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r7C. PERCOLATION TEST RESULTS SSS§ 6.2. To assess the permeability of the proposed effluent disposal area, four percolation test borings were completed. Two of the borings were conducted on the west side of the proposed disposal area and two borings were completed on the east side. Each side had a shallow(24"/25" depth)boring and the other two borings were completed at the deeper depths (36"/42") depths. Test locations are depicted on the Google Earth Aerial photo. SSS§ 6.3. After drilling, the sidewalls of the four borings were scored with a pry-bar to open potentially smeared soil surfaces and the cuttings removed. Two inches of pea gravel was placed at the bottom and a three-inch perforated PVC pipe was inserted in each test boring to prevent cave-ins. After these procedures, the borings were pre-saturated with 12 inches of water approximately 24 hrs prior to the start of testing. SSS§ 6.4, 6.5. On August 5, 2021, percolation testing commenced for the two west perc test borings. The two east perc tests were conducted on August 13, 2021. No standing water was observed in any of the four test borings after the 24-hr soak period. Consequently, EHD Perc Test Procedure #2 was conducted. Testing was done over a four-hour period to induce maximum soil saturation. A summary of the perc test results with corresponding application rates in gallons of effluent accepted per square foot of soil per day are illustrated below: TABLE 2 r r✓/iv-: ,/`z„ir%/�/��✓i;,i�-riir//�////.,//.,�,,r/im%i'i�/rri:. d,ayWEST 25” PERC TEST 35.7 min/inch / 0.467 gallons/f2/ WEST 36" PERC TEST 14.7 min/inch / 0.729 gallons/ft2/day EAST 24" PERC TEST 250.0 min/inch / 0.100 gallons/ft2/day EAST 42" PERC TEST 10.9 min/inch / 0.786 gallons/ft2/day AVERAGE APPLICATION RATE OF DEEP TESTS=0.758 gallons/ftz/day Application Rates adapted from Waste Quality Controlfor Siting,Design,Operation and Maintenance of On-site Wastewater Treatment Systems,based on the Perc Rate. D. GROUNDWATER INFORMATION NLS§2.1, SSS§ 4.1. Groundwater depths and elevations throughout San Joaquin County are illustrated on maps published by the County Flood Control and Water Conservation District. The 1993 Lines of Equal Depth Map indicate the depth to the water table was approximately 35 ft. The 1999 Lines of Equal Depth Map illustrates the water table to be approximately 40 ft. These two years are regarded as the highest (shallowest) depths to groundwater on record. The Spring 2018 Lines of Equal Depth Map illustrate an approximate 53 ft depth to the water table revealing a significant drop in water table elevation due to excessive pumping and limited recharge during serious drought periods. Consequently, sufficient distance exists between the soil-effluent interface and the highest anticipated depth to groundwater. From the Spring 2018 Lines of Equal Elevation Maps, groundwater directional flow is in a north-northwesterly direction. Page -4- Chesney Consulting