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Schwartzwalder Mine -Hydrologic Evaluation of Mine Closure and Reclamation 92 <br />7.1 Groundwater Quality Standards and Point of Compliance <br />CPDHE has developed numeric standards that apply to classified groundwater. The majority of the <br />numeric standards are the maximum contaminant levels (MCLs) for public drinking water supplies, as <br />established by the National Primary Drinking Water Regulations. The remainder are derived from the <br />Colorado Basic Water Standards for Ground Water (SCCR 2002-41, amended November 8, 2004, effective <br />March 22, 2005). These human health levels are set to protect the public from acute poisoning and from <br />long-term "chronic" effects. The numeric standards listed in column 1 of Table 28 are applicable to <br />groundwater classified "Domestic Use-Quality". <br />The classification system consists of five (5) categories or classes based on existing and potential future <br />uses and actual water quality data. Groundwater may be assigned more than one class because it may have <br />more than one existing or potential use. The classes are: <br />1. Domestic Use -Quality <br />2. Agricultural Use -Quality <br />3. Surface Water Quality Protection <br />4. Potentially Usable Quality <br />5. Limited Use and Quality <br />The point of compliance was set by DBMS and was accepted by the Water Quality Control Commission <br />(WQCC). These organizations typically recognize that mining activities occur within groundwater bodies <br />and that water quality within the disturbed area will obviously change. Points of compliance are <br />established outside the disturbance area to protect the water body while allowing the mining activity. <br />A point of compliance well was originally drilled at the property boundary for the alluvial groundwater. <br />However, downgradient well MW8 is always dry and has never been sampled. The alluvium pinches out, <br />and groundwater in the alluvium is forced into Ralston Creek. The creek is essentially the point of <br />compliance for groundwater in the alluvium, and is monitored routinely at station SW-BPL (below the <br />property line). <br />4109B.071116 Whetstone Associates • <br />