But the average lifespan of a dam is about 50 years, and the structures are no longer fulfilling their original purpose, said Amy Childers, outreach specialist for the DNR’s river ecology unit. Many of Minnesota's dams were built a century or more ago to control lake levels or generate hydropower. “If the dam were to break, what happens and who gets flooded?” Aging liabilities "When you hold back a lot of water, there's that safety issue,” he said. And they have other drawbacks, including holding back sediment that builds up in lakes and reservoirs instead of naturally flowing downstream.ĭams also pose a risk to the public, Baird said. Often, those narrower stretches of river are also where dams were built, he said, “so a lot of habitats have been lost.”ĭams also pose a barrier to native freshwater mussels, whose life cycle depends on their larvae hitching a ride on fish. Many fish species use faster-moving water and rocky rapids to spawn and place their eggs, Baird said. ![]() “Now they have an opportunity to move farther upstream and find new habitats for spawning.” "They get to the dam, and they hit that and stop,” he said. Owen Baird, fisheries management specialist with the Minnesota Department of Natural Resources in Brainerd, helped with the project, which received a $2.2 million grant from the state’s Outdoor Heritage Fund.īaird said dams prevent fish, such as walleye, white suckers and redhorse suckers, from swimming upstream.
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