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Improvement to the quality of Coal Creek by the AMAX Corporation treating wastewaters of the abandoned Keystone Mine has resulted in the restoration of aquatic life in Coal Creek. The quality of water in the Slate River below Coal Creek has also been improved as a result of this treatment. Two new reservoirs are now under construction, Ridgway in the Gunnison drainage and McPhee on the Dolores River. Reclamation is monitoring the inflow to these reservoirs and has agreed to install an aeration system to prevent Ridgway Reservoir from becoming anaerobic if a condition is found which allows heavy metals and trace elements to re-enter the water in solution. Depending on the biological availability of the pollutants from the sediments into the food chain, the fisheries, or at least the edibility of the fish flesh, may be impaired in Ridgway Reservoir and, possibly, to a lesser extent, in McPhee Reservoir. If these reservoirs act as permanent traps for heavy metals, downstream water quality could benefit. Municipal and industrial water from Ridgway Reservoir will be provided by an exchange of the irrigation water for a higher quality source. This will reduce the impacts from metal pollutants. Several major sources of salt loading to the Colorado River are found within Colorado. They include saline springs on the Dolores River in the Paradox Valley, Glenwood-Dotsero Springs, and agricultural return flows in the Grand Valley, McElmo Creek, and Lower Gunnison areas. D. Arizona Water quality along the Colorado River is protected for agriculture, aquatic life, drinking water supply, fishing, full body contact recreation, and wildlife uses by Arizona water quality standards. To determine whether or not these standards are being met, a sampling program has been implemented. In 1983 and 1984, 13 locations were sampled in the Colorado River in Arizona. Six of these locations were sampled ten or more times; seven locations were sampled one to nine times. The parameters sampled were general field data, general chemistry, nutrients, dissolved and total metals, microbiology, radiochemicals, and priority pollutants. The sampling program has helped identify areas of concern within Arizona and is described in the State Water Quality Assessment Report prepared to satisfy Sec. 305(b) of the Federal Clean Water Act. There is continued concern about meeting secondary drinking water quality criteria. At Parker Dam, average concentrations of some constituents exceed the u.S. Public Health Service drinking water recommendations. A second concern, now that Colorado River water is being delivered to Central Arizona through the Central Arizona project, is salinity. Municipal entities have raised concerns over any increase in salinity. They fear that an increase in salinity could limit their use of Colorado River water. E. Nevada The Colorado River met water quality standards, provided for protection and propagation of fish and wildlife, and allowed recreational activities in and on the water. The high water level in Lake Mead continues to contribute III-4