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E (§ 4.0) LOCAL GROUNDWATER INFORMATION r7((S§ 4.11) The 1999 Lines of Equal Depth Map and the 2003 Lines of Equal Elevation Map published by the San Joaquin County Flood Control do not illustrate the groundwater depth or flow direction for the Delta area since the water table is extremely shallow and variable. It can be reasonably concluded that the groundwater flows toward and away from Old River, although very slowly. These inflow and outflow conditions are dependent upon tidal action and/or heavy river flow conditions. No domestic wells are on this Parcel. Therefore, Sections § 4.3, 4.4, 4.5 and 4.6 are not applicable. (§4.2) Due to the proximity of Old River, the River will substantially influence groundwater elevation and quality. It has been observed throughout the County that typically there is very low, or nonexistent nitrate concentrations in wells and/or the water table next to rivers. Percolating effluent that reaches the water table will most likely undergo a dilution effect from the River's influence. As referenced, it is typically in the Conditions of Approval directive that EHD requires the depth to groundwater be determined. A backhoe from C.C.R.C. Farms was used to excavate down to the water table. A total depth of 10 feet was excavated on February 13, 2006, 1030 hrs in an area directly adjacent to the southeast of the proposed disposal field. On February 14, 2006, 1400 hrs, the depth to the water table was measured with an electronic water level meter to be approximately 7.5 feet below existing, surrounding grade. Considering the intense rainfall that occurred during the months of December and January in this location, the water table would have been thought to be much higher in elevation. (§ 7.0) CONCLUSIONS (§ 6.8) The 42-inch deep percolation test results for the proposed disposal area show excellent percolation for the management of the anticipated septic system effluent flows in the leachline trenches from the proposed two bedroom - one bath, Manufactured Unit#4. The 24-inch deep percolation test boring and the Double Ring Infiltrometer test reveal substantial soil compaction at the approximate 24-inch depth below grade, thus precluding the installation of a filter bed. This was to be expected given the importation and compaction of favorable soil material to raise this area, along with additional soil compaction that has occurred when equipment such as fork lifts were used to deposit the referenced discards. These discards will obviously be transported off-site so that the septic system, leachfield and 50% reserve area can be constructed. This area must be maintained and protected so that it cannot be driven over, parked on, or used for storage. The Profile View schematic illustrates the septic system as proposed, along with operational parameters. In summary, influent will gravity flow from.Unit#4 across the levee road and down the referenced embankment into a 1200 gallon, two compartment septic tank. Effluent from this tank will gravity into a Distribution Box, then gravity into three, 75-foot long leachlines. Page -5- Chesney Consulting