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I Black Oak Estates, Shallow Percolation Addendum Page 2 diameter perforated pipe was then placed in each hole and backfilled with gravel. The test holes were filled with water 24 hours prior to running the tests. The last half hours of the test readings were witnessed by a county health official and the test data obtained is enclosed in Appendix A, Shallow Percolation Test Data. The percolation rates have been adjusted to account for the gravel and pipe backfill. Calculations for this adjustment are on the test data sheets. The results of the shallow percolation tests are summarized in Table 1, Percolation Test Results Summary Addendum. As indicated,the surface clay soil has poor percolation characteristics and the shallow percolation tests performed were performed in small stratums of sands as indicated. Passing shallow percolation tests were obtained on each of the proposed lots. According to San Joaquin County criteria, a failed test is one in which the percolation rate exceeds 120 minutes per inch. Generally, the passing shallow tests for lots 1 through 45 were located in the front to middle of the lots and lots 46 through 57 were located in the middle to rear third of the lots. Due to the limited thickness and inconsistency of the sand strata encountered at the subject site, it is our opinion that future septic systems be designed utilizing shallow leach lines with pits located at the end and in accordance to San Joaquin County Criteria. TABLE 1, Percolation Test Results Summary Addendum Suin.mary . CgutE Adjusted Percolation Rate Adjusted Percolation Rate Lot# (Minutes/Inch) Lot# (Minutes/Inch) ........................ ....................... .............I.......... ....................... ........................ <1>< 15.6 30 103.2 20.0 8.6 ><'«': 3 38.4 8.6 8.6 33 64.5 5 8.9 31 8.6 7 86.0 36 32.3 8 35.5 37 32.3 au A.