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January 27, 2005 NOA Project Number: E04070B I Page 7 I Potential for Degtadation FChesney Consulting identified 30 total feet of silty clay to clayey silt, 10 total feet of silt, and 5 total feet of silty sand within a 45-foot exploratory soil boring,with horizontal layering of soils which tends to decrease infiltration. Below the 45-foot soil boring, there are an additional 60 feet of soil to R groundwater. It appears from-these conditions that only minimum vertical infiltration of water should be possible. F1Measured increases in freeboard during periods of good data were on an order of magnitude that suggests evaporation may be responsible for the majority of water loss in the storage pond. In their 2001 Nitrate Laadin,g Study Soil Suitability Study,Valley Ag Research included a hydraulic conductivity test intended to determine the rate of groundwater infiltration near the storage pond. According to that report, "the test results show the hydraulic conductivity of the subsoil silt strata possess a comparatively slow permeability and suggest it would theoretically take a water molecule approximately 9,141 days or 25 years to travel from near the soil surface to the water table, —95 ft below grade." Specific limitations on nitrogen,BOD,and pH in the wastewater are provided-by the WDRs.only as they relate to land application of the wastewater. ,In the absence of specific guidance, the recommended maximum drinking water concentrations from several regulatory sources have-been utilized. The average concentrations in the wastewater at Morada Produce for this period meet or exceed the recommended drinking water concentrations for nitrate as nitrogen,TDS,residual chlorine, and TTHMs. The pH in the storage pond water was found to exceed the recommended drinking water range on 15 occasions out of 37 total events. These high pH values were recorded during a time period when no influent was discharged to the pond and no effluent was pumped from the pond and may result from a natural algal bloom on the storage pond. The wastewater was not applied to land at any point during the monitoring period. Chloroform has been detected in the storage pond water at concentrations below the drinking water standards but exceeding the human toxicity value. It is the intention of Morada Produce to eliminate chloroform from its wastewater in 2005 by treatment that will neutralize free chlorine before it is released to the wastewater storage pond. The addition of the extensive metering systems referenced in the Technical Repw--Meter INstallation ,in addition to this treatment system, should greatly reduce the potential for degradation to groundwater. F1 $Neil O.Anderson&Associates,Inc.,Technical Report—Meter Installation,January 13,2005. E "0104 1 :