HYDRO28372

• Permit No: C1980007
• IBM Index Class Name: Hydrology
• Doc Date: 4/19/2004
• Doc Name: Exhibit 7 NPDES Permit
• From: Colorado Health Department of Public Health & Environment
• To: Mountain Coal Company
• Permit Index Doc Type: NPDES
• Media Type: D
• Archive: No

Mountain Coal and Beaz Coal Water Quality Assessment CO-0038776 and CO-0044377
Table A-11
Ammonia Assimilative Capacities for the North Fork of the Gunnison River
at the Mountain Coal Outfa11004
~aramefer„ !. Q~ bets.) Qz f~.~s), ~Q3lrfs~..: ~ Mi' °~3 ,,, .~2 s
NH3, Tot (mg/1) Jan 43 0.28 43.28 0.065 0.70 98
NH3, Tot (mg/I) Feb 44 0.28 44.28 0.065 0.60 85
NH3, Tot (mg/1} Mar 47 0.28 47.28 0.065 0.40 57
NH3, Tot (mg/1) Apr 70 0.28 70.28 0.065 0.40 84
NH3, Tot (mg/1) May 234 0.28 234.28 0.065 0.30 197
NH3, Tot (mg/1) Jun 223 0.28 223.28 0.065 0.30 187
NH3, Tot (mg/1) Jul 57 0.28 57.28 0.065 0.30 48
NH3, Tot (mg/1) Aug 43 0.28 43.28 0.065 0.30 36
NH3, Tot (mg/1) Sep 43 0.28 43.28 0.065 0.30 36
NH3, Tot (mg/1) Oct 52 0.28 52.28 0.065 0.30 44
NH3, Tot (mg/1) Nov 45 0.28 45.28 0.065 0.30 38
NH3, Tot (mg/1) Dec 43 0.28 43.28 0.065 0.50 67
Table A-12
Ammonia Assimilative Capacities for the North Fork of the Gunnison River
at the Mountain Coal Internal Outfa11007
Parameter - QI (,~.fs) ; Q z ,,(efs} Q s (~.fs,) ` Ml - Ms k Mz .,
NH3, Tot (mg/1) Jan 43 0.016 43.016 0.065 0.70 1,707
NH3, Tot (mg/1) Feb 44 0.016 44.016 0.065 0.60 1,472
NH3, Tot (mg/1) Mar 47 0.016 47.016 0.065 0.40 984
NH3, Tot (mg/I) Apr 70 0.016 70.016 0.065 0.40 1,466
NH3, Tot (mg/1) May 234 0.016 234.016 0.065 0.30 3,437
NH3, Tot (mg/1) Tun 223 0.016 223.016 0.065 0.30 3,276
NH3, Tot (mg/1) Jul S7 0.016 57.016 0.065 0.30 837
NH3, Tot (mg/1) Aug 43 0.016 43.016 0.065 0.30 632
NH3, Tot (mg/1) Sep 43 0.016 43.016 0.065 0.30 632
NH3, Tot (mg/1} Oct 52 0.016 52.016 0.065 0.30 764
NH3, Tot (mg/1) Nov 45 0.016 45.016 0.065 0.30 661
NH3, Tot (mg/I) Dec 43 0.016 43.016 0.065 0.50 1,170
Appendix A Page 19 of 20 Last Revised 3/9/2004