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Kellogg Garden Products ECOLOGIC Engineering Groundwater Monitoring Well Installation Work Plan KELG04-001 11/10/2004 locations were chosen to provide one up-gradient and two down-gradient monitoring points,based on inferred regional groundwater flow(to the southwest) from the Contact Water Pond(Figure 2).Monitoring well MW-4 will remain and provide a cross-gradient monitoring point from the Contact Water Pond. Table 1 summarizes the proposed actions and well locations with respect to the Contact Water Pond and the regional groundwater flow regime. Table 1: Proposed Well Re lacement Actions Monitoring Well Action Groundwater Well Location Monitoring (with respect to Contact Water Pond MW-1 Conversion to Piezometer P-I GW Elevation Only Down-Gradient MW-2 Conversion to Piezometer P-2 GW Elevation Only Down-to Cross- Gradient MW-3 Conversion to Piezometer P-3 GW Elevation Only Down-to Cross- Gradient MW-IR Proposed Replacement Well MRP Parameters Down-Gradient MW-2R Proposed Replacement Well MRP Parameters Down-Gradient MW-3R Proposed Replacement Well MRP Parameters Up-Gradient MW-4 Existing Well MRP Parameters Cross-Gradient Hydrological Well Design In order to provide monitoring of the uppermost saturated zone and maximize water yield for required laboratory analysis, the monitoring wells should be constructed with the top of the screen about 10 feet below the top of the water table when drilled in the winter of 2005. In order to achieve maximum well utility, the water level in each borehole will have to be closely measured during drilling and before the final well design is chosen. If the wells are drilled at some other time than in the winter, consideration must be given to the seasonal fluctuations at the time of drilling, The monitoring wells will be designed and installed according to the California Well Standards and installed according to the permit conditions of the San Joaquin County Environmental Health Division with the following details: Borehole Diameter — Nominal 8 inches; allows a nominal annular space of 3 inches surrounding the well casing and screen. Borehole Depth — Estimated to be approximately 130 feet bgs based on site depth to groundwater measurements and available borehole logs. Well depth should allow for normal seasonal fluctuations which generally are on the order of approximately+/- 10 feet. Casing Diameter—Nominal 2 inches. Casing Materials—ASTM F480 Schedule 40 PVC. Top of casing shall be approximately two feet above the land surface. Well Screen—Factory slotted ASTM F480 Schedule 40 PVC. Approximately 15 linear feet of well screen will be placed 10 feet below the level at which water is first encountered during the spring. Filter Pack— The wells are proposed using 10-20 mesh Colorado Silica Sand, or equivalent. The proposed monitoring wells are intended for sensitive water quality determinations, therefore all filter pack material shall be handled to avoid contact with contaminants as discussed in Section 11 of the California Well Standards. The filter pack will be extended two-feet above the top of the screen. Slot Aperture Width—Well screens will be installed with 0.020 inch aperture width. The gradation is based on the initial selection of the filter pack and is sized to retain the Dyo of the filter pack. Protective Surface Casing — Six linear feet of nominal 6-inch diameter %-inch wall steel casing, or 6"x6" square tubing, equipped with lockable, removable cap. Cemented in place from approximately 2.0 4