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October 12,2fl00 <br /> Job Number'LG00-312 <br /> Page.12 . <br /> adequate.drainage,for a conventional residential septic.system utilizing]each lines and seepage <br /> pits. The septic permit.review has shown that conventional septic.systems with seepage pits are <br /> . used in`the area. The depth to ground,water.is,.fa rl d about 76 t o 80 <br /> y .veep, o feet and the nitrate <br /> level measured-in the well appears to indicate the_water is probably at or.near"natural. <br /> -concentration levels".with respect to nitrates. No DBCP was found-in the groundwater. <br /> "M aquifer appears'to be quite bete_rogeneous-with many sand/clay layers ranging <br /> between 1 and 40 feet thick located within the unsaturated and saturated zones. .This <br /> - <br /> heterogeneity was observed in our shallow dri ' • <br /> g tY llmng to a maximum depth of 2S feet. The aquifer ' I <br /> confinement is unknbwn however it�appears'that no nitrate impacts froin local dairy,operations i <br /> agriculture,cattle.grazing,or septic systems are observable within the aquifer at the inlet depth <br /> and location of water well. Based on this information, it is possible that there is a real, apparent, <br /> or functional mow permeable zone(s).located between the surface and.ground water. <br /> If septic.systems are to'be utilized, a discontinuous and heterogeneous zone consisting of <br /> many clay layers and fairly deep ground water is more preferable then say Manteca conditions <br /> consisting of clean sand and shallow ground water. Based on the information available,.the soil i <br /> and hydrogeologic conditions appear to be favorable for the proposed developmexrt. The clad <br /> {r <br /> layers will- robably ii�ih_zbit_ the downwar -percolation of the treated se tic eluent and rain fall: �� _ <br /> The benefit of evapotranspiration could be expected in the shallow septic field that will remove . c4t <br /> moisture and consume nitrogen.' <br /> The nitrate loading analysis suggests that'the area can sustain the long term use of-3-and 4 j <br /> bedroom homes. The minimum.acreage to support the nitrate load from a three(3)bedroom <br /> home(three occupants) septic system is-about 0.75acre.. The minimum acreage to safely support <br /> the nitrate load from a four(4)(bedroom home(four occupants)_septic system is about'1.fi acre. <br /> Keep in mind that over the life of a home and family,.the-home will probably not be completely' <br /> occupied. This fact adds an additional factor of safety. <br /> Regarding par 16118�20,W22,theAitrate-loadiiig analysis has iiidicaxed that the <br /> r.. .. 'use are too small mn smze(a3lowth)towing potential high density.grosafely�pport the use of a ' <br /> . conventional septic system. futu <br /> If at some time in the re the lots were mncreased mn smze to 0x75 ' <br /> acres or,larger and satisfactory percolation rates were achieved,these e <br /> lots would be-suitabl .far <br /> similar residential level pmn�ent: <br /> Based,on the results ofthis'study, parcels,1-15, 17,19 and 21,are suitable for use with a <br /> conventional septic system. The.nitrate'analysis has shown that based on the different sizes of the, <br /> proposed.parcels, parcel numbers 1 through 14 exceed the minimum acreage requirement for a 4- ' <br />