The effort to remove Ypsilanti’s Peninsular Paper Dam (Pen Dam) from the Huron River has made steady progress. The initial phase of planning for the removal has been completed, giving the project team a detailed understanding of what will be required to safely remove the dam and how to best restore this stretch of the Huron.
Pen Dam is a high hazard dam in poor condition. For decades, its removal has been a Michigan Department of Natural Resources (MDNR) river restoration priority. MDNR provided about $660,000 in grant awards to complete the past phase.

Pen Dam Ypsi plan
A “blended” alternative was ultimately selected for design: full dam removal of Pen Dam; full restoration of recovered lands in and adjacent to Pen Park on lands owned by the City of Ypsilanti; minimal alteration to recovered lands beyond a floodplain bench between the railroad bridge and Superior Road bridge; minimal alteration to recovered lands beyond the pilot channel upstream of the Superior Road bridge. Credit: Inter-fluve

Key Findings

To ensure a safe removal of the dam that protects people, wildlife, and other infrastructure, consulting engineers investigated the impoundment using several methods. They looked at how the flow of the river will change following dam removal, examined the underwater topography, called the bathymetry, and assessed nearby infrastructure.

Safely managing sediment for both people and wildlife is a central component of any dam removal project, so the engineers took samples of the sediment to understand what it’s made of and how much is there. Those measurements will inform the sediment management strategy during the actual removal. The samples showed that sediment quality was less contaminated than expected, with only one sample area out of thirty-three studied exceeding the direct contact criteria for humans. Sediment from that location will be addressed to avoid any risk of exposure. There is also less sediment than we thought during the early days of planning. The total volume of sediment in the impoundment is near the lower bound of our initial expectations, which is a favorable outcome.

Responding to concerns that sediment from the Pen Dam impoundment could negatively affect Ford Lake, we had the engineers take sediment samples from the upper reach of Ford Lake as well. In summary, the results showed Ford Lake is more contaminated than the Pen Dam impoundment. The goal is to reduce the movement of sediment from Pen Dam to Ford Lake for a variety of reasons, but if any sediment does move from the Pen Dam impoundment to Ford Lake during the removal, it will not make Ford Lake more contaminated.

Funding Needs

From all these investigations, the engineers developed a range of options for removing the dam and restoring the impoundment. The revised estimate for the cost of the dam removal and bridge fortifications was $2.96 million. After adjusting for inflation, that’s slightly less than the original $2.66 million estimate from the 2018 feasibility study. Final design, planning, and permitting costs came out to about $785,000.
Based on conversations with waterfront owners, community members, subject matter experts, and permitting agencies, the project team chose to expand the scope of restoration activities and active sediment management in the impoundment. That expansion increased the fundraising goal by about $10.3 million. The city’s financial commitment of $500,000 to the project has not changed, so the additional funds sought will be raised from external sources. Given the high visibility of the removal, the potential ecological value added, the resilience to climate change provided, and the benefits to community recreation, the project team felt it was worth the additional investment.

Funding Secured

Following two recent grant awards of $800,000 from the U.S. Fish and Wildlife Service and $1.6 million from the EGLE Dam Risk Reduction Grant Program, about $7 million has been secured for the remaining activities. In 2023, the City of Ypsilanti, with support from the Huron River Watershed Council (HRWC), received two significant awards for the removal of Pen Dam: The Michigan Department of Environment, Great Lakes, and Energy Dam Risk Reduction Program awarded approximately $3.8 million; the U.S Fish and Wildlife Service National Fish Passage Program awarded another $300,000. The Walters Family Foundation generously provided $100,000 in support to HRWC, which has been applied as a required match for other fundraising efforts. Including grants previously received and applied, the project has raised more than $6.1 million to date. The project team has several grant applications pending to raise the balance of funds needed. Gathering the finances for major infrastructure and environmental projects like this one takes time and support from many state and federal agencies. With the past planning work completed, we now have a better degree of understanding of the tasks, expenses, and benefits ahead.

Project Timeline

We expect the remaining pre-removal preparations to take about a year from when they begin, currently anticipated for June 2024 through June 2025. The construction phase, which includes removal of the dam spillway, dewatering the impoundment, and initial restoration activities, is expected to take a year. We currently anticipate that work will begin in the fall of 2025 and be completed in the fall of 2026. Ongoing restoration activities, such as environmental monitoring, erosion monitoring, and invasive species management, will continue for several years after that, with the most intense work in the first two years after dam removal.
This summer, HRWC will be leading mussel surveys to protect threatened or endangered mussel species. You may see professional divers and teams of volunteers closely examining the bottom of the river through Ypsilanti while looking for mussels.
The key milestone in this project is the dewatering of the impoundment. Any remaining balance of funds to complete dam removal and begin restoration efforts must be secured before dewatering of the impoundment can begin.

What Dam Removal Looks Like

Janeen McDermott, an engineer with GEI, previously described what a dam removal looks like, and Mario Sebastiani, the lead project engineer with AECOM, summarized the process during a recent presentation to city council. The gist is that the process is slow and deliberate, prioritizing safety at every step. The water level is lowered slowly. Residents downriver should see higher flows like what you’d see after a heavy rain. The total construction time in the former impoundment area following the point of dewatering is expected to be about one year.
Revegetation of the river corridor is expected to occur quickly. In similar dam removals, small, leafy vegetation like grasses, flowers, and shrubs have revegetated the area within a growing season. Fish often return almost immediately once construction concludes. Five to ten years after removal, it will likely be difficult for casual observers to telltell if a dam was ever there.

Acknowledgements

Senator Jeff Irwin, Representative Jimmie Wilson Jr., Congresswoman Debbie Dingell, and Commissioner Annie Somerville have all provided guidance and support for funding proposals. The Michigan Department of Natural Resources, the U.S. Fish and Wildlife Service, the Michigan Department of Environment, Great Lakes, and Energy, and the Washtenaw County Water Resources Commissioner’s Office have all provided critical expertise or funding at numerous stages. This project would not have advanced to where it is without the help of these leaders and agencies.
The project team, our professional engineering consultants, and the subject matter experts that advise us all routinely express excitement to see this major river restoration effort move forward. Many of them live along, work nearby, or otherwise have personal connections to this stretch of the Huron River. We consider it a once in a lifetime opportunity to improve community resilience and help create a sustainable future for Ypsilanti.

For more information about this project, please check out our Ypsi Pen Dam page here

Note: This post was updated on 5/6/2024 following the announcement of the EGLE Dam Risk Reduction Grant Program awards. The relevant dollar amounts from the original post have been updated to reflect the new information.