefficient less than 2.5. The pack will be properly cleaned and bagged by the supplier. The filter pack will be installed a minimum of 6 inches below the screen, and from 2 to 5 feet above the screen. A 5-foot bentonite seal will be placed on top of the pack material. The bentonite seal will be composed of high quality bentonite pellets, as manufactured by Volclay or equal. Unchlorinated water will be added to ensure that the pellets expand to form a tight seal. Properly wetted bentonite pellets are the most time-effective form of bentonite for this application. A bentonite-cement grout seal will extend from the top of the bentonite seal to the land surface. Bentonite powder will be mixed with water before the cement is added to the mix. Grout may be mixed at the well site by the contractor, or purchased from a ready mix supplier,provided that the supplier can provide current water quality analyses showing the mix water to be free from VOC, chlorine, inorganics, or other sources of contamination. The grout will be pumped into the annular space under pressure using a tremie pipe placed at the top of the bentonite seal to ensure a continuous grout seal. The protective casing will be set in the grout. Grout will be left undisturbed for 24 hours after placement. After the grout seal has set, it will be checked for settlement, and additional grout of approved composition will be added to fill any depressions. As indicated previously, the County will be contacted for the well seal inspection. Grout will be composed by weight of 20 parts Portland cement to 1 part bentonite, with a maximum of 10 gal of approved water per 94 lb bag of cement. Bentonite powder used in the seal will be a commercially available product designed for well sealing. Overall, the percentage of bentonite in the bentonite-cement grout will not exceed 5 percent by volume, to prevent excessive shrinkage of the cement mix. 3.3 Well Protection Because the monitoring wells will be located within the golf course area, it is proposed that they be constructed with above-ground completions. Above-ground completions will consist of a 4- inch protective casing installed at the well. This protective casing will extend approximately 2 feet above the ground surface and 3 feet into the well seal grout. The protective casing will be vented to the atmosphere by a lockable, hinged cap. The cap will prevent entry of water but will not be airtight, so the well will be in open connection to the atmosphere to allow for water level stabilization. The hinged cap will be locked with a heavy-duty padlock. The top of the well casing will be a minimum of 4 inches below the protective casing cap. In addition, a '/4 inch diameter drainage port will be installed centered 1/8 inch above the level of the concrete pad. A square concrete pad will be placed at the monitoring well site, with the well located at the center of the pad. The pad will measure 3 feet by 3 feet, and will be 6 inches thick. The pad will contain welded wire fabric (No. 10 wire) at middle depth throughout. Four 4-inch diameter, French Camp-Monitoring Well Installation Workplan 4 SAB027100 September 2006 CADocurnents and Settings\nnlagorio\Local Settings\Temporary Internet Files\0LK9F\Work Plan