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FOOTNOTES 002539 Table 10 (cont.): Table value standards for the San Juan and Dolores River basins, Colorado (1) Metals are stated as dissolved unless otherwise specified. (2) Hardness values to be used in equations are in mg/I as calcium carbonate. The hardness values used in calculating the appropriate metal standard should be based on the lower 95 per cent confidence limit of the mean hardness value at the periodic low flow criteria as determined from a regression analysis of site-specific data. Where insufficient site-specific data exists to define the mean hardness value at the periodic low flow criteria, representative regional data shall be used to perform the regression analysis. Where a regression analysis is not appropriate, a site-specific method should be used. In calculating a hardness value, regression analyses should not be extrapolated past the point that data exist. (3) Both acute and chronic numbers adopted as stream standards are levels not to be exceeded more than once every three years on the average. (4) FT = 10.03 (20-TCAPI; TCAP less than or equal to I less than or equal to 30 FT = 10.03 (20.T); Q less or equal to I less than or equal to rCAP TCAP = 200 C cold water aquatic life species present TCAP = 250 C cold water aquatic life species absent FPH = 1; ft less than Iili less than or equal to II FPH 1 + 1 0{7 A-pH); Q.& less than or equal to Iili less than or equal to ft 1.25 FPH means the acute pH adjustment factor; defined by the above formulas. FT means the acute temperature adjustment factor, defined by the above formulas. T means the temperature measured in degrees Celsius TCAP means temperature CAP; the maximum temperature which affects the toxicity of ammonia to salmonid and non-salmonid fish groups. NOTE: If the calculated acute value is less than the calculated chronic value, then the calculated chronic value shall be used as the acute standard. Taken from Colorado Water Quality Control Commission 1993b 37