For those who took the time to check it out, a glimpse of a less-engineered Mississippi River was available in Minneapolis last week, when the U.S. Army Corps of Engineers lowered water levels below St. Anthony Falls. People frolicked on the river floor, which was visible under the Stone Arch Bridge, and enjoyed a much closer experience to river wildlife.
The slow drawdown was by 12 feet, beginning Saturday and completed Tuesday, and done so that the Army Corps of Engineers could inspect the upper and lower locks and dams at St. Anthony Falls. The river was then allowed to rise again after the inspection finished Thursday.
Only about a half-mile patch of the river was lowered, a single pool between the upper and lower St. Anthony locks. But it was enough of a vision of a wilder Mississippi River to spark curiosity. And an obvious question:
Why can’t the river be like this all the time?
The short answer is: It’s complicated.
It turns out that there are a lot of interests at play affecting water level management. “There are always conflicting desires for the use of the water,” said Doug Snyder, executive director of the Mississippi Watershed Management Organization, the joint-powers local government unit representing Twin Cities communities along the Mississippi River.
The lock and dam system was originally built to raise water levels in order to allow commercial navigation as well as provide a source of power generation and water supply. But as Snyder noted, the water levels are also kept up in places for recreational purposes.
One of those many interests bowed out in 2014, when the Mississippi River was closed to commercial navigation above St. Anthony Falls because invasive carp were making their way upstream. The locks and dams along the Mississippi are maintained by the Army Corps of Engineers and the Coast Guard to insure large barges can navigate the river.
Though commercial navigation is no longer allowed on the Upper Mississippi, other travel is still permitted, and the river also has sections that are authorized for power generation. The lower water level would prohibit both activities, said George Stringham with the U.S. Army Corps of Engineers’ St. Paul district. Congress would have to sign off on any plan to permanently alter water levels.
Keeping water levels higher also helps Minneapolis stock its water supply, said Whitney Clark, executive director of nonprofit Friends of the Mississippi River. Damming water in certain spots in Minneapolis also helps with flood management downstream. There is a natural fluctuation of water levels to consider, he added, like heavy snow years.
Yet Clark feels management of the locks and dams system should include more drawdowns, ones that are much larger and longer than what took place last week. “I’ve found the Army Corps of Engineers to be responsive to complaints from people like me thinking about the ecology of the river,” said Clark.
Ever since commercial navigation has been halted, Friends of the Mississippi River and the Mississippi Watershed Management Organization have endeavored to track the health of flora and fauna in the watershed. Clark says the lower water levels allow more land along the river to get sunlight, while seeds are able to take root and grow as water levels naturally rise. That in turn stabilizes bottom sediments which keeps water cleaner and clearer.
Aside from lowering water levels, another environmentally friendly tack would be to strategically deploy the locks and dams system so that water movement more closely mimics the natural flow of the Mississippi River — higher in spring from melted snow, lower in late summer — to help maximize plant and wildlife growth along the river.
To Snyder, the best way to come up with a plan for managing the river, one that comes close to properly balancing human interest with ecological needs, is to establish a body formed to bring all interested parties together and endowed with the authority to make certain decisions.
As Snyder likes to say, quoting an old adage, “Whiskey is for drinking, water is for fighting over.”