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NOOK FFlRoadEight pplication Permits on file with the San Joaquin County Environmental Health ows there have been no Applications for Repairs/Additions to septic systems within ile radius study area, with particular emphasis to residential structures on Grant Line permits indicating septic system installations are attached to illustrate the dates andms installed. Since the water table is shallow in this area seepage pits or sumps are not allowed. Mr. Pereira stated that there has never been a problem with the septic system of the subject Parcel 1, or with his own septic system. SOIL PROFILE AND PERCOLATION TESTING The soil from 0 inches to 24 inches is uniform and consists of a dark brown clay, with little sand and silt. There is medium organic matter content, and low moisture content. The Unified Soil Classification System (USCS) classifies this soil as CL - a lean clay. From 30 inches to boring termination at 42 inches, exists a light yellowish brown silty clay - classified as a silty clay ML/CL. A Log of Boring designating the USCS soil classification for the percolation test boring is found near the top right-hand corer of the FIELD PERCOLATION TESTING REPORT. Percolation testing was conducted on Parcel "I" near the north side. This location theoretically represents the entire subject Parcel. A shallow,42 inches deep perc test was done because of the high groundwater elevation at approximately 8.5 feet below grade. Pere testing was not done on the Designated Remainder, in accordance with Environmental Health Department regulations. The boring was drilled, scarified and pre-saturated on May 14,the day before testing. Scarification of the boring sidewalls was extremely important in clay type soils. Readings were taken over a four- hour test period to ensure maximum soil saturation under "worst-case scenario" conditions. The perc test exhibited acceptable percolation,but indicated a slowing of the perc rate at the end of the test. This was to be expected given the indigenous clay soils. Without soil scarification,the perc tests would have probably failed. The final perc rate for the last 30 minutes of the four-hour test was 30 min/in, which is half the minimum acceptable rate. The last half hour of the test was witnessed by Steven Shih of the San Joaquin County Environmental Health Department. it7ivla— (id A AJ iA; , 1)j4 LOCAL GROUNDWATER AND SURFACE WATER INFORMATION The 1992 Lines of Equal Elevation Map published by the San Joaquin County Flood Control District is the only recent groundwater map available that illustrates the groundwater elevation in the Tracy area, and therefore the directional flow. It appears, and is generally accepted,that the groundwater is flowing in a northeast direction, toward the Delta. The groundwater gradient can also be assumed by the declination of the land, which groundwater flow typically follows. LAWell er's Log forany nearby domestic wells was not available to denote the underlying soil rched water table conditions cannot exist at higher elevations than the static water table Page -2- Chesney Consufting