Since the construction of U.S. Lock & Dam No. 3 near Red Wing, only the strongest fish have been able to force their way past the dam's gates.
A U.S. Army Corps of Engineers plan, however, proposes a first-of-its kind project for the upper Mississippi River: a passageway for other fish to swim upriver.
That includes several endangered fish species, said Dan Wilcox, a Corps fisheries biologist.
"We have to try and increase their abundance," he said Tuesday at a meeting in Red Wing. "Fish do have to move around in rivers. Dams limit that movement."
Corps officials say the plan --dubbed a "fishway"--would connect ecosystems on either side of the lock and dam, allowing fish to flourish in tributaries including the St. Croix, Kinnickinnic, Apple, Trimbelle, Rush and Chippewa rivers in Wisconsin.
One plan calls for a fishway looping around the dam that would allow for year-round passage. According to the Corps, the fishway would be a gradually sloping open channel with rough bottoms or a series of rock riffles and pools.
While Wilcox said the Corps has not recommended one specific passage design, a Corps document describes the "nature-like" fishway as "the most appropriate" for Lock & Dam No. 3.
The Corps selected the Red Wing-area lock and dam for the project since it is a "high priority location," Wilcox said. He said "high quality" tributaries north and south of the dam provide a unique opportunity to connect fish habitats.
Wisconsin Department of Natural Resources official Ron Benjamin said the result of an unabated passage would mean more resilient fish populations.
"It's very important that we try to do things to make our fish populations as robust as possible," Benjamin said.
Critics of the project worried whether a fish passage might drain the river's Pool 4-- stretching from Lock & Dam 3 to Lock & Dam No. 4 at Alma, Wis.--of its renowned walleye and sauger numbers.
A fishway is "not going harm the size of the fish population" among walleye and sauger in either Pool 3 or 4, Wilcox said.
Not surprisingly, anglers who call the northern Pool 3 their fishing grounds were supportive of the plan.
"I think it would be a great improvement for Pool 3," said Hastings resident Meredith Evans.
Benjamin said the hope would be for fishways to exist at every dam along the upper Mississippi one day. That desire caused some to wonder whether fishways would provide a springboard for Asian carp.
The proliferation of Asian carp--the problematic species notorious for leaping from the water around passing watercraft--will continue whether or not a fishway is installed, Wilcox said. The strong fish make their upriver invasion through open dam gates and locks, according to the Corps.
"A fishway is not going to speed the invasion of Asian carp," Wilcox said.
Wilcox said the $15 million project has the support of Wisconsin's Congressional delegation, though funding is no sure bet.
A fishway proposal was included in initial plans for the navigation safety and embankment project currently under way at Lock & Dam No. 3. Wilcox said Corps officials later realized they didn't have the authority or funding to include it in the $78.6 million project.
"So we dropped the fish passage feature from the study," he said.
Since then, the Corps has received funding authority through the Upper Mississippi environmental management program. Under that funding structure, the federal government would share costs with a partner--likely the state of Wisconsin.
But Rep. Ron Kind, D-Wis., said the navigation safety and embankment contract bid came in below projections, leaving what he said should be more than enough funding for a fishway.
"I'm having a hard time understanding the Corps' position on this," he said.
Corps project manager Terry Williams said the leftover money--about $19 million--goes toward other facets of the project, like labor costs, real estate acquisition and land mitigation.
"I think that's where the confusion is coming from," she said.
Wilcox said that if the project and funding is approved, workers could begin construction by 2013.
"We've got to get this done," Kind said.