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Mountain Coal and Bear Coal Water Quality Assessment CO-0038776 and CO-0044377 <br />Table A-4 <br />TVS-Based Metals Water Quality Standards for the North Fork of the Gunnison River i <br />Based on the Table Value Standazds Contained in the Colorado Department of Public Health <br />and Environment Water Quality Control Commission Regulation 35 <br />- In-Stream Wafer - <br />Parameter Quality Standard Formula Used <br /> T20llt 1.8 Ug/1 [].13667-0.041841n(hazdness)}[e(1.128Qn(hardness))-3.828)] <br />Cadmium, Dissolved <br />Clll'On1C <br />1.4 Ug/1 <br />[1.10167-0.041841n(hardness)J[e (0.7852(In(hazdness))-2.715)] <br />HeX3V alerit ChTOmlllm, Acnte 16 llgll Numeric standards provided, formula not applicable <br />D1SSO1Ved ChrOmC 11 Ugl] Numeric standards provided, formula not applicable <br /> Acute 7.3 Ug/1 e (0.9422(in(hazdness))-1.7408) <br />Copper, Dissolved <br />ChronlC <br />5.1 Ilg/1 <br />a (0.8646(ln(hardness))-1.7428) <br /> ACUte 31 Ug/1 [L46203-0.1457121n(hardncss)][e (1173(1n(hardness)}1.46)] <br />Lead, Dissolved <br />ChrORIC <br />1.2 llg/1 p.z73(In(hardness)}a.7os)J <br />[1.46203-0.1467I21n(hardness)J[e <br />Manganese ACUte 2401 Ug/1 e(0.3331(In(hardness))+6.4676) <br /> Acute 269 ug/1 e (0.846(In(hardness))+2.263) <br />Nickel, Dissolved <br />Chronic <br />30 ug/1 <br />e (0.846(ln(hardness)),°O.OSS4) <br /> Acnte -18 Ug/l Numeric standards provided, formula not applicable <br />Selenlllm, D1SSOlved <br /> CbrORIC 4.6 Ag/1 Numeric standards provided, formula no[ applicable <br /> Acute 0.66 ug/1' ~ e ('.72('imltardmess))-6.52) ~ <br />Silver, Dissolved <br />TIOUt <br />0.024 ug/1 <br />e(I'72(ln(hardness)}10.51) <br /> ACllte 67 ug/1 e (0.8473(ln(hardness))+0.8618) <br />Zinc, Dissolved <br />Clll-On1C <br />6$ Ug~l <br />e(0.8473(In(hardness))+0.8699) <br />In the absence of available data downstream of discharge locations, the mean hardness for stream <br />segment COGUNF06 (including Sylvester Gulch, West Sylvester Gulch, the DryFork ofMinnesota <br />Creek, and Lone Pine Gulch) was determined to be 400 mg/1 based on the Rationale for <br />Classifications, Standards and Designations of Segments of the Gunnison and LowerpotoresRiver <br />Basins, which determined this hardness for stream segment COGUNF06 using comparable <br />watersheds. This hazdness value and the formulas contained in the TVS were used to calculate the <br />in-stream water quality standards for metals with the results shown in Table A-5. <br />Appendix A Page 7 of 20 Last Revised 3/9/2004 <br />