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f1 � FCGroundwater directional flow is normally assumed to be in the direction of land surface declination. would make directional flow in a northeasterly direction. However, it is known that there aregwell pumps at the adjacent gravel quarry plant which may influence groundwater directional flow. These pumps may pull groundwater under the property from a northeast direction to a northerly/westerly direction. A water sample was obtained from the on-site domestic well (location illustrated on the Site Plan in Appendix 1). The water sample was taken from a sample port on the discharge pipe. Two separate containers were used for the analyses. A plastic bottle was used for the standard Water Analysis Report sample and the Irrigation Water Analysis Report sample. The sample bottle did not contain preservative. A sterilized bottle was used for purity analysis, with test results revealing absent Total Coliform. The samples were drawn after the well pump had run for three cycles to ensure aquifer formation water was sampled. The samples were placed in a cooled ice chest and transported to A&L Labs of Modesto, under the attached Chain of Custody. Testing of the well water sample reveals a nitrate concentration of 18 ppm (4 ppm NO3-N). The Maximum Contaminant Level (MCL) for nitrate (as NO3) is 45 ppm. Dibromochloropropane and (DBCP) and Ethylene dibromide (EDB) were not tested, per EHD staff. The nitrate-nitrogen loading calculations below are contingent upon the environmental factors required for nitrification to occur. These conditions include soil pore-space oxygen content, soil temperature, pH, electrical conductivity, organic matter, cation exchange capacity, and alkalinity. Alkalinity in wastewater effluent is derived from the domestic water supply and the introduction of wastes to the wastewater. Nitrification consumes approximately 7.1 mg of alkalinity for every milligram of ammonia-nitrogen(NH4-N) oxidized. Assuming complete nitrification of a Total Nitrogen(TN) concentration of 53 mg/L, as determined in Section III D below, and considering that ammonium typically composes 70-90% of the total nitrogen in septic tank effluent, we find that: 53 mg N/L x 80% =42 mg NH4 NIL x 7.1 mg CaCO3 = 301 mg/L alkalinity required. Given that the water sample tested has a comparatively high bicarbonate concentration at 293 ppm, which leads to bicarbonate alkalinity, sufficient alkalinity exists in the water for nitrification to occur. B. SURFACE WATER INFORMATION Surface water consists of all other water sources originating on the surface of the project, other than septic system effluent. These sources include rainfall, surface runoff, domestic irrigation and on-site stormwater retention for each of the proposed residential units. The attached San Joaquin County of Public Works - Isohyetal Map indicates 8 inches of rainfall to be the Mean Annual Precipitation in the area of the project. There should be no impact to surface waters from septic effluent provided applicable distance requirements as promulgated in the County Sewage Standards are followed. This particularly applies to the Delta-Mendota Canal, which is concrete-lined. Hospital Creek is approximately 0.2 miles south of the property. Influences, such as flooding to the subject property from this Creek are unknown at this time. 7 Chesney Consulting