Intent To Prepare a Draft Environmental Impact Statement (DEIS), Lock and Dam 3 Mississippi River Navigation Safety and Embankments Projects

AGENCY:

U.S. Army Corps of Engineers, DoD.

ACTION:

Notice of intent.

SUMMARY:

Lock and Dam 3 is a navigation dam and lock on the Mississippi River six miles upstream from Red Wing, Minnesota. The lock and dam was built on a bend in the river, and completed in 1938. Its position on a bend in the river makes downbound navigation difficult, because of an outdraft current that tends to sweep towboats and barges away from the lock toward the gated part of the dam. The outdraft condition has resulted in a number of accidents, and has been cause for concern for many years. A related problem with Lock and Dam 3 is maintaining the structural integrity of a set of three earthen embankments that connect the gated part of the dam to high ground on the Wisconsin side. The upstream embankment is federally-owned and contains a series of rock overflow sections. The intermediate and downstream embankments are privately owned. These embankments impound Marsh and Gantenbein Lakes, and separate them from the Mississippi River. The three Wisconsin side embankments divide the eight-foot head at the dam into three steps, and work together as part of Lock and Dam 3. The downstream embankment is eroding and is expected to fail in the next decade or two. Failure of the downstream embankment would threaten the intermediate and upstream embankments.

FOR FURTHER INFORMATION CONTACT:

Questions pertaining to the issues about the DEIS may be addressed to Mr. Robert Whiting, Chief, Environmental and Economic Analysis Branch, St. Paul District, U.S. Army Corps of Engineers, 190 5th Street East, St. Paul, MN 55101, Telephone: (651) 290-5264.

SUPPLEMENTARY INFORMATION:

1. The potential exists for towboat operators to lose control of their tows because of the outdraft current. Barges have broken loose and lodged in the dam gate bays, rendering the dam gates inoperable, causing the water level in the navigation pool to rise, overflowing the earthen embankment. This kind of event occurred in 1993, resulting in significant erosion in the upper embankment near the gated part of the dam and in the lower embankment.

2. Two projects to address the navigation safety and embankments concerns have been proposed by the St. Paul District and approved by Corps of Engineers Headquarters. A ported guardwall was proposed to guide downbound towboats into the lock. This project has not been funded. The St. Paul District also recommended reconstructing the Wisconsin-side embankment, following a downstream alignment along the tailwater and the southern boundary of Gantenbein Lake. Recent surveys in the tailwater identified the presence of a species-rich mussel bed, including state-listed endangered species. In an effort to address the navigation safety and embankment concerns at Lock and Dam 3, the St. Paul District is conducting a re-evaluation of these related problems.

3. Significant resources and issues to be addressed in the DEIS will be determined through coordination with Federal, State, and local agencies, the general public; interested private organizations, industry, and the Prairie Island Dakota Community. Anyone who has an interest in participating in the development of the DEIS is invited to contact the St. Paul District, Corps of Engineers.

4. Major issues identified to date for discussion in the DEIS are:

a. Structural integrity and operational reliability of Lock and Dam 3.

b. Risk of navigation accidents, erosion of embankments, and accidental drawdown of Pool 3.

c. Recreational boating opportunity and safety.

d. Natural resources including the fishery, native mussels, wildlife, aquatic and floodplain habitats.

e. Water quality, contaminants, and sediment transport processes.

5. Additional issues of interest may be identified through public and agency meetings. A notice of those meetings will be provided to interested parties and to local news media.

6. The effort to jointly address the related navigation safety and embankments problems at Lock and Dam 3 is considered major in scope. Depending on the alternative plan proposed, the project could have significant effects on navigation, public safety, regional economics, floodplain wetlands, the fishery, native mussels and wildlife.

7. An environmental review will be conducted according to National Environmental Policy Act of 1969, Council of Environmental Quality Regulations, and applicable laws and regulations. The DEIS will be available to the public in the summer of 2001.