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Bird Road Facility Page 7 of 13 F1 Project Number: E07183A November 30, 2007 of water above the bottom level of the percolation test hole. The readings were taken evq.� minutes for a period of four hours. I.6.6 Percolation Test Forms and Results The completed percolation test form is included in th p` pendia of this report. A shallow percolation test is defined by the EHD as eing between 36 and 42 inches in depth; a satisfactory percolation rate for a shallow test is less than or equal to 60 minutes per inch drop. A deep percolation test is defined as being between 3.5 and 25 feet in depth; a satisfactory percolation rate for a deep test is 30 min/in or less. One percolation test must demonstrate a satisfactory percolation rate within the proposed septic system disposal field of each parcel to utilize a standard septic system. Details of the percolation tests are summarized in the table below. I Table 3 Summary of Percolation Tests. 1 Test No., Percolation Test Percolatio Rate Test Duration Comments Date Tested Depth (ft.) ( ' inc (see notes) 11-20-07 3.3 9.61 4 hr. Satisfactory Pert Rate Note: A satisfactory percolation rate for a"shallo "test is less than equal to 60 minutes per inch. A satisfactory percolation rate for a"deep"t is less or equal to 30 minutes per inch. I.6.7 Discussion of Percolation Test Results E The soils within the sewage disposal areas of the site have demonstrated satila,� percolation rate in accordance with the requirements of the EHD for the use s septic system. 1.6.8 Discussion of Septic System Sizing Septic system construction should follow the San Joaquin County On-Site Wastewater Disposal F1Standards where applicable. II. NITRATE LOADING STUDY Because of concern regarding nitrate leaching into ground water from septic systems, a nitrate F11 loading analysis was required by the EHD for the proposed development to measure the potential concentration of percolating effluent and rain fall over the long term. Where �j percolating effluent leaches into the ground, ground water quality may be impacted to some F� 11 degree should the effluent reach ground water. 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 (1992), which provides a convenient and simplified method to estimate long-term ground-water nitrate impacts on an area-wide basis. "444s 902 Industrial Way•Lodi,CA 95240•209.367.3701 •Fax 209.369.4228 t2007Neil 0.Anderson&Associates,Inc