For the past few years, the Corps has been working on what is known as the Restructured Upper Mississippi River-Illinois Waterway Feasibility Study, the heart of which is a multibillion-dollar proposal to double the length of up to a dozen locks on the river. The Research Council first reviewed the feasibility study in 2001 during controversies over the accuracy of models being used by the Corps to justify lock expansion based on increased demand for barge transportation. More than 100 million tons of cargo-half of it grain destined for international markets, the other half goods such as construction materials, coal, and chemicals-are shipped along the navigation system each year. The locks, which along with dams allow barges to traverse uneven river depths, were originally designed for "tows" of barges up to 600 feet long, but the length of a typical tow has increased, forcing the Corps to look for ways to relieve congestion. The book finds the U.S. Army Corps of Engineers has made good progress in broadening its proposed plan for navigation improvements on the Upper Mississippi River-Illinois Waterway system to give greater consideration to ecological restoration. However, the plan still does not provide sufficient economic justification for expanding locks on the rivers because of flaws in the models the Corps used to predict demand for barge transportation. Little attention is paid to inexpensive, nonstructural navigation improvements that could help better manage existing levels of barge traffic. The revised plan has been usefully expanded to include many creative and potentially useful ecosystem restoration measures. These measures, however, should be more firmly grounded in river science principles and more broadly consider ways the river's ecology might affect or be affected by navigation, recreation and other uses.

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.