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Ground Water Impacts <br /> The ground water point of compliance well (GWPOC),monitors well DCAL02 screened in Dry Creek alluvium <br /> and located north of the permit boundary. Standards for this well were established in 2009 through Technical <br /> Revision TR63. For the years 2015 through 2019 water quality at DCAL02 has consistently met water quality <br /> standards with the exception of dissolved iron. The iron standard was established at 8.06 mg/L. Samples <br /> collected over the previous five years indicate no statistically significant change in the dissolved iron <br /> concentrations when compared to the baseline range(6.96— 11.lmg/L,a mean of 8.59 mg/L), established in <br /> 1998. As dissolved iron comprises the only ground water quality exceedances,this suggests that Dry Creeks' <br /> alluvium ambient iron concentrations are above the standard,and the elevated iron is not indicative of an offsite <br /> impact to the groundwater system. DRMS finds that the groundwater iron measured falls within the range <br /> established with baseline data. <br /> Surface Water <br /> Instream numeric standards for Dry Creek reference the Colorado Water Quality Control Commission's <br /> (CWQCC),Yampa River Segment 13d for upper Dry Creek and Yampa River Segment 13e for Sage Creek. <br /> For the upper Dry Creek segment total recoverable iron excursions have occurred numerous times at points <br /> WSH7 and WSHF1 over the last five years exceedances of pre mine conditions occurred once. Monitoring at <br /> outfalls 016 and 017 upstream of points WSH7 and WSHF 1,was significantly less than the standard. It appears <br /> that the elevated iron is unrelated to runoff from the mine site. No other water quality excursions have occurred <br /> between 2015 and 2019 in the upper Dry Creek Segment. <br /> Spoil Springs <br /> Five spoil springs are monitored at the site and results are compared to the CWQCC Agricultural Use surface <br /> water standard CDPHE Regulation 31. No Agricultural Use standards(manganese),were exceeded at any of the <br /> spoil springs. <br /> For Sage Creek Segment 13e no water quality excursion occurred during the past five years. <br /> Permit requirement of the Colorado Department of Public Health and Environment(CDPHE), set monitoring <br /> protocol for the NPDES outfalls at the site. Six outfalls are located within the SL7 Phase III bond request. Over <br /> the past five years(2015 through 2019),total recoverable iron was exceeded once in 2016,coinciding with a <br /> runoff event. Exceedances in the period from February through May fall under the temporary modifications that <br /> allow for excursions of iron during spring runoff events. No other exceedances of NPDES limits occurred <br /> during this time period. <br /> Protection of the Hydrologic Balance <br /> All ponds and stock tanks have been approved by the Division of Water Resources to remain as permanent <br /> structures. Permanent pond demonstrations have been made for Ponds 006, 016 and 017 and reclamation in <br /> their watersheds has not yet been released. <br /> Replaced plant medium and topsoil should exhibit infiltration rates exceeding that of premining soils,thus <br /> reducing sheet flow and associated erosion and sediment transport. <br /> Permit Number: C1982057 Page 14 of 15 <br /> Phase III <br />