The U.S. Army Corps of Engineers recently completed its feasibility study for the Upper Mississippi River-Ilinois Waterway, which was one of the agency's longest and most complicated studies in its history. The first two reports from this WSTB committee reviewed analytical aspects of the Corps feasibility study. Water Resources Planning for the Upper Mississippi River and Illinois Waterway considers the broader issue of managing the multiple resources of the Upper Mississippi River and Illinois Waterway, especially with regard to several, recently-issued NRC reports on Corps of Engineers planning procedures. The report finds that a key issue regarding planning decisions on these river systems is the ambiguity related to several different pieces of legislation and acts that govern river management, and thus recommends that the administration and Congress clarify the federal intent for managing this river and waterway system. The report recommends an independent, retrospective reivew of the experience with a federal inter-agency Principals Group, which was convened to provide guidance to the Corps study. It is also recommended that the Corps strive to incorporate flexible, adaptive management principles through its entire water planning program, including operations of the lock and dam system.

In 1988, the U.S. Army Corps of Engineers began an investigation of the benefits and costs of extending several locks on the lower portion of the Upper Mississippi River-Illinois Waterway (UMR-IWW) in order to relieve increasing waterway congestion, particularly for grain moving to New Orleans for export. With passage of the Flood Control Act of 1936, Congress required that the Corps conduct a benefit-cost analysis as part of its water resources project planning; Congress will fund water resources projects only if a project's benefits exceed its costs. As economic analysis generally, and benefit-cost analysis in particular, has become more sophisticated, and as environmental and social considerations and analysis have become more important, Corps planning studies have grown in size and complexity. The difficulty in commensurating market and nonmarket costs and benefits also presents the Corps with a significant challenge. The Corps' analysis of the UMR-IWW has extended over a decade, has cost roughly $50 million, and has involved consultations with other federal agencies, state conservation agencies, and local citizens. The analysis has included many consultants and has produced dozens of reports. In February 2000, the U.S. Department of Defense (DOD) requested that the National Academies review the Corps' final feasibility report. After discussions and negotiations with DOD, in April 2000 the National Academies launched this review and appointed an expert committee to carry it out.

For over a century, the federal government has constructed water resource projects for a variety of purposes, including flood control, navigation, power generation, and irrigation. While most municipal and industrial water supplies have been built by non-federal entities, most of the large, federal water supply projects in the West, including Hoover and Grand Coulee dams, were constructed by the Bureau of Reclamation (Department of the Interior) to provide water for irrigation. Growing populations and changing values have increased demands on water supplies and river systems, resulting in water use and management conflicts throughout the country, particularly in the West, where the population is expected to increase 30% in the next 20-25 years. In many western states, agricultural needs are often in direct conflict with urban needs, as well as with water demand for threatened and endangered species, recreation, and scenic enjoyment. Debate over western water resources revolves around the issue of how best to plan for and manage the use of this renewable, yet sometimes scarce and increasingly sought after, resource. Some observers advocate enhancing water supplies, for example, by building new storage or diversion projects, expanding old ones, or funding water reclamation and reuse facilities. Others emphasise the need to manage existing supplies more efficiently through conservation, revision of policies that encourage inefficient use of water, and establishment of market mechanisms to allocate water. Recent proposals to expand the Upper Mississippi River-Illinois Waterway (UMR-IWW) a major transportation route for products moving to and from Illinois, Iowa, Minnesota, Missouri, and Wisconsin have met with significant controversy. Some of this controversy centres on the cumulative environmental effects of the current navigation system and the proposed expansion. The Upper Mississippi River System (UMRS), which includes the navigation channel and surrounding floodplain supports an unusually large number of species for a temperate river. The UMR-IWW navigation system alters UMRS habitat and contributes to a decline in the abundance of some species. For example, locks, dams, and other channel structures inhibit the movement of fish between and within river segments; fill side channels, backwaters, and wetlands with sediment; and suppress plant growth by reducing water clarity.