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rFBase IELD BASED N EHD SEWAGE STANDARDS LD EXAMPLE: apacity= 1,200 gallons apacity (BTC)+ Average Daily Flow(ADF) x Soil Factor(SF) _ 1,200 gal BTC+(4 people x 30 gallons= 120 gpd ADF)= 1,320 x 0.200 SF(Based on perc test results)-- 264 esults264 lineal ft of leachline(LFLL) 264 LFLL x 60%= 158 LFLL =2 - 80 feet long leachlines 264 - 158 = 106 feet remaining. Equivalent to two - 33 inch diameter seepage pits (120 LFLL) Therefore, septic system to consist of one - 1,200 gallon septic tank, 2 - 80 foot long leachlines, and two - 33 inch diameter seepage pits, 25 feet deep. IV. CONCLUSIONS AND RECOMMENDATIONS FOR NITRATE IMPACT MITIGATION The document supplied by Mr. Ceci indicates that there is very minor use by customers of his Fremont Facility and in all likelihood, would be representative of what will occur at this new Tracy facility. From the well water data collected,there is what can be considered, elevated levels of nitrate within the groundwater underlying the subject property, since this nitrate concentration is over one-half the Maximum Contaminant Level (MCL). The Hantzsche/Finnemore Formula predicts a resultant average concentration in the recharge water from the proposed project to be 5.3 ppm as NO3. Based upon this formula, which is in our opinion the closest nitrate loading projection to reality,the nitrate impact from the proposed development is one-fifth the nitrate concentration currently in the underlying groundwater(25 ppm NO3). This may theoretically cause a"dilution effect" to the water table nitrate concentration. It may be theorized that the nitrate concentrations in the underlying groundwater are in equilibrium and if all factors affecting this concentration remain steady, there may not be a significant increase in nitrate. It has been observed by the Environmental Health Department over the years that nitrate concentrations can fluctuate substantially at different times of the year. This is due to factors such as irrigation recharge, rainfall weather patterns and well water usage. For the new well to be installed, the water should be tested for compliance with Environmental Health Department regulations. Nitrate concentrations should be compared with those observed from the well at the Cement Company. The Environmental Health Department will require a 200-foot grout seal on the new well. The percolation test results indicate the typical leachline depth soils of approximately 42 inches below grade have a porosity that allows for excellent percolation. Seepage pits are warranted and will be required by the San Joaquin County Environmental Health Department to ensure proper management the septic effluent. Since the groundwater is deep in this locale,pits or sumps can be installed with the assurance of sufficient biological treatment of the effluent before the groundwater is encountered. of . Page -8- Chesmy Consulting