OCR Text |
Show PART III PRESENT STATUS OF DEVELOPMENT Quality of water at the upper reaches near mountain divides is ex- cellent; downstream the quality is degraded as the result of hydrologic, geologic, and man-made influences. The average total dissolved solids of the Colorado River at Lees Ferry, Arizona, was 586 parts per million for 1941 to 1966, adjusted to present conditions of development. Some problems occur because of existing waterborne diseases, improper treatment of water and solid waste, radiological hazards, mosquitoes, and air pollution. Flood control measures in operation consisted of flood control stor- age of about 1.2 million acre-feet and multiple-use land treatment mea- sures on 1.8 million acres of watershed area. Substantial additional bene- ficial effects accrue from other reservoirs not operated specifically for flood control. 1965 Land Ownership and Use About two-thirds of the land was owned or administered by Federal and state governments, as illustrated by the chart entitled "Land Ownership and Administrative Status, 1965." There are 72.6 million acres, or 113,496 square miles, in the region. Multiple land use in 1965, with concurrent uses on some land, was as fol- lows. Multiple land uses--1,000 acres Cropland and pasture Irrigated 1,622 Dry 603 Livestock grazing 6o,442 Timber production!/ 9,419 Urban and industrial 331 Transportation and utilities 598 Developed recreation 71 Wilderness, natural, historic, and cultural Developed mineral production Developed fish and wildlife Military Classified watersheds Water area (kO acres or more) 2,636 37 299 lllf 258 1405 1/ Economic subregions-other figures hydrologic subregions. 26 |