Increased abundance of aquatic vegetation after a drawdown in Pool 5, Upper Mississippi River. - FWS photo by Gary Wege

Water level management on the Upper Mississippi River recently won a Seven Wonders of Engineering award from the Minnesota Society of Professional Engineers. 

The project involves environmental drawdowns in Pools 5 and 8 on the Upper Mississippi River National Wildlife and Fish Refuge.  These drawdowns were accomplished by the Water Level Management Task Force, an interagency partnership. 

The award will be presented, Feb. 23, to project sponsor the St. Paul District, U.S. Army Corps of Engineers, which manages water levels on the Upper Mississippi River for the federal 9-Foot Channel Project.
 
A pool-scale drawdown involves a seasonal decrease in water levels at the navigation dam to mimic the low-flow cycle in the upstream reservoir that no longer occurs naturally. 

Drawdowns expose sediments which dry and improve reproduction of aquatic vegetation. They are a low cost way to improve large areas of shallow aquatic habitat that support fish and wildlife on the Upper Mississippi River. 

In addition to improving aquatic vegetation, the project was also designed to maintain the federal 9-foot channel project for commercial navigation, minimize adverse effects on river recreation, and educate the public on the environmental benefits of drawdowns.