"Fish need to migrate up and down streams and sometimes use streams to migrate between wetlands or lakes as part of their life cycles," Nohner said. "Often they’re laying eggs upstream or in a wetland. Dams and other fish passage barriers block their ability to make that migration and thus make it difficult for them to successfully reproduce."

Nohner said while some fish are capable of jumping over small barriers, these barriers negatively impact some fish populations. 

"The DNR supports dam removal in many, almost all cases," he said. "We generally prefer to have dam removals as opposed to replacements or repairs because it re-establishes that connectivity and ability for fish to migrate up and down the river."

The difference in habitats upstream of a dam can be quite drastic from the ones downstream, senior academic specialist in the Department of Fisheries and Wildlife at Michigan State University Jo Latimore said. 

Latimore said fish populations aren’t the only thing affected by blockages, materials like sediment and silt can also become stuck and cause a build up. Latimore did her PhD dissertation on the Red Cedar River that flows through the campus at MSU and studied the differences between the upstream and downstream areas surrounding the weir. 

"One of the things that was really remarkable is the fact that above the weir, the water slows down because the dam slows the water flow down," Latimore said. "It tends to drop any sediment that it's carrying. The water doesn’t have the energy because it’s not moving very fast to carry the silt and sediment any longer."

Because the water cannot hold these materials anymore, the bottom of the river above the weir becomes muddy and muck-filled. However, the healthier habitat for aquatic animals includes gravel and rock. Latimore said the area above the weir was difficult to study because it was much deeper than below it and the sediment build-up made surveying hard. 

"Downstream of the dam, we found over 30 different species of fish living in the river, a pretty decent diversity of invertebrates and even native clams," Latimore said, adding that some of these species can be rare.

While it was difficult to understand the health above the weir, she assumes the slow flow and depth of the area makes for an undesirable and unhealthy habitat for the clams and vertebrates. Latimore said these blockages can affect the river in more areas than just where the structure is placed. 

"It can lead to more common flooding incidents because the water is slowed down and it backs up behind the dam during high water," she said. "I know we do see a lot of flooding on campus above the dam in the springtime."

However far the river is affected depends on the height and the landscape around the block, but its removal would certainly help the habitat, Latimore said. 

MSU’s Infrastructure Planning and Facilities is attempting to get one of the grants from the DNR, vice president for strategic Infrastructure, Planning and Facilities, Daniel Bollman said. 

Bollman said there are three main reasons to remove the weir at MSU: ecology, recreation and flood risk. He said he knows about the unhealthy habitat the weir creates for aquatic species and that canoeing and kayaking would be easier for those who use the river for restoration, but flooding has also increased over the past couple of years and the weir makes it more likely to happen. 

"Removing the weir would lower flood potential upstream so that would sort of preserve the habitat and the banks of the river and reduce the need for flood prevention methods," Bollman said. 

He said the weir was originally built in 1878 to create a reservoir to pump water for drinking and extinguishing fires. According to past research done by a biosystems engineering senior design team at MSU, the weir was also used for heating Williams Hall, a dormitory on campus. However, the weir is not used for any of these reasons anymore. 

Nohner said that there are several blockages in the state that presently don’t serve any purpose and are often posing risks to the communities they reside in. 

"Depending on the size of the dam, it could be a safety concern for health and human safety and they present a risk to property if they fail," he said. 

When looking through the lens of climate change, we see an increase in failures, Nohner said.

"We’re getting lots of big rainstorms punctuated by droughts, punctuated by bigger rainstorms, as we have a changing climate," he said. "Our dams are both in increasingly poorer shape and they're also experiencing higher peak flows that are testing them even more."

Nohner said the DNR is seeing more interest in removing dams than they have the resources for. The grants are competitive to receive and the agency looks at the removal from all angles to decide which ones are the most necessary. Whether MSU receives one of these grants or not remains to be seen.