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16 '~. HYDROLOGIC AND HUMAN ASPECTS OF THE 1976-77 DROUGHT The number of livestock on many farms in several States was reduced to conserve water, and water; was hauled to supply those retained. Some animals were moved to places with suf- ficient water, and ranchers received financial assistance from the Federal Disaster Assist- ance Administration or the Department of Agriculture for the move. Water for Irrigation Irrigation-water withdrawals amount to roughly twice the water withdrawn for public, rural, and industrial uses combined, excluding water used by electric utilities in power gen- eration. Ground water supplies 40 percent of the irrigation withdrawals nationwide; but in eight western States in the drought areas, ground-water withdrawals normally average 32 percent. The first effect of a drought on agriculture is low soil moisture caused by the below normal rainfall. The additional irrigation required depletes the reserves in both surface- and ground-water reservoirs. Where surface supplies were practically exhausted, additional wells were drilled or existing wells were deep- ened. The increased use of ground water, though expensive, was enough to produce near- normal crop yields in many areas. Irrigation generally is considered a lower beneficial use than municipal use; so in some places irrigation diversions were reduced to provide water for municipalities. Conversely, the California Aqueduct was shut down south of the Tehachapi Mountains south of Bakers- field because additional water was available to southern California from the Colorado River. The additional water remaining in the San Joaquin Valley was used mainly for agricul- ture. In Idaho and Washington, some temporary redistributions of irrigation water were made. To save orchards and vineyards, they were irrigated rather than field crops. Also, irri- gated acreage was reduced or crops needing less water were planted in anticipation of decreased water supplies. Very low soil moisture because of the longer than normal periods between rains during the growing season in the Midwest stunted corn (fig. 8) and other farm products. Water for Hydroelectric Power Hydroelectric power is generated in 46 of the 50 states; therefore a widespread drought will affect seriously the ability of utilities to generate hydroelectric power. When storage in a reservoir is drawn down, the head on the generator is reduced and less power is pro- duced. The water level was lowered below the intakes to a few powerhouses in California, and power generation ceased. At other sites, the number of hours that power was generated had to be reduced. The reduced hydroelectric generation re- quired increased use of natural gas and oil at steam generating plants which added millions of dollars to the cost of producing electrical energy. The additional cost was passed on to the consumers when rates were raised. "Rolling brown outs" were expected in California, and electric-utility customers were advised of the proposed schedules. "Rolling . brown outs" are planned periods of a few hours when electric service to different areas or to different classes of customers would be inter- rupted on a scheduled rotation to reduce the demand for electricity and therefore reduce the water use by hydroelectric plants. How- ever, no "brown outs" occurred. Reduced hydropower output in the Columbia River basin affected some of the large consumers such as aluminum plants. Cutbacks in industry that is dependent on electric power increased the number of unemployed. Water for Forests Drought conditions were severe in many of the nation's forests; therefore, the fire season started earlier than usual-as early as April in Idaho. The larger fires in 1976 in California occurred in June and July burning 85 percent of the 165,000 acres burned in 1976. Normally only 25 percent of the acreage burned annually is burned by July 15. The obvious results of fires can be seen im media tely, but the secondary results of fires will not be known for awhile. When rains fi- nally come, erosion of hillsides, head and bank cutting along streams, deposition of sediment and debris, and flooding will occur in various degrees along streams draining the burned- over areas.