listed species (the Fish and Wildlife Service opinions were issued as part of the environmental impact study process). This followed the Corps’ issuance of the Master Manual Draft Environmental Impact Statement, which recommended changes in the management of the dams and reservoirs. The Corps conducted public hearings on this draft document. These hearings revealed controversies and passionately-held beliefs surrounding the river’s many users. A consensus emerged that recognized the need for improved ecological monitoring and scientific knowledge to improve river management. Nevertheless, the National Environmental Policy Act environmental impact statement process—initiated when the Corps began revisions to its Master Manual in 1989—and a final revision of the Corps’ Master Manual for operation of the Missouri River system had not been completed in early 2002, nearly 14 years after the Master Manual revision process began. Congress, the Missouri River basin states, and the basin’s water users and interest groups disagree on the appropriate water release schedule (including timing, locations, and quantities of water) for the Missouri River’s mainstem reservoirs.

In 1999, with sponsorship of the U.S. Environmental Protection Agency (EPA) and the Corps of Engineers, the Water Science and Technology Board of the National Research Council (NRC) formed a committee of experts to help provide a better scientific basis for river management decisions in the Missouri River basin. This study complements similar NRC studies of the Columbia River basin, the Colorado River basin, the Florida Everglades, and the Upper Mississippi River. It also recognizes a growing public interest in redressing modifications made to large river ecosystems. This committee was given the following charge: