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KLEINFELDER Test Number Perfcrmed' Depth-(feet) Percolation iRafe( ' /inch) P-1 23.0 25.9 P-2 10.0 41.6 P-3 3.0 83.3 �F 7. NITRATE LOADING CALCULATIONS Per SJCEHD requirements, the following summarizes our nitrate loading calculations for the proposed leach field. The state drinking water standard for nitrate is 45 Fi milligrams per liter (NO3) and 10 mgll as Nitrogen (N) in groundwater. In our evaluation of nitrate loading, we have used the Hantzsche mass balance equation (source: Predicting Groundwater Nitrate-Nitrogen Impacts, Hantzsche and Finnemore 3 (1992), equation (1) pg. 491, which is presented below. . N, = INw (1-D) + (Nb) R I + R The selection Fi of parameters used in the equation was based on previous studies and investigations performed by our firm and others, previous communication with Mr. Mike Huggins with SJCEHD gg and information o mation provided in a report dated March 19, prepared� 1997 r e b p p y the Questa Engineering Corporation a 9 g and authored b p y Mr. Hantzsche k for a development in the Stockton area. The Hantzsche mass balance equation is a simplified prediction of the nitrate impacts of on-site sewage disposal systems over a defined geographical area. In order to evaluate "1," the volume rate of wastewater entering the soil averaged over the gross developed area, assumptions had to be made regarding the use of facilities at the new ministry center. As previously stated, there would be no bathing, laundry, dishes, etc., at the new facility. With the proposed meetings relatively short, between 1 and 2 hours, even if a quarter of the attendees used the restroom facilities and used 3 gallons per visit, this would still amount to only 787 gallons per week. We have assumed that the 5 full-time office employees would contribute 5 gallons per day for a F1 total weekly amount of 175 gallons. The combined total is 787 + 175 = 962 gallons/week. The subject property will also receive flow from the new restroom additions on the adjacent property. As described earlier, an estimated 1,225 people F1 might use the adjacent church facilities each week for approximately 1 to 2 hours. Assuming a quarter of these people might use the restroom facilities, the approximate additional flow using the same 3 gallons per visit criteria would be 919 gallons per P week. The total flow into the new disposal system is therefore expected to be approximately 1,881 gallons/week. The property encompasses a total of approximately 4.91 acres. We have not considered any of the church property west of the disposal site in our calculations, although with the transfer of flow from the main church building, this western portion of property is under utilized. Therefore, as noted above, 56915.G01/ST05R823 August 30,2005 O 2005 Kleinfelder, Inc. Page 5 of 8 1•