ANN ARBOR, MI – As 3,500 cubic feet of water per second passed through Ann Arbor’s four city-owned dams with the Huron River approaching record levels on May 19, Brian Steglitz insists there was no reason to be concerned.
Steglitz, manager of Ann Arbor’s Water Treatment Services, offered the assurance in context of May’s failure and breach of dams near Midland to illustrate the city’s dams are capable of handling serious flooding events.
Ann Arbor’s dams are are capable of releasing between 12,000 and 17,000 cubic feet of water per second, Steglitz said, noting that the record in Ann Arbor was 5,840 cubic feet per second in 1918.
“It would have to be a lot more water before we would be in a condition where we felt like we may not be able to pass the floodwaters coming down stream,” Steglitz said. “We were not even close to what we have the capability of passing during this type of event.”
The City of Ann Arbor has stayed on top of maintenance of its aging dams acquired from Detroit Edison in the 1960s after power generation was decommissioned. There are six dams in the city, including two private dams on the north end.
The dams are each at least 100 years old and, although listed in “fair” condition, have a “high hazard” potential, meaning a failure would be life-threatening for people living downstream, according to the U.S. Army Corps of Engineers. Overall, Washtenaw County’s 29 dams have an average age of 83 years, while the average age in the state is 74.
Dam locations are approximate. Click Legends tab to add dams with "significant' hazard ratings.
Keeping Ann Arbor’s dams safe means hundreds of thousands of dollars in annual maintenance and operation costs for the city, Steglitz said, along with capital investments, annual inspections and hiring independent, federally certified consultants every five years to complete a safety report, which was most recently done in 2018.
Costs can add up and begin to make less sense when considering the potential environmental and safety issues associated with dams, Huron River Watershed Council Executive Director Rebecca Esselman said.
Michigan’s high-hazard dams: ‘This is something we’re going to wrestle with’
“Dams in general are a safety hazard when they’re in place,” Esselman said. “A river is inherently a free-flowing system. If you put a barrier in there and you stop that flow, you’ve really compromised that natural system."
With scarce funding sources available to either repair or remove dams in the county, the watershed council has helped municipalities remove dams in recent decades, including currently helping the City of Ypsilanti explore removing Peninsular Dam.
Infrastructure investment
Washtenaw County dams are regulated by both the state and federal governments, which keep records of their conditions and rate their potential to harm the public should they fail.
The Federal Energy Regulatory Commission has authority over about 100 hydroelectric power dams in the state, including Barton and Superior dams in Ann Arbor.
An overhead view of Argo Dam in Ann Arbor Tuesday, Feb. 5, 2019. Jacob HamiltonJacob Hamilton
Others that serve recreational purposes like Argo and Geddes dams are regulated by the Michigan Department of Environment, Great Lakes and Energy.
Both require different types of safety and regulatory measures, Steglitz said, with one city staff member dedicated to operating and maintaining the dams.
Inspections consist of walking the dam’s earthen embankments to look for anomalies like rodent holes, soft spots and erosion and addressing any items that need repair, Steglitz said. Water levels are measured with piezometers, or wells located in the embankment, to indicate how water is flowing through it.
Inspections also include checking mechanical and hydraulic components of the hydroelectric generator for normal operation, as well as a visual inspection of dam gates and concrete.
“From a dam safety perspective, there are a lot of eyes that look at these things and the safety program is pretty stringent in terms of making sure that we’re doing all the right things and in the right frequency,” Steglitz said.
In the past two fiscal years, the city has spent $680,000 on operations and maintenance for Barton and Superior dams and another $310,000 on Argo and Geddes dams.
Additional individual projects also can prove costly, including the $1.1 million Ann Arbor spent to replace four corroded spillway gates at Geddes Dam, based on recommendations by the state of Michigan Dam Safety Unit after its 2016 safety inspection.
The city spent another $543,000 in February 2018 to hire Kiser Hydro LLC, for a 10-year inspection and "overhaul” at Barton Dam that includes detailed equipment inspection and turbine equipment rehabilitation and replacement of various mechanical components.
The cost of safety
After the most recent high-water event, Ypsilanti Mayor Beth Bashert said an inspection of the historic Peninsular Dam revealed no additional damage other than the maintenance it already needed.
What happened in Midland reminded Bashert of the urgency surrounding the pending removal of the dam, which is estimated to cost $2.7 million. Of importance, she said, is the fact the city has been unable to insure the dam due to uncertainty around when its last maintenance occurred.
The City of Ypsilanti is in the process of seeking funding for the removal of Peninsular Dam.Jacob Hamilton | The Ann Arbor News
“Our initial motivation was to return the river to its original, healthy state,” Bashert said. “As we went further and further into the liability and protecting residents, that became our primary concern. A dam failure with loss of life, leaving the city with millions in debt is unacceptable.”
Ypsilanti enlisted the Huron River Watershed Council to hire an engineering firm to conduct a feasibility study for removing the dam, restoring the river and reviving the adjacent Peninsular Park.
City Council also considered repairing the dam at an estimated cost of $800,000, but ultimately saw removal as a safer, more cost-effective option in the long run for the decommissioned dam, which previously provided hydroelectric power from the 1860s to the 1970s.
Ypsilanti initially approved $500,000 toward removing the dam in May 2019 with the understanding that the city apply for grants to complete the project.
Securing additional funding has been a challenge, however, with funding for a major Fisheries Habitat Grant Program the city applied for to the Department of Natural Resources put on hold by the state amid budget concerns.
Grant funding would complete the comprehensive design phase of the project, Watershed Council Planner Daniel Brown said – the first major step after completing a feasibility study.
Ypsilanti city council votes to remove Peninsular Dam
“Generally speaking, the intent of that proposal is to get the project to the point where it’s ready for deconstruction of the dam,” Brown said. “The actual deconstruction and lowering of the water level safely can be completely fairly quickly. It’s the planning, permitting and fundraising that takes years.”
In the early stages, it can be difficult for communities to build support for a removal project when grant funding rests on investing in feasibility and engineering studies that can prove costly, said Joe Nohner, who manages the Michigan Department of Natural Resources dam management grant program.
“You’re early on in the process, so it’s risky," Nohner said. "It’s less attractive to fund an engineering project than it is to fund the final dollars of a project to finish it off.”
Remove, repair or remain?
A dozen years after the City of Dexter removed Mill Pond Dam in favor of constructing Mill Creek Park, City Manager Courtney Nicholls said the decision has “worked out in everyone’s best interest.”
With the anticipated reconstruction of a bridge over Mill Creek, the watershed council created a task force of citizens and city officials to evaluate alternatives for the dam.
Crews from the ET MacKenzie Co. begin demolishing the Mill Pond Dam in Dexter under the Main Street bridge in 2008. A dozen years after the City of Dexter opted to remove the dam in favor of constructing Mill Creek Park in the area of its impoundment, City Manager Courtney Nicholls said the decision has “worked out in everyone’s best interest.”Lynn Monson | The Ann Arbor News
The Washtenaw County Road Commission secured funds to rebuild the bridge, but dam removal costs were not included, leaving Dexter officials to absorb them. The city was awarded a $450,000 Michigan Natural Resources Trust Fund grant supporting the recreational development of the area including fishing and observation areas, storm water management, wetland enhancement and boardwalks.
Restoring a free-flowing habitat along the river has aided in the development of the park and current $1 million extension of the Border-to-Border Trail along the Huron River, Nicholls said, revitalizing an area “that nobody had access to.”
“The whole area was revitalized by the removal of the dam,” Nicholls said. "I don’t think anybody would argue (against) that point.”
Concerns from the Michigan Department of Environmental Quality regarding Argo Dam in 2009 caused the City of Ann Arbor to undertake a $1.17 million project to address the stability of its earthen embankment that separates the headrace from the main river channel.
While environmental groups pushed to remove the dam, that option was met with significant opposition from the local rowing community, which still frequently uses Argo Pond.
Both Argo and Geddes dams are considered recreational dams, funded through the city’s parks millage, for providing kayaking and other water activities that are popular summer attractions. Superior and Barton dams, on the other hand, produce hydroelectric power capable of creating enough electricity to power 1,500 homes.
The functionality of Ann Arbor’s dams, Esselman said, provides ample reason to look elsewhere for dams that should be removed.
“(Dams) that are still used for hydropower or reservoirs that are active with recreation don’t need to be a priority (for removal),” Esselman said. "They have a contemporary use that’s active.”
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