The Missouri River, the longest river in the United States, is in trouble. A new study by the National Research Council, an independent institution that provides science and technology advice to the United States Congress, has found the river needs immediate action to restore its natural water flow or it will face continued degradation.

When Lewis and Clark explored the Missouri River nearly 200 years ago, they discovered a vast landscape with then previously unknown species. But the ecology of the river basin - which covers one-sixth of the continental United States has changed vastly over the last two centuries with the settling of the west and the construction in the last century of dozens of dams, levees and channels along the river.

The growth of agriculture, industry and urban centers in the floodplain has also seriously damaged the natural habitat and reduced the abundance of native species along the River.

The National Research Council report says that some losses, such as species that are now extinct, can never be restored.

"Perhaps exemplary of the decline of native species is the fact that three species in the basin are federally listed endangered species," said Steven Gloss, chairman of the committee that produced the report. "That is one indication of what we believe a symptomatic decline and its connection with its flood plain."

The National Research Council report says more water flow in the river would help the system recover, a recommendation supported by environmentalists and recreational users. But, farmers who grow crops on the floodplains and barge operators who transport goods on the river want to maintain the status quo.

Water flow is managed by the Army Corps of Engineers, and the report recommends that the Corps increase that flow immediately. However, Corps spokesman General David Festabend says the Corps cannot change water flow until proposed revisions in its master plan for river management are approved and in place.

"As much as we admire the National Academy of Science [National Research Council report], it doesn't have the legal authority of what we get from Congress or the judicial authority of what we get out of the Courts," he said. "And, the Endangered Species Act tells me I have to respond to a biological opinion. And the Fish and Wildlife Service has given us a biological opinion that tells us that the way the Corps runs the river right now puts three endangered species in jeopardy."

These are the same species mentioned in the National Research Council report. The Army Corps of Engineers must comply with the Endangered Species Act by 2003 or face possible court action.

The National Research Council report recommends an environmental management strategy called adaptive management. Committee Chairman Steve Gloss says adaptive management is an attempt to build agreement among all interested parties by adapting to changes in the economy and ecology, as well as in the latest scientific evidence.

"Our report emphasizes figuring out ways to reconnect the river with its critical habitat areas and producing flows that both make ecological as well as economic sense in the basin," he said. "And that those reconnections and the restoration of these physical processes really need to be implemented with full consensus in the adaptive management kind of environment where there is inevitable interaction between humans and communities and natural systems."

In the long run, the report calls on Congress to enact a comprehensive Missouri River protection act. Committee Chairman Steven Gloss says, the recovery could "stand as a significant example of large-scale river restoration not only in this country, but in the world."