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Hughes Hardwoods 1.0 May 5,2003 Page 5 V' The percolation test borings were pre-soaked on May 1, 2003 according to the method prescribed by the EHD. One May 2, 2003, a 4-hour test was conducted for both tests in accordance with the requirements of the San Joaquin Division of Environmental Health Department and was observed by Mike Escotto of their office. The following table summaries the test results: Table 4. Summary of the Percolation Test. Name, Location Depth of test Length Result Comments Date Tested P-1 shallow, Proposed septic 3 feet 4 hours None Test failed to achieve the minimum 5/2/03 field percolation rate of<=60 min/inch for a"shallow"percolation test. bw P-1 deep, Proposed septic 25 feet 4 hours 15 Test achieved a satisfactory 5/2/03 field min/in percolation rate of<=30 min/in for a "deepercolation test. According the EHD, a septic system disposal field is acceptable if either the"shallow"or"deep" d1,2 percolation test has achieved a satisfactory percolation rate. Since the 25 foot deep boring achieved a satisfactory percolation rate and EHD allows seepage pits in this area, the septic system disposal field was found to be acceptable for use with shallow leach lines and seepage P:V pits according the Sewage Standards publication of the EHD of San Joaquin County. 6.0 NITRATE LOADING STUDY Because of the concern of nitrate leaching into ground water from septic systems, a nitrate loading analysis was required by the EHD for the proposed facility to measure the potential concentration of percolating effluent and rain fall over the long term. If the proposed development is disposing of septic effluent to land, ground water quality may be impacted to some degree. The method utilized for the nitrate loading analysis is based on a simple mass balance formula, _ discussed in a published article by Hantzsche and Finnemore,3 which provides a convenient and simplified method to estimate long-term ground-water nitrate impacts on an area-wide basis. Hantzsche and Finnemore found that over a long period of time, water quality in the upper saturated ground-water zone closely approximates the quality of percolating recharge waters. They believe that their method is a good planning tool and provides useful information to 3 Hantzshe N.N.,Finnemore,E.J. 1991,Predicating Ground-Water Nitrate-Nitrogen Impacts. Ground '.. Water,Vol.30,No.4. ?pERtO o � �ttoc•