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Table A-10 <br />Acute Assimilative Capacities for Metals and Cyanide in Cripple Creekt <br />Parameter Upstream Effluent Combined Upstream Calculated Water Quality Notes <br /> Low Flow Flow Flow Concentration Assimilative Standard <br /> Capacity M3 <br /> QI (cfs) Qs (cfs) MI MZ <br /> Q, (cfs) <br />Mn, Dis (ug/1) 0.4 0.6 1.0 9018 --- 3677 2 <br />i, Dis (ug/1) 0.4 0.6 1.0 33.8 ]302 795 <br />Zn, Dis (ug/1) 0.4 0.6 1,0 391.6 -- 199.16 2 <br />Note 1: There are no acute standards for dissolved arsenic, dissolved aluminum, total recoverable iron, and dissolved mercury therefore no assimilative <br />capacities were calculated far these pollutants of concern. <br />Note 2: The ambient water quality in Cripple Creek exceeds the standard for dissolved manganese and dissolved zinc. Amass balance cannot be done for <br />these parameters. The acute assimilative capacity far manganese must be set at [he acute water quality standard, 3677.8 ug/I. There is no azsimilative capacity <br />for these ammeters and dischar es must be limited to the standards. <br />The assinvlative capacities in Cripple Creek at the confluence with Arequa Gulch are included in the previous two <br />tables. These levels represent the greatest addition ofpollutants allowable from Arequa Gulch that wouldprovide <br />for attainment of standards in Cripple Creek. If these levels are not exceeded at AG2.0, located on Arequa Gulch <br />just above the confluence with Cripple Creek standards would be attained in Cripple Creek. <br />This assessment also considers the standards in Arequa Gulch. Arequa Gulch is a zero low flow stream segment. <br />Because there is no low flow contributor of pollutants or flow from upstream, the assimilative capacity of Arequa <br />Gulch is equal to the water quality standards. Table value standards were calculated using a hardness of400 mil. <br />The actual average hazdness at AG2.0 was 650 mg/1 from 37 data points however the Basic Standazds cap the <br />hazdness at 400 mg/1 for use in the equation. The following table, Table A-11, includes the assimilative capacities <br />for both streams. If these levels are attained at AG1.5, the standards in Arequa Gulch should be protected. <br />Table Il: <br />Summary of the Calculated Assimilative Capacities <br />Assimilative Ca aci effective January 20, 2003 in Parentheses <br />Parameter Chronic Assimilative <br />Capacity <br />in Cripple Creek <br />(ug/1) Acute Assimilative <br />Capacity <br />Cripple Creek <br />(ug/1) Chronic <br />Assimilative <br />Capacity in <br />Arequa Gulch <br />(u I Acute Assimilative <br />Capacity in Arequa <br />Gulch(ugR) <br />Al, Dis (ug/1) NA NA 11,000 11,000 <br />Cd, Dis (ug/1) 5.6 12.6 6.2 19.12 <br />Cu, Dis (ug/I) (---) t 26.0 29.28 49.62 <br />CN, Free (mg/1) No Standard 0.008 No Standard 0.005 <br />Fe, Trec (ug/l) 1498 No Standard 1000 No Standard <br />Pb, Dis (ug/1) 10.6 211.2 10.9 280.85 <br />Mn, Dis (ugQ) (---) t (---) I 6,300 (3,674) 18,500 (5,905) <br />Hg, Dis (ug/I) 0.028 No Standard 0.01 No Standard <br />Appendix A Page 12 of 13 <br />