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<br />. <br /> <br />. <br /> <br />must be taken to insure that future spills do not occur which <br /> <br />would impair the water quality of the river. <br /> <br />The Union Carbide uranium and vanadium mill on the San <br /> <br />Miguel River at Uravan discharges effluent which adversely affects <br /> <br />the water quality of the Dolores. Exfiltration of ammonia from <br /> <br />ponds adjacent to the San Miguel exceeds state and federal stand- <br /> <br />ards of 0.02 mg/l. Concentrations of 0.25 mg/l are presently <br /> <br />considered <br /> <br />~~ <br /> <br />toxic to fish life. <br /> <br />The main effect of the ammonia on the Dolores is stimu- <br /> <br />lation of algal growth resulting in an impairment of the esthetic <br /> <br />qualities of the water a short distance below the confluence. <br /> <br />Discussions are currently underway between the company and federal <br /> <br />and state agencies in order to determine future ammonia effluent <br /> <br />limitations, and it is reasonable to expect that future ammonia <br /> <br />levels will be lower than their present levels. <br /> <br />Salinity and suspended sediment <br /> <br />The most severe water quality problems of the Dolores River <br /> <br />on salinity and suspended sediment discharge. Both result pri- <br /> <br />marily from natural sources, and, therefore, do not effect the <br /> <br />proposed designation of the Dolores as a wild or scenic river. <br /> <br />Because of the magnitude of these two water quality parameters, <br /> <br />and plans to reduce the salinity of the Dolores, a discussion <br /> <br />of the souces of sediment and dissolved solids and their effects <br /> <br />on the river ecosystem is appropriate. <br /> <br />Dissolved solids discharge to the Colorado River from the <br /> <br />Dolores River averages 600,000 tons per year which is 11 percent <br /> <br />-3- <br /> <br />~ <br />~ <br />