Approximately 10,000 people evacuated as waters surge to record levels.
May 20 at 10:03 AM
Unprecedented flooding was ongoing Wednesday morning in Midland County, Mich., after a pair of dams collapsed following record rainfall. Thousands of residents have been told to evacuate as floodwaters gush into the communities along the Tittabawassee River, inundating homes and businesses and prompting an emergency declaration from Michigan Gov. Gretchen Whitmer (D). The flooding is threatening a major Dow Chemical plant that lies along the river.
[Chicago breaks May rainfall record for third year in a row as heavy rains soak Midwest]
The Edenville Dam was breached Tuesday evening after Midland received 4.7 inches of rain in a 48-hour period, following days of heavy rain across the state. The dam sits about 18 miles upstream of Midland, a city of more than 40,000.
That collapse sent floodwaters gushing into Sanford Lake, where a dam has powered the Boyce Hydroelectric Plant. The Sanford Dam succumbed shortly thereafter, the twin reservoirs of water left with no place to drain but into the city of Midland. A flash flood emergency is in effect for downstream areas of Sanford.
A view of the flooded area near the Sanford Dam on Tuesday. (Kaytie Boomer/MLive.com/The Bay City Times/AP)
According to the Associated Press, 10,000 residents have been evacuated.
The National Weather Service in Detroit issued a rare flash-flood emergency, the governor warning that downtown Midland could find itself under up to nine feet of water early Wednesday. News reports showed flooded Midland homes and businesses on Wednesday morning. The Weather Service bulletin described a “particularly dangerous situation” and “catastrophic” flood threat.
“Right now, the water is rising, and we won’t know the extent of it for maybe the next 12, 15 hours,” said Whitmer at a news conference Tuesday evening.
Scores of businesses have been shuttered in the fallout of the coronavirus pandemic, which has been particularly severe in Michigan, and are facing serious economic hardship.
“This is unlike anything we’ve ever seen before,” said Whitmer. “I feel like I’ve said that a lot over the last number of weeks, but this truly is a historic event that is playing out in the midst of another historic event.”
Major flooding begins when the Tittabawassee River hits 28 feet; flood stage is at 24 feet. As of 6:30 a.m. Wednesday, river gauges reported a level of 34.28 feet and rising. That’s enough to flood West Main Street from Main Street to Saginaw Road, with many homes experiencing overland flooding.
It supersedes the historic 33.9-foot flood stage measured on Sept. 13, 1986, which at the time was deemed a “once in 500 year flood.” National Weather Service hydrologists were forecasting a crest four feet higher early Wednesday. It remains unclear if that level will be reached.
A hydrograph showing the water level rising into unprecedented territory along the Tittabawassee River at Midland, Michigan on Wednesday, May 20. (NOAA/USGS)
Dow Chemical Co.’s Midland headquarters was evacuated, with only essential staff remaining on-site to monitor the situation. The facility is associated with a Superfund site due to excess dioxins, which are known to cause cancer, in the riverbed downstream of the plant.
“Dow has activated its local emergency operations center and is implementing its flood preparedness plan which includes the safe shutdown of operating units,” wrote the company on its Facebook page.
An aerial view of flooding as water overruns Sanford Dam in Michigan on May 19. (TC Vortex/Reuters)
Edenville dam’s previous owners were warned about safety issues
For years, the Federal Energy Regulatory Commission (FERC) has feared a failure at the Edenville Dam. According to The Detroit News, the dam has been of concern to federal overseers since at least 1999, when its owners were warned that more spillway capacity was needed to avoid a potential collapse.
The Edenville dam was constructed in 1924 and was on FERC’s list of “high hazard” dams, meaning that its failure could damage property and threaten lives.
Boyce Hydro LLC, which has owned three other dams along the Tittabawassee River, failed to meet FERC demands for years.
A January 17, 2019 FERC document notes “a history… of Boyce Hydro’s failure to comply with its license for the Edenville Project.”
In January of this year, a two-county authority purchased four dams and lakes from Boyce Hydro LLC, including Edenville and Sanford, for $9.4 million, and expects to spend $100 million to improve the dams. FERC had repeatedly faulted the previous owner for failing to maintain and improve spillways, which help direct excess water around the dam to relieve pressure on the structure.
FERC argued that the Edenville dam “could not handle 50 percent of a probable maximum flood for the region,” the paper reported, whereas in 2018, Boyce Hydro put the odds of a “probable maximum flood” event occurring during the next 5 to 10 years at “5 to 10 in one million.”
FERC revoked Boyce Hydro’s license on September 10, 2018, forcing the company to permanently disable its power generating capacity within the dam. The order, however, did not require Boyce to modify the dam’s structure. Boyce filed for a rehearing, which was denied on January 17, 2019.
Heavy rains are in line with recent trends
Heavy spring rains triggered the disaster. Much of the Midwest has borne the brunt of a wet weather pattern that’s left many areas with an extra 8 to 10 inches of rain when compared to average.
On Tuesday, Gladwin, Mich. picked up 2.53 inches of rain, while Central Michigan University in Mount Pleasant, about 25 miles west of the Edenville Dam, received 2.65 inches. Upwards of three inches fell upstream, pouring into a river that’s been already swollen in recent weeks.
Midland received 3.83 inches on Tuesday — its fourth-highest calendar-day rainfall total on record, and its wettest day since September 2015. Records date back to 1970.
During the past several decades, spring rainfall in Michigan has been on the increase, likely tied to warming temperatures and the air’s ability to hold additional moisture. Data point to a roughly 25 percent increase in March through May rainfall since 1970 in Midland, with similar trends observed areawide. Mean springtime precipitation in Gladwin has leapt from 7.1 inches in 1940 to nearly 9.3 inches nowadays. Spring temperatures have warmed a degree and a half there during that same time frame.
According to the U.S. government’s National Climate Assessment, the heaviest precipitation events in the Midwest have increased by 42 percent since 1958.
