Laserfiche WebLink
KLEINFELDER <br /> Test Number Depth, ft. Percolation Rate min./inch <br /> P-1 15 6.7 <br /> P-2 3.5 Did not ercolate <br /> P-3 3.5 250 <br /> P-4 14.75 6.6 <br /> Following our percolation testing, a staff engineer with our firm obtained a sample of <br /> groundwater using clean procedures from a well located at 30987 Highway 120, the neighboring <br /> property to the west. The well was located approximately 60 feet west and 80 feet north of that <br /> parcel's southwest corner. That same day, the water sample was submitted to Far West <br /> Laboratories using chain-of-custody procedures for DBCP and nitrate testing. The test results <br /> and a copy of the chain-of-custody are attached. <br /> NITRATE LOADING CALCULATIONS <br /> Per SJCPHS/EHD requirements, the following summarizes our nitrate loading calculations for <br /> the proposed leach fields. The drinking water standard for nitrate is 45 milligrams per liter <br /> (NO3) and 10 mg/1 as Nitrogen(N) in groundwater. In our evaluation of nitrate loading, we have <br /> used the Hantzsche mass balance equation (source: Predicting Ground-Water Nitrate-Nitrogen <br /> Impacts, Hantzsche and Finnemore (1992)), which is presented below with an explanation for <br /> each factor and the value used in our study. The selection of parameters was based on previous <br /> studies and investigations performed by our firm and others, San Joaquin County Sewage <br /> Standards, and information provided in a report dated March 19, 1997 prepared by the Questa <br /> Engineering Corporation and authored by Mr. Hantzsche for a development in the Stockton area. <br /> Ne=AWNw0-D) + r <br /> AW+r <br /> Where: <br /> Ne = Average calculated nitrate-nitrogen in groundwater resulting from domestic sources <br /> and precipitation—mg/1, as N <br /> A = Number of dwelling units per acre on septic tanks (unit/acre) = 1.93 (estimated by <br /> converting the maximum/peak water usage at the site on a game day to an <br /> equivalent number of dwelling units by dividing the estimated water usage by the <br /> typical water usage for a 3 bedroom home (150 gal./day). This value is then divided <br /> by the total acreage of the project site (18.3 acres). A summary of our calculation is <br /> a follows: <br /> Water Usase <br /> Residential Homes - 2 @ 150 gal./day per(300 gal./day total) <br /> Clubhouse—40 players/coaches @ 25 gal./day per(1,000 gal./day total) <br /> Spectators—400 @ 10 gal./day per(4,000 gal./day total) <br /> A= (300+1,000+4,000)/150 gal. per day/18.3 acres= 1.93 <br /> 20-4685-O1.G01/2002R367 April 18,2002 <br /> ©2002 K:leinfelder,Inc. Page 3 of 5 <br /> • <br />