By Kevin Elliott
A lake dam failure in northern Michigan in 2020 forced the evacuation of 10,000 people and over $200 million in damages. It also prompted Oakland County officials to take an inventory of some 91 dams under its control, plus a review of others not under county control. Here’s what they found.
The saying “out of sight, out of mind” tends to be the public’s prevailing thought on water infrastructure, such as water and sewer pipes, stormwater drainage and managing our many waterbodies — until it’s not.
“Water infrastructure is kind of an invisible thing, until there’s a problem,” said Oakland County Water Resources Commissioner Jim Nash. “We have pipes in the ground, and people don’t know they are there until we have a sink hole. A lot of water facilities just aren’t visible to people. If they don’t see it, they don’t know it’s there.”
When considering the issue of dam safety, ignoring problems long enough can result in catastrophe.
On May 19, 2020, the Edenville Dam failed in Midland, Michigan, after several days of historic rainfall, causing the eastern side of the dam to collapse and send billions of gallons of water downstream. The flood caused the Tittabawasee River to crest at over 35 feet, overflowing the Sanford Dam, 10 miles downstream. More than 10,000 people were evacuated from their homes, with the damage estimated to be over $200 million.
Investigators with the Federal Energy Regulatory Commission (FERC) reported in 2022 the cause of the failure was “foreseeable and preventable and resulted from multiple errors committed over nearly a century.” They found the dam was improperly designed and constructed, resulting in built-in flaws from the start. Ultimately, they said, loose sands inside the portion of the dam became saturated with water, leading to the liquefaction and sudden loss of strength. While the use of sand was a deviation from construction specifications, as well as steep slopes downstream that violated safety requirements, neither flaws were reported.
Built in 1924, the 54-foot Edenville Dam was constructed for hydroelectric power and flood control. At the time of its failure, the dam was owned by Boyce Hydro Power, which had its license to produce power terminated in 2018 by the FERC. In its termination, the regulatory commission cited that “the dam may not have the ability to pass enough water if a severe flood hits.” The Michigan Department of Environment, Great Lakes and Energy (EGLE) subsequently took oversight, noting the dam was sound. At the time, EGLE’s Dam Safety Unit had two people to cover the entire state.
“At the time Edenville happened, we had two people in the unit,” said Mitchell Thelen, an environmental engineer with EGLE.
Thelen, who is developing assessment systems and training in Lansing, said EGLE has since added more engineers to the unit and is improving systems to gather better information. He previously was responsible for inspections in southeast Michigan, including Oakland County.
“We now have seven people, and will soon have eight,” he said about staffing at the unit. “We have a lot going on. We are improving drastically how we do things, and the fruits of that are in the process and getting there. We are definitely going in the right direction.”
Thelen said the unit is tracking more inspections and updating information in the state’s database. The amount of information being put into the state’s database is improving, as well, with conditions of each component of the dam. Further, the state is tracking and updating hydraulic calculations based on rainfall data using a Probable Maximum Precipitation (PMP) study and evaluation tools to better predict impacts of rain events.
“Just with advancements in computer capabilities, we want to update our rainfall data and get better rainfall probabilities and rainfall data, and use that to assess the risk for each dam,” he said. “A lot of the watershed boundaries were computed with topology data, so we are updating those maps to help us quantify that so when there’s an emergency we know the velocity and depth of flow.”
Dam failures in Midland also sounded a wake-up call in Oakland County, where the county’s board of commissioners in June of 2020 requested the Oakland County Water Resources Commissioner’s (WRC) office compile regular reports of all dams in the county every two years. The WRC already provides reports of 35 dams it owns or operates, as required by state law. The resolution expands inspections to those outside of the WRC’s legal requirement.
“It’s been something that’s kind of been overlooked and certainly we need to know where we’re at with these situations,” former Oakland County Commissioner Eileen Kowall (R-White Lake), said in 2020 when introducing the resolution. “None of us wants to see remotely what happened in Midland to happen here.”
Nash said the report, which was issued in November of 2020, came on the heels of the failures in Midland.
“In 2020, after the dams broke in Midland, everyone wanted us to look at their dams because they didn’t want that happening here,” Nash said. “The commission asked us to look at the dams here. … Midland was a very large dam. We don’t have anything here that large that could fail in that way. Some of our lake level structures aren’t actual dams, they are more like pumps that pull water to control the lake levels.”
The Edenville Dam stood 54-feet tall, just 10 miles upstream from the Sanford Dam, which is 36-feet tall and stores about 15,000 acre feet. The dams are nearly the same age as Pontiac Lake Dam in White Lake, one of Oakland County’s largest dams, which stands 21 feet tall and stores some 7,400 acre feet.
There are 54 lakes in Oakland County with established lake levels that fall under the responsibility of the WRC. The department operates and maintains 36 lake level control structures, or dams, and eight lake level augmentation pumps. In some cases, levels for multiple lakes can be controlled with one pump or structure. The lakes the WRC has responsibility for include: Bunny Run; Bush; Cass; Cedar; Cedar Island; Cemetery & Dollar; Clear; Commerce Crystal; Dawson Mill Pond; Duck; Fox; Greens; Huff; Indianwood; Lakeville; Long (Commerce); Long (Oxford); Loon; Lotus; Louise; Lower Straits; Maceday: Mickelson; Middle Straits; Mohawk; Oakland; Orchard; Otter; Oxbow; Pontiac; Schoolhouse; Scott; Silver; Squaw; Sylvan; Tan; Tipsico; Lester; Union; Upper Silver; Upper Straits; Van Norman; Walled & Shawood; Watkins; Wa-me-gah; White; Williams; Woodhull; and Wormer. The WRC’s report also included data from 60 other dams regulated by other entities, as well as 46 unregulated dams.
Following direction from the Oakland County Board of Commissioners, the WRC issued its first report in November 2020. Ryan Woloszyk, a civil engineer with the WRC who heads up the dam inspection efforts, said an update was given to the board of commissioners, with the next report expected in 2025. The latest full version of the study available was released in 2020.
“After reviewing and compiling the available data, it can be said that the majority of dams in Oakland County are characterized as being in fair or better condition,” the WRC stated in its report. “Even among those that didn’t meet this threshold, there were not structures identified that appear to pose an immediate or significant threat to the environment or downstream property owners.”
Nash said the WRC report rates dams by their condition assessment and their hazard classification, with condition relating to the likeliness of a failure, and hazard classification the extent of damage expected. Condition assessments are assigned in accordance with four categories: Satisfactory, fair, poor, or unsatisfactory. An “unsatisfactory” assessment means the dam is considered unsafe; a poor assessment means remedial action is necessary; fair assessments include minor deficiencies; and satisfactory may require maintenance. Hazard classifications are based on the amount of damage and/or loss of life downstream in the event of a failure, ranging from significant to low hazard.
Dam failures likely to result in no loss of life or to have minor impacts are considered “low” hazard potential. Dam failures that could result in loss of life and significant impacts have “significant” hazard potential, and those expected to result in the worst damage and loss of life are rated “high” hazard potential.
“We rate two things: the likeliness and consequence of failure,” WRC Commissioner Nash said. “Small things are low-hazard, like they would cause some water to flow into a wooded area. Larger things, like knocking down houses, would be high hazard. That’s how we rate them.”
Overall, 71 of the 91 regulated dams in the county are classified as low-hazard potential, with 21 dams having significant or high hazard classifications.
Oakland County dams with high-hazard potential are: Clarkston Dam; Lake Louise Dam; Oxbow Dam; Pontiac Lake Dam; Wildwood Lake Dam; Lake Neva Dam; Heron Dam.
Oakland County dams with a significant hazard rating are: Clintonville; Loon Lake Dam; Ford Dam # 3; Holly Dam; Lake Orion Dam; Quarton Dam; Waterford Multi-Lakes Level Control; Winkler Pond Dam; Lake Sherwood Dam; Endicott Lake Dam; Davisburg Trout Pond; Wolverine Lake Dam; Wau-Me-Gah Lake Dam.
The WRC report found 17 of the county’s 21 “high” and “significant” hazard dams are in satisfactory condition, with Pontiac Lake Dam, Heron Lake Dam and Wolverine Lake Dam rated at “fair” conditions. One “high” hazard dam in Oakland County – Holly Dam – is rated in poor condition. Three “low hazard” dams – Vhay Lake Dam, Haven Hill Lake Dam and Erity Dam – were rated in poor condition. Overall, 48 of the 91 regulated dams were found to be in “satisfactory condition.”
When inspecting dams, engineers look at both obvious and subtle signs of deterioration, such as cracking or damaged concrete along spillways and abutments, EGLE’s Thelen said.
“For earthen dams, the main concern is seepage,” Thelen said. “As they get older, the structural stability goes down. We don’t like to see a lot of vegetation growing. Engineers may be looking for rodent burrows and wet spots on the downstream side of the embankment. All earthen dams have seepage, but when it changes or shifts it becomes a concern. Like, if we see a sinkhole, that’s a sign. With concrete, the main things we look for are big structural cracks, misalignment where concrete walls may slope if the foundation gives way and they start to tip. Concrete is slower to deteriorate, so you have more warning. Once an earthen dam starts failing, things can progress rapidly.
“Most of the problems, as was in Edenville, involve known issues. Usually the limiting factor is money to pay for it, and who is going to pay for it,” Thelen noted.
Owned and located in the Village of Holly, the Holly Dam was built in 1840, with the last inspection done in 2017. That report found the deterioration of the dam’s principal spillway could be a threat to the stability of the dam, with several cracks and spalling in the concrete. While not a direct threat to the operation or stability of the dam, the powerhouse was subject to vandalism. The dam has the lowest condition rating of “poor,” with a “high” hazard potential.
The Haven Hill Dam, in White Lake Township, is owned by the Michigan Department of Natural Resources (DNR), and was last inspected in 2015. The dam, which has noted deterioration along the concrete spillway and abutment walls, is in poor condition. It has a low hazard rating.
Vhay Lake Dam, in Bloomfield Hills, is owned by the Vhay Lake Property Owner’s Association. While the dam has a low hazard rating, the WRC noted the dam is in poor condition, with a 2017 report noting its spillway is in poor condition and capable of handling only half of the 100-year flow discharge for which it was designed. Damaged concrete and exposed rebar need repair, as do upstream wing walls and, with seepage noted downstream.
The Erirty Dam, in Beverly Hills, has east and west sections, with the eastern section owned by the Village of Beverly Hills. The owner of the western section is unknown, according to former Michigan Department of Environmental Quality records, which had inspected the dam between 1992 and 2012. The latest inspection report is from 2012, which noted then spillway was in poor condition, with trees growing along the abutments and concrete damage throughout.
The WRC’s report reviewed whether inspection reports were conducted for each dam, as well as whether Emergency Action Plans are in place in the case of failure, and when those plans were last updated if they do exist. All dams with “high” or “significant” hazard ratings are required to have an Emergency Action Plan in place, with all in compliance, according to the WRC’s findings.
Dams with no reports or past due reports and high or significant hazard ratings include: Clarkston Dam (high hazard), last inspected August, 3, 2011; Lake Orion Dam (significant hazard), last inspected July 29, 2016; Winkler Pond Dam (significant), last inspected Sept. 9, 2016; Endicott Lake Dam (significant) last inspected April 15, 2008.
The WRC found nine regulated dams with no inspections completed. As a courtesy, WRC staff performed visual inspections of all nine dams and found at least three to be in need of significant repairs. The Petrauskas Pond Dam was in poor condition with a failing outlet; the Second Lake Dam and Araho Dam were also in poor condition. The other six dams without inspection reports are Spring Lake Dam; Renchik Dam; Lower Hatchery Dams; Tull Lake Dam; Troy Lake Estates Dam; and Pebble Creek Detention Basin Dam;. While the WRC said all nine of the dams are rated low hazard, it’s important inspections are done and they be put on a regular inspection schedule.
Other dams have overdue inspection reports. For example, the Cranbrook Lake Dam, which is owned by Cranbrook Educational Community in Bloomfield Hills, houses a low hazard dam rated in fair condition; however, the findings are based on inspection documents last conducted in 1996. The dam, according to the inspection findings, lacked adequate spillway capacity to pass peak flood flows, and had a weakened embankment and spillway abutment walls from overgrown tree roots. Similar issues were noted in a 2000 inspection report of Pettibone Pond Dam in Milford, where the last inspection report was done in 2000.
Woloszyk, the engineer with the WRC, said some smaller, unregulated dams, are sometimes unnoticed by property owners until the WRC or another entity reaches out to them. In some cases, the WRC works to take ownership of the dam so repairs or removal may be done. The Clarkston Dam, he said, is being transferred to the WRC with the help of a state grant program.
“It was built by Henry Ford, and is quite old,” Woloszyk said. “It was intended to be part of a network of dams he was building to power his plants outside of urbanized areas in Detroit. The outlet runs under a building and a new outlet is required. It’s really common that someone buys a property with a dam on it. Another we are taking ownership is at Vhay Lake. The same thing happened: the new owners thought it was a water feature, and now they are responsible for this.”
As dams receive more attention, more resources have been made available in the form of grants. In May of 2023, EGLE announced $15.3 million in Dam Risk Reduction Grant Program funds, including $106,000 to the Village of Clarkston at the Clarkston Mill Pond Dam, and $530,000 to the Michigan Department of Natural Resources for work at the Heron Dam in Holly. The Clarkston project involves a study to replace a new water control structure. In Holly, the funds will help design and perform repairs to the outlet, inlet and gate structure to keep the dam safe and functioning. The project addresses seepage and embankment stability concerns that have been present for several years.
Despite the extra attention, work and funding being done to address dam safety in Michigan, the fruits of the state’s labor are still developing. While funding has increased, the state has long struggled with supplying adequate dollars for the program.
In 2009, the American Society of Civil Engineers (ASCE) published a Report Card on Infrastructure that included grades for each state’s dams. At the time, Michigan received a “D,” with the age of the state’s dams a major contributor. Of the state’s 2,600 dams, about two-thirds are older than their typical design life, with over 80 percent being over 50 years old. At the time, Michigan was still clawing its way out of recession and slashing budgets. Just four years earlier, former Governor Jennifer Granholm had proposed cutting $350,000 from the dam safety program, essentially ending it. The funding was later restored in the budget cycle, and the former DEQ reorganized as EGLE under the current governor.
The ASCE upgraded Michigan’s grade to a C- in 2018, and again in 2023 gave it the same C- grade.
“Michigan’s dam safety program budget was increased after dam failures at Edenville and Sanford in 2020, but new resources are needed to improve the overall condition of dams across the state,” the 2023 report stated. “The Michigan 21st Century Infrastructure Commission Report cited a need for $225 million over the next 20 years to manage aging dams.
EGLE maintains an online inventory of about 2,600 dams, with about two-thirds being older than 50 years. Michigan has 97 high-hazard potential dams regulated by the state.
“There have been programmatic improvements since the 2018 ASCE Michigan Report Card, but little improvement in the overall condition of dams,” the report stated. “Slow but steady rate of removal of dams since the 2018 report card has eliminated some high hazard dams and restored biodiversity benefits from water flow. The general condition of Michigan’s dams in the EGLE Dam Inventory remain relatively the same, warranting the same grade as the 2018 grade of C-.
“It is anticipated that the frequency of future inspections, monitoring/surveillance scope, capacity and permitting requirements will all be strengthened to reduce risk. However, the combined rate of dam removals/repairs (about 25 total per year) is not keeping pace with the aging nor are dams in elevated hazard state being quickly addressed.”