Legendary Weaver Bottoms Expected To Reap Benefits from Pool 5 Drawdown (2005-02-11)

Tom Conroy Information Officer DNR Southern Region 261 Hwy 15 South New Ulm MN 56073 507/359-6014 tom.conroy@dnr.state.mn.us

February 11, 2005

For additional information, contact: Tim Schlagenhaft, DNR Mississippi River Team Leader, Rochester: 507-280-5058.

Legendary Weaver Bottoms Expected To Reap Benefits from Pool 5 Drawdown

Legendary Weaver Bottoms, once a waterfowl and fish Mecca on the Mississippi River, is expected to reap important benefits from a planned pool drawdown on the river next summer.

Tim Schlagenhaft, Mississippi River Team leader with the Department of Natural Resources (DNR) and chair of the Water Level Management Task Force, said the task force recommendation to draw down Pool 5 near Minnieska has been endorsed by the River Resources Forum. A final decision has not yet been made on whether to draw the pool down 1.5 or two feet.

The River Resources Forum (RFF) is a consortium of state and federal agencies that make recommendations on navigation and habitat restoration to the Corps of Engineers. Both the Corps and the RFF support the drawdown as a means to restore lost vegetation to the pool, of which Weaver Bottoms is a prominent part.

"Temporary drawdowns are a proven means for exposing bottom substrates that are otherwise under water," Schlagenhaft stated. Exposing portions of a reservoir's bottom triggers germination of aquatic seeds for plants such as arrowhead, bulrush and cattail that have been laying dormant in the mud.

"These emergent plants are absolutely critical for good water quality and they also provide excellent food and protection for waterfowl and fish," Schlagenhaft explained. "Weaver Bottoms, for example, was once lush with aquatic vegetation and full of fish and waterfowl. Most of that vegetation, however, has been lost over the years and as a result the fish and waterfowl are no longer there, either." Schlagenhaft said a drawdown of Pool 8 in 2002 resulted in about 2,000 acres of mud flats being exposed. Those flats were subsequently colonized by annual and perennial vegetation and fish and waterfowl responded to it almost immediately."

Public support for both the Pool 8 drawdown and the proposed Pool 5 drawdown has been "great," Schlagenhaft stated. "Some people said they could remember what the habitat in these areas used to be like and how it was to watch it slowly deteriorate over the years. They excited about giving these areas new life."

For the past 70 years, water levels in the Mississippi River have been controlled by a series of dams designed to support commercial navigation. Reservoirs behind these dams (called pools) range from 10 to 40 miles long. By holding pool water at levels high enough to support navigation, aquatic vegetation effectively began to drown. Suffocating siltation coming into the river from various tributaries worsened the situation, creating nearly lifeless bodies of water.

In order to facilitate a drawdown, Schlagenhaft said, it was necessary to accommodate not only the commercial navigation industry but recreational boaters as well. "We needed to have a plan that would allow commercial navigation to proceed and also provide a reasonable level of recreational access while the drawdown was underway," Schlagenhaft stated.

The solution was to allow for a certain amount of "environmentally sound dredging" in the main channel and also at priority recreational sites prior to the drawdown.

The Corps of Engineers has budgeted $1 million for main channel dredging, which would cover the cost of a 1.5-foot drawdown. Another $230,000 would be needed for dredging under a 2-foot drawdown scenario. The Minnesota and Wisconsin DNRs, along with the U.S. Fish and Wildlife Service, is providing funding for recreational access dredging.

Depending upon the extent of the drawdown, between 900 and 1,500 acres of Pool 5 could be exposed, including some 400 acres within the Weaver Bottoms. River flows this spring and summer, however, will largely determine the success of any drawdown, according to Schlagenhaft.

"River flows need to be in the normal range for a successful drawdown," Schlagenhaft noted. "If it's either too high or too low it will prevent us from doing the drawdown."

The drawdown is tentatively slated to begin on June 13 and end in mid-September. Water levels will be lowered at a rate of 0.2 of a foot per day. A follow-up drawdown is also under consideration for the summer of 2006.

Public meetings will be held in May to provide more information about this year's planned drawdown. In the meantime, additional information can be obtained by contacting Schlagenhaft at 507-280-5058 or tim.schlagenhaft@dnr.state.mn.us.

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