Reconnaissance of chemical quality of surface water and fluvial sediment in the Dirty Devil River basin, Utah

The water-quality reconnaissance in the Dirty Devil River basin, Utah, covered an area of about 4,300 square miles (11,100 square kilo-meters). Data were obtained by the U.S. Geological Survey one or more times at 104 sites during the period July 1975 to September 1976; and during visits to 34 other sites during the same period, the streams were dry.

Precipitation was below normal in both 1975 and 1976 at weather stations at Emery and Capitol Reef National Park and was above normal in 1975 and below normal in 1976 at Hanksville. Streamflow was near normal in the Dirty Devil River basin in 1975 and was much below normal in 1976.

Rocks that crop out in the basin range in age from Permian to Quaternary. The Carmel Formation of Jurassic age and various members of the Mancos Shale of Cretaceous age are major contributors of dissolved solids to streams in the basin.

Major diversions are made from Muddy Creek for irrigation in the Emery area. Downstream reaches of Muddy Creek commonly receive only seepage and irrigation return flow. Three major irrigation diversions near Fremont commonly remove nearly all the flow from the upper Fremont River. Major flow accretions to the Fremont River in Bicknell Bottoms furnish water for additional diversions along the remaining length of the Fremont River.

The most pronounced change in chemical characteristics of water in streams in the Dirty Devil River basin occurs in a 15-mile (24-kilometer) reach of Muddy Creek between the major diversions 5 miles (8 kilometers) north of Emery and the point at which Highway 1-70 crosses Muddy Creek. Dissolved-solids concentrations at the diversions are generally less than 300 milligrams per liter and at the lower end of the reach are commonly greater than 2,000 milligrams per liter. Factors that contribute to the deterioration in the chemical quality of water in the Emery area are the soluble minerals in the rocks of Cretaceous age that crop out in the area, the major or total diversion of flow of Muddy Creek, and the irrigation of and return flow from soils that have commonly developed on material derived from gypsum-bearing marine shale. Dissolved-solids concentrations remain high to the mouth of Muddy Creek near Hanksville. Only one perennial stream--Salt Wash--enters Muddy Creek between Highway 1-70 and the mouth. The discharge of Salt Wash is usually 2.0 to 2.5 cubic feet per second (0.057 to 0.071 cubic meter per second), and the dissolved-solids concentration ranges from about 5,400 to 5,900 milligrams per liter.