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L 1 UEC Document No.: R3579901 February 8, 1999 Soil Percolation test hole #3 maintained good integrity throughout the 4 hour time period of the soil percolation test. During the test, drops in water level ranged from 3.75" in a 30 minute interval to 0.5" in a 30 minute interval. The 0.5' drop in water level was observed during the final test interval; the following calculated percolation rates are based upon the final test period. The resultant calculated soil percolation rates for hole#3 are .0167 inches of water per minute or 59.9 minutes per inch of water. Consequently, the area located immediately north of the Calva Products structure and west of the existing septic system percolates adequately. The significance of Soil Percolation Hole #3 is that the soil conditions were observed to be identical to those observed in Percolation Test Hole #4. Although UEC is NOT proposing to use the area south of the drainage pond as a 100% septic system replacement area, the percolation test results from Hole #3 support the conclusion that the results obtained from Percolation Test Hole #4 are in fact artificially low and should be considered as such. 3.0 NITRATE LOADING ANALYSIS An analytical assessment of the potential impact to groundwater from nitrates contained within the septic system waste water has been performed by the UEC staff; the basis of the assessment is the research work performed by Norman N. Hantzche of the Questa Engineering Corporation and E. John Finnemore of the Department of Civil Engineering at Santa Clara University. Soil samples have been collected from north of the drainage pond and analyzed for chemical content; the analytical results may be found in Appendix E. The assumptions made and the numerical values used in performing our calculations are meant to be representative of the current site and septic system usage conditions. 3.1 Site Hydrogeology According to the SJC Flood Control and Water Conservation District "Lines of Equal Depth To Groundwater" map dated Spring 1997, the approximate depth to groundwater beneath the site is 50 feet; heavy rainfall between the Spring of 1997 and the Spring of 1998 may be expected to have raised the groundwater level no more than 10%, or to a depth of 45 feet below grade. This deduction is based upon a review of historical groundwater data for the subject site area by SJC Flood Control District employee Mr. Michael Callahan. The groundwater flow direction tends to be to the east-northeast in the immediate vicinity of the subject site. 4