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II. SOIL SUITABILITY STUDY FINDINGS The recent history (199 1) of the subject property reveals the site was an arena for horses, prior to its present use. The surrounding study area has a varied agricultural history of irrigated and non- irrigated cropland and dairies. Dairies have been recognized by the State of California as potential nitrate pollution sources. Certain crops grown on dairies such as alfalfa use, or "fix" atmospheric nitrogen for cellular synthesis which can lead to excess nitrate formation. Over application of manure or wastewater to cropland can leach nitrates into the groundwater. Nitrates can also form naturally, for example in geological formations or in atmospheric phenomena such as lightning. And of course, septic systems can contribute to nitrate contamination. There is medium density housing within the town of Banta, all with septic systems. When high nitrate levels are found in the groundwater, the sources may be diverse, as referenced above. This is probably the case with the Banta area. If conditions are favorable, a percentage of nitrogen introduced into the environment may undergo complex biological transformations with the product being nitrate molecules. When the various sources of nitrogen introduced exceed the assimilative capacity of the environment, nitrate contamination of the groundwater occurs. The static groundwater level has risen in comparison to the 1991 study when the water level was at 9.0 feet below grade. Currently, the groundwater level is approximately 7.5 feet under the proposed leachfield area. This rise in groundwater elevation can be attributed to the recent heavy rains. The on-site domestic well was analyzed for nitrate(See Appendix). The results indicate the subject well currently has a concentration of 70 mg/1 (70 ppm)of nitrate. As referenced above, the drinking water Maximum Contaminant Level (MCL) is 45 ppm. It is important that the Sant Nirankari Mission inform its Parishioners of this nitrate concentration and that pregnant women, nursing mothers, infants and young children should not drink the water from this well. The subject well should be tested for nitrate on a periodic basis,preferably every three months. The percolation rate determined by Mr. Tosch in September, 1991 was 53 minutes per inch (min/in). This test took place at the end of the summer when the soil profile was most likely dry. Our test results, performed after unprecedented rains during the month of February was 5.7 min/in. Although this appears to be a contradiction since a slower rate would be expected after heavy rains, this phenomenon has been documented before. The native clay soils under the site are considered unciform, which refers to abundant earthworm activity throughout the soil profile. 2 'Dalley Ag P pearch