Laserfiche WebLink
East Salt Creek at the McClane Canyon Mine location is in Lower Colorado River Stream <br />Segment 13a with a Numeric Standard of 20 gg/L for the selenium concentration. When <br />CDPHE Water Quality Division prepares discharge permits (NPDES), they typically evaluate <br />numerous factors (including hydrologic, physical, and biological) when setting effluent <br />limitations for constituents such as selenium. If warranted, protection of downstream segments <br />may be considered when determining the effluent limitations but that cannot be assured until the <br />permitting process is initiated (Janet Kieler, Water Quality Division - Permits. Personal <br />Communication with Edge Environmental, Inc. October 19, 2011). <br />Given the level of uncertainty that a future NPDES permit issued by CDPHE would limit the <br />concentration of selenium - discharged to Creek 4.6 gg /L, thereby not affecting the <br />selenium concentration downstream in Salt Creek and assumed critical habitat, the following <br />additional conservation measures are proposed as an addendum to the Biological Assessment: <br />"Water in the proposed sediment pond at the McClane Canyon Mine shall be monitored <br />for selenium concentration prior to discharge into East Salt Creek. If selenium <br />concentration in the pond water exceeds 4.6 gg/L, the water shall not be discharged to <br />East Salt Creek but shall be pumped from the pond and removed by tanker truck to an <br />approved disposal facility. If the selenium concentration is 4.6 gg/L or below, pond <br />water may be directly discharged into East Salt Creek in compliance with an NPDES <br />permit." <br />"The sediment pond shall be designed to handle a 25 -year storm event." <br />With these conditions, there would be no risk of increased selenium concentrations downstream <br />in Segment 13b - in East Salt Creek downstream from the Government Highline Canal and in <br />Salt Creek - due to actions by the McClane Canyon Mine. This would not be dependent of high <br />or low flow of East Salt Creek. With the restriction that the selenium concentration would be 4.6 <br />gg/L or less in any water discharged from the Mine, monitoring selenium concentrations in East <br />Salt Creek would be unnecessary. <br />Frequency of Discharge from Sediment Pond <br />The frequency of discharge from the sediment pond would be dependent upon storm events and <br />mine water discharge. During the last five years, the existing sediment pond located closer to the <br />portal area has discharged one time. It is likely that the proposed pond would discharge twice <br />per year - once in the spring with the runoff from snow melting and once in the summer during <br />the monsoon season (Tamme Bishop, JE Stover and Associates. Personal Communication with <br />Edge Environmental, Inc. October 19, 2011). <br />Location of Loma Drain <br />Loma Drain is a perennial waterbody that flows along the western edge of the proposed Fruita <br />Loadout Facility. Loma Drain joins Reed Wash approximately 0.18 mile from the Reed Wash <br />confluence with the Colorado River. Loma Drain primarily handles return irrigation flow, <br />