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COLORADO DEPARTMENT~F HEALTH, Water Qua7.ity Contro~Division <br />Permit Number CO-0032751 Page 2 . <br />RECEIVING WATERS: Approximately 200 feet northwest of Cross Mine is the <br />(Continued) Caribou Mine, which contributes a portion of flow to <br />Coon Track Creek upstream of the Cross Hine discharge. <br />For effluent quality from the Caribou Mine, refer to <br />the Caribou Mine, CDPS permit No. CO-0037923. The <br />Caribou Mine discharge quality is also summarized in <br />Appendix D. <br />SUB-BASIN, SEGMENT: Segment 3, Boulder Creek Sub-basin, South Platte River <br />Basin <br />CLASSIFICATION: Recreational, Class 2 <br />Aquatic Life, Class 1 (Cold) <br />Water Supply <br />Agricultural Use <br />(See Appendix A for receiving waters WQS) <br />STREAM LOW FLOW: The flows which are used to calculate acute and chronic <br />effluent limitations are the one day in three year <br />acute low flow (1f:3) and the 30 day in three year <br />chronic low flow (30E3). These seasonal flows have <br />been determined for Coon Track Creek above the Caribou <br />Mine by the Water Quality Control Division, and are <br />described in the i.'ollowing chart summary. <br />Month lE3 (Acute) 30E3 (Chronic) <br />January 0.041 cfs (0.026 MGD) 0.062 cfs (0.040 MGD) <br />February 0.041 cfs (0.026 MGD) 0.062 cfs (0.040 MGD) <br />March 0.073 cfs (0.047 MGD) 0.062 cfs (0.040 MGD) <br />April 0.11 cfs (0.071 MGD) 0.084 cfs (0.054 MGD) <br />May 0.33 cfs (0.21 MGD) 0.20 cfs (0.13 MGD) <br />June 1.8 cfs (1.2 MGD) 0.91 cfs (0.59 MGD) <br />July 0.60 c.fs (0.39 MGD) 0.46 cfs (0.30 MGD) <br />August 0.29 cfs (0.19 MGD) 0.25 cfs (0.16 HGD) <br />September 0.18 cfs (0.12 MGD) 0.16 cfs (0.10 MGD) <br />October 0.13 cfs (0.084 MGD) 0.15 cfs (0.097 MGD) <br />November 0.10 cfs (0.065 MGD) 0.087 cfs (0.056 MGD) <br />December 0.058 cfs (0.037 MGD) 0.062 cfs (0.040 MGD) <br />FACILITY FLOWS: Maximum design flaws for the Cross Mine: <br />0.036 MGD (or 25 gpm) for August through March <br />0.122 MGD (or 85 gpm) for April through June <br />0.093 MGD (or 64.5 gpm) for July <br />Facility flows used for WQS mass balance equation <br />calculations, as described later in pages 6 and 7 of <br />this rationale, axe based upon the discharge flows from <br />both the Cro:as Mine and the Caribou Mine. For monthly <br />reported discharge flows for the Cross Mine, see <br />Appendix B1. For further details regarding the Caribou <br />Mine discharge flows, see Appendix D. <br />