Flint, MI—Researchers from the University of Michigan-Flint are studying fish species’ movement along the Flint River as the remainder of Hamilton Dam is set to be removed. 

In May 2023, the Michigan Department of Natural Resources (DNR) announced a $60,800 grant to help fund UM-Flint’s research on the passage of fish at the site of the Hamilton Dam removal. 

Removing the Hamilton Dam in downtown Flint will reconnect 25 miles of the Flint River. Rock structures that create rapids as a habitat for fish will then be put in place along the river. 

But water moving through the rock structures, also known as riffles, may travel too quickly for fish to move upstream in spring, a time when the river sees the highest volume of water, according to Heather Dawson, professor of biology at UM-Flint.

“If we’re removing the dam [and] those velocities are too high, then we’re not opening up that 25 miles of river that we think we are to a lot of fish,” Dawson said. 

Students and researchers eat watermelon and hot dogs during a cookout Heather Dawson (right), a biology professor at the University of Michigan-Flint, hosted in honor of one of her graduate students, Chloe Summers, who will soon travel to Madagascar for a research fellowship during a fishing day at Hamilton Dam in downtown Flint, Mich. on Tuesday, May 16, 2023. (Michael Indriolo | Flint Beat)

To offer insights on whether the riffles would need to be adjusted to best help fish move upstream, Dawson’s team aims to study the movement of walleyes, white suckers, smallmouth bass and lake sturgeons before and after Hamilton Dam’s removal. Further, the team will investigate if the riffles would serve as spawning grounds for fish species. 

Bryan Miesen, a UM-Flint graduate student, said data gathered from the research will help determine how useful removing Hamilton Dam is in restoring the ecosystem. 

Getting involved in the research is personal for Miesen, whose connection with game species dates back to his childhood years when his late grandfather first taught him the ropes of fishing and hunting, he explained. 

“It means everything,” Miesen said. “This is really gonna be a jumpstart to my career to show that I am out here, I am willing to work and help better the environment, get more anglers involved, and I want to keep our natural resources around for generations to come.” 

Danielle Henzarek, a student earning her master’s degree in biology at the University of Michigan-Flint, measures the length of a carp during a fishing day at Hamilton Dam in downtown Flint, Mich. on Tuesday, May 16, 2023. (Michael Indriolo | Flint Beat)
Lauren Bishai, Danielle Henzarek and Bryan Miesen identify a Northern Hogsucker caught by Christopher Mayes during a fishing day at Hamilton Dam in downtown Flint, Mich. on Tuesday, May 16, 2023. (Michael Indriolo | Flint Beat)
Danielle Henzarek (left) and Bryan Miesen (right), both students earning their master’s degree in biology at the University of Michigan-Flint unhook a carp during a fishing day at Hamilton Dam in downtown Flint, Mich. on Tuesday, May 16, 2023. (Michael Indriolo | Flint Beat)
Arianna Elkins (center), a student earning her master’s degree in biology at the University of Michigan-Flint, shows the contents of a fish’s vomit to Heather Dawson (right), a biology professor at UM-Flint, during a fishing day at Hamilton Dam in downtown Flint, Mich. on Tuesday, May 16, 2023. The fish’s vomit contained the claw of a rusty crayfish, an invasive species in the Flint River, Elkins said. This was an interesting find, she said, because evidence of native fish eating invasive species is scant. (Michael Indriolo | Flint Beat)
Arianna Elkins, a student earning her master’s degree in biology at the University of Michigan-Flint, shows the contents of a fish’s vomit to Heather Dawson, a biology professor at UM-Flint, during a fishing day at Hamilton Dam in downtown Flint, Mich. on Tuesday, May 16, 2023. The fish’s vomit contained the claw of a rusty crayfish, an invasive species in the Flint River, Elkins said. This was an interesting find, she said, because evidence of native fish eating invasive species is scant. (Michael Indriolo | Flint Beat)

Removing the Hamilton Dam is part of the ongoing Flint River Restoration Project. The goal is to rejuvenate the stretch of the Flint river running through the city of Flint by restoring its ecosystem, upgrading parks and creating more water-based recreational opportunities. 

The dam is more than a century old, and its superstructure that was above water was already removed in 2018. What remains is a barrier known as the weir. Removing the weir will likely take place in the summer of 2025, according to Jason Kenyon of Wade Trim, the engineering firm that’s managing the Flint River Restoration Project. 

UM-Flint’s team will be tracking fish movement and placing egg beds to monitor fish spawning in 2024 and 2026. But they’ve already begun preliminary research with internal funding, piloting their methods ahead of next year.

Christopher Mayes, a wildlife biology student at the University of Michigan-Flint, carries a freshly caught gizzard shad during a fishing day at Hamilton Dam in downtown Flint, Mich. on Tuesday, May 16, 2023. (Michael Indriolo | Flint Beat)

Nicholas is Flint Beat’s public health and education reporter. He joins the team as he graduates from Santa Clara University, Calif. Nicholas has previously reported on dementia and brain health, as...