In the spring, Tennyson wrote, a young man’s fancy lightly turns to thoughts of love. It would seem that goes for fish as well. Throughout the spring many are looking for good places to spawn, and they instinctively know the best places generally exist as far upstream into tributaries as they can go. But often they don’t get very far before literally running into a wall, such as a dam, a poorly designed or damaged culvert, or other barrier.
In Minnesota there is a light at the end of the fish barrier tunnel that’s powered by collaborative efforts of many partners. These include the Minnesota Pollution Control Agency, Department of Natural Resources, and other agencies, as well as local organizations and businesses with support from state and federal funding programs.
But before you can fix a problem, you need to find it and study it.
Barriers one of many conditions that stress fish
Every 10 years for a particular watershed, MPCA staff conduct on-the-ground and in-stream surveys to look for conditions that make life difficult for fish and aquatic insects. These potential “stressors” include too much sediment, low dissolved oxygen, lack of habitat, and barriers to fish passage.
For example, some of the best spawning habitat in the Red River basin is located in the Sand Hill River in what’s known as the beach ridge area of Minnesota. This area is a transition zone where thousands of years ago retreating ancient Lake Agassiz left behind gravelly stream beds and other features that fish find attractive for spawning. The problem was fish were having a hard time getting to these areas. Four concrete control structures installed in the 1950s did little to fix erosion and other problems caused by straightening and channeling the river. Instead, research confirms that these structures actually increase erosion, and keep fish from excellent spawning habitat upstream.
Over the past several years, local partners have replaced the dams with a series of rock arch rapids that help reduce erosion while also allowing fish to move 105 miles up and downstream from the main stem of the Red River to the Sand Hill River headwaters.
“The response was remarkable,” says Jamison Wendel, DNR Red River Basin fisheries expert. In the spring of 2018, following completion of the project, surveyors found six species of fish upstream of the former dams that were not found in previous studies: channel catfish, smallmouth bass, northern pike, silver redhorse, golden redhorse, and chestnut lamprey. Some were found spawning directly over the recently installed rapids.
Likewise, in 2005, a dam structure on the Red Lake River in Crookston was replaced with boulder rapids. Soon, anglers began catching catfish and goldeye where they rarely had before. One man reported catching a sauger (similar to a walleye) on the Red Lake River in Thief River Falls (some 40 miles from Crookston by car) for the first time in 45 years.
The Sand Hill project involved many local, state and federal organizations: the U.S. Army Corps of Engineers, MPCA, DNR, Board of Water and Soil Resources, and the local SWCD and watershed district. Three quarters of the $7.6 million project cost came from the Corps with 25% coming from Minnesota’s Outdoor Heritage and Clean Water fund programs.
Pollution-sensitive fish first to respond
Luther Adland, DNR fish passage expert, says it’s typical to find 43% fewer fish species upstream from complete fish barriers such as dams, and removing barriers can restore up to 68% of lost species. “It’s interesting to note that when you restore a fragmented system, the first species to return upstream are fish that are most sensitive to pollution and in need of protection,” he says. A few years after removal of the Minnesota Falls Dam on the Minnesota River near Granite Falls in 2013, more than 12 species had returned upstream, including those of special concern such as sturgeon and blue sucker, and threatened species such as paddlefish and black buffalo.
Culverts sometimes the culprit
The Lake Superior North Watershed in extreme northeastern Minnesota contains many pristine lakes and streams that support healthy populations of brook trout and other aquatic life that are sensitive to pollution, temperature, and habitat change. Even small changes in a relatively small area can affect their ability to reproduce and thrive.
The MPCA's stressor identification report for the watershed noted several areas where small projects could help trout. For example, one project will focus on fixing culverts under three roads that cross Fredenberg Creek, a tributary to the Two Island River 1.5 miles from Lake Superior. While these road crossings occur within several hundred feet of one another, “fragmentation along even short stretches of a trout stream can limit genetic diversity and access to needed habitat,” says Jeff Jasperson, a stressor identification expert with the MPCA office in Duluth.
The culverts are in poor condition and pose a barrier to native brook trout. In one case, trout have to find a way to swim under a culvert perched above the stream. “The only trout we see getting past some of these barriers are ones we refer to as ‘super trout,’” Jasperson says.
Two culverts will be fixed this summer and Jasperson hopes a third will be fixed after securing additional funding. Even this relatively small project requires a lot of coordination and negotiation with officials from the county, a railroad, and a mining company because the stream crosses several property lines.
“Without the monitoring work we are doing, a project like this one likely wouldn’t happen,” says Jasperson. “If they are not provided assistance and education on the issue, most landowners are not going to take the initiative on their own to replace stream crossings solely to benefit fish passage and stream habitat.”
Fish passage projects offer low-cost high returns
Jasperson said that while all stream restoration projects are important, those that focus on removing fish barriers can be especially so. “Reconnecting river systems is one of the lowest cost, highest return investments in the field of watershed restoration and protection.”
Some benefits are immediate. You see fish moving upstream and having access to better spawning habitat right away, while others are long term, such as ensuring genetic diversity and helping fish communities adapt to a changing climate.
So whether you’re fish or a fisherman in Minnesota, the focus on fish barrier modification projects means your chances of getting lucky this spring, and in the future, are better than ever.