Dams disappear as DNR moves ahead with free-flowing rivers

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Rock arch rapids under a bridge at Dunton Locks County Park allow fish to move freely up and down the Pelican River. (DNR photo)

Aiming to return Minnesota’s river systems back to their original, untamed state, the DNR has for several years now been chipping away at older dams and other obstructions and replacing them with rock arch rapids -- or sometimes leaving the dams in place and building rock "ladders" to let fish move around them.

The idea is to help not just fish, but turtles, frogs, ducks, river otters and all manner of other critters, said Amy Childers, who works in the Minnesota Department of Natural Resource's River Ecology Unit.

Most recently modified were the outlet dams on Prairie and Lizzie Lakes, on the Pelican River chain between Dunvilla and Pelican Rapids, which saw work done over the winter and early spring.

The DNR works with whoever can get the job done -- lake improvement districts, counties, soil and water conservation districts, townships, cities, lake associations, private property owners -- and every project is different, and has different funding sources, said DNR assistant fisheries supervisor Howard Fullhart in Fergus Falls.

In the case of dam-modification projects on Fish, Lizzie and Prairie lakes, the Pelican Group of Lakes Improvement District “was the driving force on all three,” Fullhart said.


It started with Fish Lake. “They wanted to create a fish passage and rock arch rapids,” in place of the outlet dam there, he said.

The Pelican LID landed a grant from the state’s outdoor heritage fund, which drew some federal Fish & Wildlife Service dollars, and then it added some of its own money, Fullhart said.

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The Fish Lake outlet dam prior to the rock arch rapids project. (DNR photo)

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The Fish Lake outlet after the project was completed. (DNR photo)

When the Fish Lake project was done, there was money left over. People on Lizzie and Prairie lakes liked the look of the new rock rapids, wanted it done on their own lakes, and the Pelican LID helped make it happen, with more support from the outdoor heritage fund, Fullhart said.

On the Fish Lake project, Houston Engineering of Fargo did the survey work and concept design, let the bids and oversaw the project. Hough Inc. of Detroit Lakes won the contract and did the construction work.

Local contractors benefited and the DNR saw three dams modified on the Pelican River chain without having to be deeply involved, “which makes for faster projects, also,” Fullhart said.


DNR Fisheries oversees work on many of the smaller projects, when smaller, older dams are on DNR-owned land, Childers said.

What’s the point of it all?

Birds aren’t the only animals that migrate. When the rivers are open and free-flowing, then all sorts of animals -- fish, mammals, reptiles, amphibians, invertebrates -- use them as a path to migrate, according to written information from Childers.

Clean, free-flowing water, different water depths, and a good mix of streambeds -- including gravel, sand, boulders, and even woody debris -- are what make for diverse aquatic ecosystems, she added.

Let’s talk fish: They come in all forms and sizes, eat all sorts of different things, and have their own ideas about the best place to spawn or take cover.

Some fish, like redhorse suckers and darters, live their lives mostly in those fast flowing, shallowish, rocky areas called riffles.

Walleye, catfish, and rock bass, on the other hand, prefer deep, cool, slower moving pools, Childers said.

These areas also give fish vital shelter during the cold winter months, and refuge during the low-flow, dog days of summer and into autumn.

A lot of the smaller minnow species prefer the shallow, sandy, clearer areas to avoid predators.


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The Prairie Lake outlet dam in spring 2018. Few fish were able to power over the crest. The dam was enhanced with rock rapids earlier this year. (DNR photo)

And of course, fish of all shapes and sizes love the cover and feeding opportunities along banks with vegetation, downed trees, exposed roots or overhanging plants, she said.

As people are becoming more and more aware, everything in this world is connected: Childers says survival of river animals depends on the connectivity of where they live -- from backwaters to floodplains to lakes and wetlands.

As birds travel, so do fish and water critters, which migrate long and short distances, upstream and downstream, throughout the year, to breed, eat and recolonize.

Even those tasty walleyes, loved by fishermen, migrate out of the lakes every spring to spawn in the rocky riffles, or to escape low oxygen conditions in shallow lakes or wetlands during the winter.

Return of the lake sturgeon

Childers says some fish, like the mighty lake sturgeon (which can be more than six feet long and weigh almost 200 pounds) will migrate surprisingly long distances -- hundreds of miles.

Sturgeon spawn in the spring in steep riffles and rapids, and they travel hundreds of miles to search for, or return to, the fast flowing, rocky waters of their spawning areas.


Lake sturgeon were wiped out by the late 1800s in the entire Red River Basin -- doomed in part by dam construction and habitat degradation, Childers said.

Now they are back, after dams were removed on the Red River. Fingerlings have been stocked in Otter Tail Lake since 2002 and some are now 5 feet long.

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The Shoreham dam was replaced with this rock ramp and boulder weir. (DNR photo)

And lake sturgeon aren’t alone: Childers says other fish and aquatic species were eliminated by barriers as well. Stream surveys analyzed by the DNR River Ecology Unit in Fergus Falls showed that an average of 41% of the fish species downstream of dams were absent upstream of the barrier. When the dams were removed or modified, most of these fish species returned.

The rock arch rapids which replace dams are also safer for people to fish and boat around, Fullhart said. “Anytime you have a dam, you have a chance of someone drowning,” he said.

For all those reasons, the DNR has been working with local communities on its “Reconnect the Red” initiative by removing or modifying dams throughout the basin.

And yes, both the Pelican River and the Otter Tail River are part of the Red River Basin -- the Pelican joins the Otter Tail just west of Fergus Falls, and the Otter Tail then heads west to join the Bois de Sioux. Together they form the start of the Red River, which flows north to Lake Winnipeg.


So how is the initiative going?

‘Round these parts, more dam removal work has been done in the Detroit Lakes area than in the Fergus Falls area, at least for now: On the Otter Tail River, the dams that have been removed or modified into rock rapids include one at 335th Avenue in Rochert; the Lions Park dam in Frazee; and the Frazee mill dam.

On the Pelican River, the dams that have been removed or modified into rock rapids include a major project at Dunton Locks; the Shoreham dam; and of course the Fish Lake, Lake Lizzie and Prairie Lake dams.

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The Lake Lizzie outlet looking downstream from the culverts where the dam was replaced with a rapids. (DNR photo)

On the Pelican River, the major projects remaining in this area are bigger dams that completely block fish access at Bucks Mills and in Pelican Rapids. And changes are coming there as well.

The Pelican Rapids City Council has voted to proceed with modifications at the city dam site.

The Bucks Mills dam is on state-owned land, and “we’ll probably take on that project ourselves,” perhaps with a local partner, Fullhart said. It’s not yet clear what the project will entail. “We’re just scratching the surface with that one,” he said.”What can be done, what can’t be done -- there’s a whole lot of community outreach that needs to be done -- we can remove the dam, turn it into a rock rapids, or build a fishway around it.”

Moving southward, the dam at Dunvilla is a low dam that allows some fish access during high flows. That’s also true of the Otter Tail Lake outlet dam.


Further south, more work remains to be done on both rivers, since the privately-owned Elizabeth dam, the Phelps Mill dam and the Friberg dam completely block fish access, as do the Pisgah dam and the Central Wright dam near Fergus Falls.

On the plus side, the Diversion dam and the Steam Plant dam near Fergus Falls have both been modified to allow full fish access. The Diversion dam has a fish ladder.

Lakeshore owners are often concerned about water levels dropping if a dam is removed, but engineers using rock rapids “are able to maintain about the same flow as the dam,” Fullhart said.

Ultimately, opening back up a river into a free-flowing system could be a win-win situation: “People are impressed by how the projects look,” Fullhart said, and the rock rapids can create spawning areas that will lead to more natural reproduction of fish.

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The historic lock at County Locks Park that at one time allowed passenger steam boats to travel the Pelican River chain. It was replaced with rock rapids as part of a free-flowing rivers initiative in Minnesota. (DNR photo)

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