Lack of water was an obstacle to the initial settlement and development of the West. Rainfall was inadequate for dryland agriculture, and streamflows were erratic, providing little reliable flow in the absence of storage. By 1900 most of the West's easily irrigable lands were already developed, and even though development had focused on the most favorable sites, irrigation had been expensive and many irrigators and irrigation projects were hopelessly in debt. These conditions led many to conclude that greater federal support was needed to promote settlement of the West through irrigation. This support came initially through the Reclamation Act of 1902, which created the Reclamation Service--renamed the Bureau of Reclamation in 1923--to help family farms establish irrigation systems.
Today, nearly nine decades after passage of the original Reclamation Act, water scarcity remains a major obstacle to further development of the West. But, due in part to the efforts of the Bureau of Reclamation, current conditions are very different from those at the start of this century. About 40 million acres are now irrigated in the seventeen western states, with one-fourth of those acres receiving water from bureau projects. Irrigation accounts for nearly 80 percent of all freshwater withdrawn from western streams, lakes, and aquifers and for 90 percent of the region's consumptive use of water. All the good as well as many poor, dam and reservoir sites have already been developed, and the financial costs of developing new water supplies for offstream uses such as irrigation are high. Moreover, the environmental costs of building new dams and diverting more water are major obstacles to the construction of new water projects. Growing