FIGURE 1-1 Missouri River basin, major tributary streams, and mainstem dam and reservoirs. © International Mapping Associates.

opment along tributary streams and for irrigation. In addition, private entities and the U.S. Department of Agriculture (USDA) built dams of different sizes on the tributaries further, affecting water flow and sediment transport. Also, the USDA and the states encouraged private landowners to implement practices that would hold water and sediments on their farms and ranches.

In the 1945 Rivers and Harbors Act, Congress authorized the Missouri River Bank Stabilization and Navigation Project (BSNP). This act resulted in channelization of most of the Missouri River below Sioux City, Iowa—a process that had begun in the nineteenth century—via a combination of dikes, revetments, and other engineering structures. Today, the dams and bank stabilization projects are maintained and operated by the Corps, Reclamation, and other entities. Management objectives of the system are hydropower generation, recreation within the pools and in reaches between the structures, reliable municipal and irrigation water supplies, fish and wildlife, and maintenance of a commercial navigation channel. In the process of impounding and channelizing the Missouri River, the Pick-Sloan dams and the BSNP projects have provided numerous economic and social