Rediscovering the Missouri River
The Missouri River touches the lives of millions of people as it makes its 2,341-mile journey from its headwaters in Montana to its confluence with the Mississippi River near St. Louis. Along the way, it passes through six dams and the largest reservoir system in North America, draining one-sixth of the land area of the United States.
The Missouri River of today is far different from the one that carried Lewis and Clark on their epic journey nearly two hundred years ago. During the "Corps of Discovery" expedition, which lasted from May 1804 to September 1806, the explorers described an abundance of amphibians, reptiles, fish, birds, mammals and habitats. Much of the diversity of the Missouri River ecosystem has since been lost to construction of dams on the upper river and to channelization and bank stabilization. These "improvements" have dramatically altered the pattern of natural flows and isolated the river from its flood plain in order to achieve navigation and flood control objectives.
The magnitude of changes in the Missouri River is staggering. During the 1900s, channelization shortened the Missouri River channel from Sioux City, Iowa, to St. Louis by 127 miles, with drastic reductions in acreage of sandbars and islands. It has been estimated that one square mile of wetlands, oxbow lakes, meandering river, islands, and mud flats was lost for each linear mile of shortened river channel. Approximately 552,000 acres (83 percent) of the channel and its erosion zone have disappeared as a result of rock dikes and earthen levees. By the 1970s, about 85 percent of the former flood plain between Sioux City and St. Louis was being managed intensively for agriculture. Small wonder the Missouri River has been named one of the nation's most endangered rivers!
These alterations of the natural river have severely reduced the amount and quality of habitat for fish and wildlife, jeopardizing the survival of species such as the pallid sturgeon, a fish which uses shallow sand and gravel areas adjacent to sandbars, and the interior least tern and piping plover, which require sandbars and sand islands for nesting and brood-rearing. Sandbars and shallow-water habitats were among the most common and seasonally productive fish and wildlife habitats of the Missouri River prior to development.
The U.S. Army Corps of Engineers has been studying ways to improve management of the Missouri River system. Last year, the Department of Conservation proposed reducing releases from Gavins Point Dam in South Dakota to achieve a lower flow of 41,000 cubic feet per second at Kansas City from August 1 to September 15, in three of every five years. The intent of the proposal is to recover a measure of the historic low summer flow that is so beneficial to fish and wildlife. The benefits of reduced flows were apparent this past August, when unusually dry upstream conditions exposed hundreds of acres of sandbars and islands in Missouri's portion of the river, increasing important shallow-water habitat for fish and wildlife. The lowered river levels also improved fishing and other river recreation while still allowing for navigation and other commercial uses.
Such beneficial river conditions are rare under the current Water Control Plan. We believe that improving the health of the river will require a fundamental change in river management.
The Corps recently published the Missouri River Master Manual Revised Draft Environmental Impact Statement (RDEIS). The document describes environmental effects of six alternative operating plans for the Missouri River. Conservation Department staff are carefully reviewing the report to determine which option best avoids further jeopardy to endangered species while providing needed benefits to the Missouri River ecosystem.
We are pleased that some of the alternatives contained in the RDEIS appear to capture the essence of the Department's proposal for lower summer flows, with only a modest increase in spring river levels once in every three years. The Corps would have the flexibility to modify flows to avoid flooding or other adverse impacts, based on monitoring and evaluation of sound scientific data, impacts of weather and downstream river conditions. A summary of the RDEIS is available on the web at <www.nwd.usace.army.mi>.
As Missouri prepares to celebrate the 200th anniversary of the Corps of Discovery, the great river that beckoned Lewis and Clark has been sorely degraded. We can restore a measure of its former diversity and achieve significant benefits for fish and wildlife with modest changes in river flows and a continued emphasis on habitat restoration. If we rise to the challenge, the Mighty Missouri may truly become a river of many uses.
John W. Smith, Deputy Director