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4. WELL BORING GEOLOGIC LOG AND ELECTRIC WELL LOG DATA The Well Completion Report (Appendix 7) illustrates the encountered lithology during the drilling of the yet-to-be-completed domestic well. It will be the requirement of EHD to have a 200-ft grout seal installed during well construction. Potential water bearing strata(perched strata) have been denoted in orange within this 20041 depth. Water in these formations should not theoretically enter the underlying aquifers. Aquifers below this grout seal have been indicated in blue. By adding the thicknesses of potential.water bearing strata below the grout seal,we find a total thickness of 151 ft, with the thickest aquifers occurring at 335 ft to 354 ft, 359 ft to 445 ft (essentially 110 ft) and 486 ft to 491 ft and 500 f'to 520 ft(essentially 34 ft). Considering the depths of aquifers, and the slow permeability strata above these aquifers, nitrate impact to these underlying aquifers should be impeded to an appreciable extent. This is highly dependent upon "leaky" aquifers that may exist above the aquifers to be drawn from, and the integrity of the grout seal to be installed at the end of well completion. Given the nature of nitrate formation originating from septic systems and agricultural production areas, which are substantial in the Clements area, it is presumed that nitrate has infiltrated the highest water bearing strata, as referenced. Transformations from these depths are unknown and unpredictable. The Electric Well Log (e-log) for the well boring is found in Appendix 7. This e-log will be used by the well designers, along with the Geologic Log on the Well Drillers Report to screen the well casing at the proper depths for adequate yield and quality. 5. ANALYSES OF ON-SITE DOMESTIC WELL WATER During the drilling of the future on-site domestic well, water samples were retrieved for chemical analyses from specific depths:294 ft, 350 ft and 458 ft(Appendix 7). The main constituent of concern for this Study of course, is nitrate. At the 294-ft depth where a sandstone stratum exists, the nitrate concentration (as nitrate) was 1.4 ppm. The subsequent two depths had nitrate concentrations of<0.5 ppm. The 1.4 ppm concentration could be a naturally occurring concentration that has accumulated over eons, or it could be leakage from higher water bearing strata during the drilling procedures. Whatever the source, it appears nitrate has not percolated and infiltrated the aquifers that will be drawn by the new well. Chloride concentrations were also tested from the respective depths. Septic systems can also contribute chloride to the groundwater. A normal human eliminates an average of 6 grams of chloride per day. Chloride travels as readily as nitrate in the vadose and phreatic zones and can be the first indicator of septic contamination. The chloride concentration in most groundwater formations averages 6 mg/L. The typical concentration of chlorides in untreated domestic wastewater is 50 mg/l, with the range being 30-100 mg/L. Therefore, the chloride concentrations of 27 ppm from 294 ft, 31 ppm from 350 ft and 13 ppm from 458 ft can be considered a potential indicator. However, chloride ions may also become trapped in the pores of sedimentary rock and chorine-bearing evaporates of shallow marine basins. It may be a possibility that chlorides are being released from the rock and gravel quarry operations near the project site. Page -10- Chesney Consulting t