The newly created Reclamation Service was placed under the U.S. Geological Survey and lost no time in proposing irrigation developments. Using the previous surveys of potential reservoir sites initiated by Powell, the service authorized four projects its first year and an additional sixteen by the end of 1905. Table 1-2 shows the total irrigated acreage in the seventeen western states for each decade starting with 1890, along with the acreage served by federal water supplies. As the table indicates, there were about 13.5 million acres of private irrigation development in 1910, the first year that information regarding federally supplied water was provided by the census. The percentage of irrigated acreage in the West that received some water from the Bureau of Reclamation rose to 21 percent of the total acreage in the West by 1949 and has remained approximately the same since that time. In 1978 the Bureau of Reclamation supplied irrigation water to about 9.6 million acres out of a total of 43.6 million irrigated acres in the seventeen western states. Not all of this is a "full" irrigation supply; much is in the form of a "supplemental" supply designed to augment local sources developed by irrigation districts or by individuals.
Table 1-3 shows the distribution of irrigated acreage among the seventeen western states in 1977 and indicates whether that acreage received a full irrigation supply from the bureau, a supplemental supply, or both. In two states, Idaho and Washington, more than 40 percent of the irrigated acreage receives some federally supplied water. In contrast, less than 10 percent of the acreage irrigated in Kansas, Nebraska, Oklahoma, and Texas receives federally supplied water.
From the beginning of the reclamation movement, the appropriate role for the federal government in irrigation development in the arid western states was a subject of congressional debate. Up through the late 1880s, there was strong skepticism toward any federal assistance to irrigation, except possibly for preventing potential reservoir sites from being homesteaded. John Wesley Powell had hoped that by means of surveys, planning, and land withdrawals, the federal government could structure efficient private development of irrigation in the western states, but the pace of settlement simply was too rapid to accommodate his plan and Congress overturned it.