Criteria, acronyms
A. Criteria, standards
1. Water temperature
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62.6 F, Colorado (CO) chronic criterion.
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71.1 F, CO acute criterion.
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64.6 F, brook trout chronic criterion.
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64.9 F, rainbow trout chronic criterion.
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67.3 F, brown trout chronic criterion.
2. Water quality
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pH: 6.5-9.0.
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Dissolved oxygen (DO): 6.0 mg/l; 7.0 mg/l, during spawning.
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E. coli: 126 per 100 ml.
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Total coliform: 200 per 100 ml.
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Nitrate: 10 mg/l.
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Ammonia: calculated based on pH.
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Metals (arsenic, cadmium, copper, lead, manganese, silver, zinc): calculated based on hardness.
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Selenium: 4.6 ug/l.
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Total nitrogen as nitrate: 1.25 mg/l (interim standard).
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Total phosphorus as phosphate: 0.11 mg/l (interim standard).
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(Total coliform: 200 per 100 ml).
B. Acronyms, abbreviations
1. General
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CCR, Code of Colorado Regulations.
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CS-1, cold stream tier 1.
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TVS, table value standard.
2. Water temperature
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30T, 30-minute temperatures.
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WAT, weekly average temperatures.
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MWAT, maximum weekly average temperature.
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TAT, two-hour average temperatures.
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MTAT, maximum two-hour average temperature.
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DM, daily maximum; same two-hour calculation as MTAT.
3. Water quality
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DO, dissolved oxygen.
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E. coli, Escherichia coli.
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M&E, monitoring and evaluation.
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mg/l, milligrams per liter, equivalent to parts per million.
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ug/l, micrograms per liter, equivalent to parts per billion.
Sources
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Code of Colorado Regulations, Water Quality Control Commission, 5 CCR 1002-31, Regulation No. 31, "The Basic Standards and Methodologies for Surface Water" (Rule 31).
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Code of Colorado Regulations, Water Quality Control Commission, 5 CCR 1002-34, Regulation No. 34, "Classifications and Numeric Standards for San Juan River and Dolores River Basins" (Rule 34).
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Todd, A. S., M. A. Coleman, A. M. Konowal, M. K. May, S. Johnson, N. K. M. Vieira, and J. F. Saunders, "Development of New Water Temperature Criteria to Protect Colorado's Fisheries," Fisheries, vol. 33, no. 9, pp 433-443, 2008.
