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Table A -5a <br />Low Flows for East Paradox Creek and Bull Canyon at the JD -7 and JD -9 Mines' <br />WWTF <br />Low Flow <br />(cfs) <br />Annual <br />Jan <br />Feb <br />Mar <br />Apr <br />May <br />Jun <br />Jul <br />Aug <br />Sep <br />Oct <br />Nov <br />Dec <br />1E3 <br />Acute <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />7E3 <br />Chronic <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />30E3 <br />Chronic <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />0.00 <br />Cotter Corporation Water Quality Assessment C00036251 <br />IV. Receiving Stream Information <br />Low Flow Analysis <br />The Colorado Regulations specify the use of low flow conditions when establishing water quality based <br />effluent limitations, specifically the acute and chronic low flows. The acute low flow, referred to as 1 E3, <br />represents the one -day low flow recurring in a three -year interval, and is used in developing limitations <br />based on an acute standard. The 7 -day average low flow, 7E3, represents the seven -day average low <br />flow recurring in a 3 year interval, and is used in developing limitations based on a Maximum Weekly <br />Average Temperature standard (MWAT). The chronic low flow, 30E3, represents the 30 -day average <br />low flow recurring in a three -year interval, and is used in developing limitations based on a chronic <br />standard. <br />Stream Segment COGULDO3a -All tributaries to the Dolores River <br />Although there is periodic flow in East Paradox Creek and Bull Canyon upstream of the JD -7 and JD -9 <br />Mines' WWTF, the 1E3, 7E3 and 30E3 monthly low flows are set at zero based on information provided <br />by the local Water Commissioner. For this analysis, low flows are summarized in Table A -5a. <br />The ratio of the low flow of the East Paradox Creek to the JD -7 Mine's WWTF design flow is 0:1 <br />The ratio of the low flow of the Bull Canyon to the JD -9 Mine's WWTF design flow is 0:1 <br />Note that since the low flow has been determined to be zero, the ambient water quality discussion is <br />unnecessary and has therefore been deleted in this WQA. This is explained in more detail under the <br />Technical Information discussion in Section VI. <br />Appendix A (WQA V 7.0) <br />Page 12 of 23 Last Revised 06/10/10 /AO <br />