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.

Large-Scale Ecosystem Restoration presents case studies of five of the most noteworthy large-scale restoration projects in the United States: Chesapeake Bay, the Everglades, California Bay Delta, the Platte River Basin, and the Upper Mississippi River System. These projects embody current efforts to address ecosystem restoration in an integrative and dynamic manner, at large spatial scale, involving whole (or even multiple) watersheds, and with complex stakeholder and public roles. Representing a variety of geographic regions and project structures, the cases shed light on the central controversies that have marked each project, outlining • the history of the project • the environmental challenges that generated it • the difficulties of approaching the project on an ecosystem-wide basis • techniques for conflict resolution and consensus building • the ongoing role of science in decision making • the means of dealing with uncertainties A concluding chapter offers a guide to assessing the progress of largescale restoration projects. Large-Scale Ecosystem Restoration examines some of the most difficult and important issues involved in restoring and protecting natural systems. It is a landmark publication for scientists, policymakers, and anyone working to protect or restore landscapes or watersheds.

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.

With contributions from a wide array of economists, ecologists, and government agency professionals, Economics and Ecological Risk Assessment: Applications to Watershed Management provides a multidisciplinary approach to environmental decision-making at a watershed level. It introduces the fields of ecological risk assessment (ERA) and economic ana