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Surface Water <br />There are two NPDES sites at HGT, 001 and 002. NPDES 002 did not flow in <br />2007. NPDES 001 flowed for six weeks only, as a result of snowmelt in <br />March and April. An analysis of a sample collected for each event is <br />provided in Appendix B, Water Quality Reports. No NPDES effluent limits <br />were exceeded. On October 29, the leaking headgate at 001 was repaired <br />by sealing it with tar. In addition, the leaking discharge culvert at <br />that outfall was repaired with cement. <br />Surface water quality reports for 2007 are presented in Appendix B. <br />Data provided includes a water quality report for this year, a listing <br />of all historic flow data (and remarks) since October 1994, and a <br />regression plot of historic total dissolved solids (TDS) data. <br />Table 3 provides a comparison of this year's surface water quality to <br />CDPHE receiving stream standards for Dry Creek (Yampa Segment 13d, <br />Regulation No. 33, December 2005). This Paradox database generated table <br />does not include the units of concentration (mg/l or ug/1) for each <br />parameter. The units used for each parameter are the same as those <br />listed on the Surface Water Parameter List (Table 1) and are also the <br />same as those used in the water quality reports. The frequency column on <br />Table 3 indicates the number of exceedances out of the total number of <br />samples (i.e., 1/2 indicates one exceedance out of two samples). Below <br />is a summary of standards that were exceeded. <br />For upstream Site HGSD1, the only standard exceeded was sulfide <br />(standard 0.002 mg/1). On May 16, a sulfide value of 0.0027 mg/l was <br />observed. <br />For downstream Site HGSD3, standards exceeded were: <br />Sulfide: May 16 value = 0.0036 mg/l <br />Total recoverable iron (standard 1.0 mg/1): Sept. 20 value = 2.12 mg/l <br />However, no exceedances at HGSD3 were a result of an NPDES discharge <br />(ie, neither outfall was flowing at the time of the stream exceedances). <br />Therefore, the exceedances are likely a result of natural conditions. <br />2