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KLEINFELDER " 6. PERCOLATION TESTING The 6-inch diameter percolation holes were drilled with the same equipment as the soil profile borings. Eight percolation holes, two on each of the proposed parcels, were drilled on the subject property. The holes had scored sides and no significant loose material in the bottom of ` the hole. The holes on proposed Parcels 1 and 2 were drilled and prepared before 7:15 am on October 20, 2003 in accordance with SJCEHD criteria. The holes on proposed Parcels 3 and 4 were drilled and prepared before 9:30 am on the same day, also in accordance with SJCEHD criteria. The preparation procedure calls for first placing about 2 inches of fine gravel at the bottom of the borehole. The hole is then pre-soaked with a minimum of 12 inches of water at least 24 hours prior to performing the test. The percolation tests were started at 7:25 am for r. proposed Parcels 1 and 2 and 12:05 pm for proposed Parcels 3 and 4 under sunny and warm weather on October 21, 2003, in accordance with accepted guidelines using clear potable water. The approximate depth of each percolation test below existing site grade is shown on the following table. All holes exhibited some slogghing or caving after presoaking as noted in the table below (performed depth vs. installed depth). Based on the sandy materials encountered during drilling at this site, some caving is not unexpected. The holes were dry prior to tectLng 6. From a fixed reference point, a marked location on the side of PVC pipe inserted into the hole, the drop in water level is measured in approximately 30-minute intervals for four hours, refilling as necessary to maintain the prescribed amount of water over the gravel (SJCEHD Procedure #2). Under the observation of a representative from the SJCEHD, the last 30-minute reading of the four-hour period is recorded and used to calculate the percolation rate in minutes per inch. The estimated percolation rates are summarized below. A copy of our field percolation test results signed by a representative from SJCEHD is attached. Details of each test can be found on the respective percolation test sheet. Test Number Performed Depth Installed Depth Percolation Rate feet feet min./inch P-1 2.6 3.3 S- 9.3 10 8 P-2 2.9 3.3 13 . 5.1 7 42 S< P-3 3 3.3 6 ,- 3.3 5 5 P-4 3 3.3 10 8.8 10 4 L 7. NITRATE LOADING CALCULATIONS L Per SJCEHD requirements, the following summarizes our nitrate loading calculations for the proposed leach fields. The state drinking water standard for nitrate is 45 milligrams per liter L (NO3) and 10 mg/l as Nitrogen (1) in groundwater. In our evaluation of nitrate loading, we L, 37050.G01/ST03R1750 November20,2003 ©2003 Mcinfelder,Inc. Page 4 of 6 L