WASHINGTON, D.C., Jan. 17, 2002 -- Degradation of the Missouri River ecosystem will continue unless the river's natural water flow is significantly restored, says a new report from the National Academies' National Research Council.
Congress should enact legislation to ensure that federal officials manage the river in a way that improves ecological conditions, said the committee that wrote the report.
"Scientific discoveries about the Missouri River were first documented 200 years ago when Lewis and Clark returned from their expedition with descriptions of several new species," said committee chair Steven Gloss, program manager, Grand Canyon Monitoring and Research Center, U.S. Geological Survey, Flagstaff, Ariz.
"More recent research clearly demonstrates that from an ecological perspective, this river is in a serious state of decline. The river is too big and complex for us to know where the point of irreparable environmental change lies, or how close the river may be to passing that point. But we do know that to repair the existing damage, we must re-establish some degree of natural hydrological processes, and do so in a manner based on the latest scientific information."
The construction of dozens of dams in the Missouri River basin, the channelization of the lower 735 miles of the river, the building of levees, and other human activities over the past century have led to significant reductions in the natural habitat and abundance of native species along the Missouri River, the report says.
For example, nearly 3 million acres of habitat on the river's banks and floodplain have undergone human alterations, and sharp reductions in natural vegetation have resulted from cropland expansion in the floodplain.
Two bird species that depend on the river's habitat are listed as endangered, and of the 67 fish species native to the river, 51 are now listed as rare, uncommon, or decreasing in numbers, and one is an endangered species. In some parts of the river and its massive reservoirs, there are more nonindigenous sport fish than native fish. In other parts, the ecologically beneficial rise and fall in water flow each season no longer occurs.
And perhaps most importantly, sediment flow -- a hallmark of the river and the reason it was nicknamed "The Big Muddy" -- has been dramatically reduced, in some places by more than 100 million tons a year. Sediment flow is crucial to maintaining a river system's geological and biological structure and functions.
Restoring natural water flow in large rivers to boost the ecosystem is an environmental-management strategy still in its infancy, but scientists know that the natural rise and fall in water levels is essential to biological productivity in large rivers. Moreover, some smaller rivers have exhibited rapid ecological responses when more natural water flows were restored, the report says.
In the Kissimmee River in Florida, for example, plant communities rebounded and fish and insect populations grew when natural hydrological processes were reintroduced in the early 1980s. More recently, the breaching of Edwards Dam on Maine's Kennebec River resulted in increases in the abundance of certain bird and fish species.
The U.S. Army Corps of Engineers operates the six large dams that are the centerpiece of the Missouri River water storage system, the largest in North America. The agency's water-release schedule for the dams enhances navigation for barges by maintaining a nine-foot-deep channel from Sioux City, Iowa, downstream to St. Louis -- even though barge traffic has decreased steadily since 1977.
This emphasis on navigation has put the Corps at the center of controversy between those who want greater amounts of natural water flow and those who prefer the status quo. Environmentalists generally want the Corps to allow greater natural water flow to restore the river's ecosystem, and recreational users and the tourist industry say low water levels caused by the Corps' restrictions hamper fishing, swimming, and boating.
Farmers downstream from the dams, however, worry that more water will cause flooding that could damage their crops.
Guidance for the Corps' water-release schedule is established in what it calls its "Master Manual." The agency began to revise the manual 14 years ago but has not finished because of disputes among various stakeholders. The Research Council report calls for a moratorium on further revisions of the manual until such changes reflect a science-based approach known as adaptive management.
It also says that current efforts by the Corps, U.S. Fish and Wildlife Service, and several state agencies to preserve and restore habitat along the river may be a good first step, but are insufficient for making noticeable gains.
Adaptive management is gaining favor among natural-resources administrators because it enables managers to adapt decisions to changing social and economic situations as well as the latest scientific evidence. It emphasizes the use of carefully designed and monitored experiments to improve understanding of how policy decisions affect ecosystems.
The report recommends that such experiments on the Missouri River should begin as soon as possible. Although the river's broad ecological patterns are well-understood, these experiments would shed light on some scientific uncertainties, especially how the river may respond to actions designed to improve its ecosystem.
The adaptive-management strategy should consider environmental goals on par with economic ones and should be directed by a formal group of all stakeholders, the report says. In addition to the Corps, the group should include at least the U.S. Environmental Protection Agency, the U.S. Department of Energy, the U.S. Bureau of Reclamation, the U.S. Fish and Wildlife Service, the National Park Service, American Indian tribes, state governments, local municipalities, farmers, environmental and recreational groups, and the barge industry.
The stakeholder group should receive input from an independent panel of scientists to help resolve uncertainties and ensure that the group is adhering to adaptive-management principles.
A Missouri River Protection and Recovery Act, if passed by Congress, would help keep river managers focused on improving the state of the ecosystem, the report says. Congress also should establish clear lines of authority for the agencies involved and provide sufficient funding to implement an adaptive-management approach.
In addition, Congress should authorize the Corps to set different water-release schedules for different parts of the river, the committee said. For example, it may be determined that the navigation benefits in certain places are relatively small -- especially in upstream areas where barge traffic is light -- compared with the ecological benefits that could be realized from greater natural water flow.
The study was sponsored by the U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency. The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering. It is a private, nonprofit institution that provides science and technology advice under a congressional charter. A committee roster follows.
The report The Missouri River Ecosystem: Exploring the Prospects for Recovery is available on the Internet at http://www.nap.edu. Copies will be available for purchase later this winter from the National Academy Press; tel. (202) 334-3313 or 1-800-624-6242. Reporters may obtain a pre-publication copy from the Office of News and Public Information (contacts listed above).
