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-7 <br /> VALLEY -AG'z <br /> I9F. SUAltU11 _ <br /> November 26, 2001 <br /> V.A.R.# 56.01 <br /> FOR: Mr. Cliff Goehring <br /> % Mr. Ron Heinzen, R.C.E., R.G.E. <br /> Kleinfelder, Inc. <br /> 2825 East Myrtle Street <br /> Stockton, CA 95205 <br /> PROJECT: Additions to Mokelumne River School <br /> SA- 99-86 <br /> 18950 North Highway 99 <br /> Lodi, CA <br /> SUBJECT: New Septic System Addition - Environmental Investigation and Design Example <br /> INTRODUCTION <br /> Valley Ag Research has provided the San Joaquin County Environmental Health Department <br /> (PHS-EHD) with information, data, research and reporting on agricultural and environmental <br /> health issues for the past decade. Since nitrate impact originating from agricultural fertilizer <br /> inputs is interrelated with septic system impact, we have conducted several studies to further <br /> advance the knowledge of nitrate generation from these two sources. <br /> In response to the request of Mr. Ron Heinzen of Kleinfelder, Inc., we are providing additional <br /> information and a design example to complete the requirements for PHS-EHD. The design <br /> example pertains to the physical appurtenances of the new septic system to serve the new <br /> classroom building addition, and not the actual orientation of the disposal field. <br /> ENVIRONMENTAL INFORMATION <br /> To quantify nitrate impact from the eastern leachfield (See Site Plan), a hand-boring was drilled <br /> to retrieve soil samples at the approximate midpoint of the leachline, adjacent to the trench. The <br /> midpoint was selected since it was assumed the biomat would be in equilibrium due to the <br /> maturity of the leachfield, thus allowing a uniform application of effluent the entire length of the <br /> leachline. This is illustrated on the attached schematic, as adapted from Metcalf and Eddy: <br /> Wastewater Engineering - Treatment Disposal, and Reuse. The boring was drilled to a depth of <br /> 12 ft, with samples taken from 1 ft, 5 ft, 8 ft and 12 ft. These depths are denoted on the attached <br /> Soil Analysis Report (e.g., LFIFT=Leachfield 1 foot depth). Several soil constituents were <br /> tested, with the nitrogen concentration as the primary constituent. Test results reveal the soil <br /> profile to possess very little nitrate-nitrogen content. The Total Kjeldahl Nitrogen (TKN) and <br /> ammonium concentrations are also very low. <br /> Page I of 4 <br /> P.O. Box 3794 a Turlock,California 95381 1 (209) 668-1403 1 Fax (209) 668-2598 <br />