Great Lakes Moment: Beavers come knocking at the Detroit River’s former Black Lagoon

Great Lakes Moment is a monthly column written by Great Lakes Now Contributor John Hartig. Publishing the author’s views and assertions does not represent endorsement by Great Lakes Now or Detroit Public Television.

As recently as the 1980s, a small backwater on the Trenton Channel of the Detroit River in Trenton, Michigan, was so polluted and toxic that scientists named it the Black Lagoon.

Yes, there actually was a Black Lagoon.

It was cleaned up in the early 2000s, and in January 2021 Katie Mans of Trenton discovered evidence of downed trees recently cut by beaver. Few ever thought this was possible and everyone has been surprised.

The Detroit River has a long history of industrial and municipal pollution, dating back to the early 1900s. In 1984 and 1985, the United States and Canada undertook a major research study that assessed environmental quality of the Detroit, St. Marys and St. Clair rivers, and Lake St. Clair; identified pollution hotspots and sources of pollution; and recommended cleanup actions.

During that 1984-85 Upper Great Lakes Connecting Channels Study, scientists from the former U.S. Environmental Protection Agency’s Large Lakes Research Station in Grosse Ile, Michigan, sampled sediment from this small backwater embayment on the Trenton Channel. The first thing they noticed was an acrid smell from volatile organic compounds typically found in oil, like benzene, toluene and xylene, that are known to irritate the eyes, nose, throat and skin. As they brought the sediment samples aboard their boat, they quickly saw with their own eyes the oil and grease. From that point on this backwater embayment became known as the Black Lagoon. Other contaminants found in Black Lagoon sediment included mercury, lead, zinc and polychlorinated biphenyls, or PCBs.

These scientists discovered that oil and grease that had been indiscriminately discharged into the Detroit River during the 1940s-70s had flowed downstream and entered the Black Lagoon.

In this backwater embayment, water velocities slow down and contaminants settle out in sediment. Scientists refer to these areas as depositional areas because contaminants and sediment are deposited and accumulate over time. The 1984-1985 study recommended that sediment from the Black Lagoon and other contaminated areas be remediated to help eliminate harmful exposure and biological impacts.

The research performed in 1984-1985 laid the scientific foundation for the Detroit River Remedial Action Plan that identified the Black Lagoon as a contaminated sediment hotspot that required remediation to eliminate impacts on fish and invertebrates, and health advisories on human consumption of fish. With no viable “potentially responsible parties” and limited governmental funding, no real progress was made for ten years. Then in 1998, the Detroit River was identified as one of 14 American Heritage Rivers in the United States and the cleanup of the Black Lagoon was championed as one of its six priorities.

In 2004, the Great Lakes Legacy Act was enacted that provides funding for cleaning up contaminated sediments in Great Lakes pollution “hotspots,” or what governments call Areas of Concern. The Greater Detroit American Heritage River Initiative and other local partners pounced on the opportunity to get 65% of the cost from the federal government. Michigan was fortunate at that time to have the Clean Michigan Initiative that could be used to make the required 35% match on federal dollars. With the solid scientific foundation of problem identification, strong community support through the city of Trenton, the Greater Detroit American Heritage River Initiative and the Detroit River RAP, and available federal and state funding, sediment remediation of Black Lagoon became a reality.

John Hartig showing his three granddaughters a tree felled by a beaver at Ellias Cove in Trenton, Mich., January 2021. (Photo Credit: Danielle Kerns)

In 2004 and 2005, the U.S. EPA and Michigan Department of Environmental Quality removed 115,000 cubic yards of sediment from Black Lagoon and disposed it in a special containment cell at the Pointe Mouillee Confined Disposal Facility in western Lake Erie. In total, $9.3 million was provided through the Great Lakes Legacy Act and the Clean Michigan Initiative. At that time, it was the first fully funded sediment remediation project in the Great Lakes under the Great Lakes Legacy Act. Following sediment remediation in Black Lagoon, over $120,000 was secured by the Greater Detroit American Heritage River Initiative for restoring shoreline habitat in 2006.

In 2007, a major public celebration was held at Black Lagoon celebrating the sediment remediation and shoreline habitat restoration. Community and business leaders and school children attended. At the celebration, the Black Lagoon was renamed Ellias Cove in honor of the family who donated the adjacent land to Trenton that became Meyer Ellias Park.

All was quiet at Ellias Cove for over a decade, except for periodic anglers who stopped in their boats to fish in this restored backwater embayment and picnickers in the park. Then, much to the surprise of Trenton residents, Ellias Cove got a visitor – a beaver.

It had been over 100 years since beavers had been at Ellias Cove. During the 1940s-70s, millions of gallons of oil were being discharged to the river each year. To put this into perspective, it only takes one gallon of oil to pollute a million gallons of water. The situation was so bad that in 1960 and 1967 oil pollution caused the death of 12,000 and 5,400 waterfowl respectively. Beavers could not have survived during these four decades because oiled fur on beavers becomes matted and they lose their ability to trap air and water to maintain body temperature. The result is death.

Beavers first returned to the Detroit River in 2008 at DTE Energy’s Conner Creek Power Plant. Prior to that the last time beavers were reported in the Detroit River was 1877. The fur trade decimated beavers during the 1800s and early 1900s. Then decades-long oil pollution prevented the return of any beaver.

Today, they are regularly seen at Bayview Yacht Club and Conner Creek Power Plant on the upper Detroit River, in the canals and around Detroit’s Belle Isle, in the canals of Greyhaven Island in the Jefferson Chalmers neighborhood of Detroit, in the Rouge River near University of Michigan-Dearborn, around Grosse Ile on the lower Detroit River, and now in Ellias Cove in Trenton.

Few people thought that the return of beavers to Ellias Cove would ever be possible. What a success story – from the infamous Black Lagoon to welcoming back beaver after over a 100-year absence!

John Hartig is a board member at the Detroit Riverfront Conservancy. He serves as the Great Lakes Science-Policy Advisor for the International Association for Great Lakes Research and has written numerous books and publications on the environment and the Great Lakes. Hartig also helped create the Detroit River International Wildlife Refuge, where he worked as the refuge manager until his retirement.

Correction: 5/5/22 The name of a park was corrected.

Read more Great Lakes Moments on Great Lakes Now:

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Great Lakes Moment: A new vision for the former McLouth Steel site in Trenton

Great Lakes Moment: Sacred land of the Wyandot of Anderdon Nation

Great Lakes Moment: Detroit River and western Lake Erie get a checkup

Roller Coaster: Michigan’s long history with environmental contamination

Featured image: Oil being discharged from the former McLouth Steel Company, 1960. (Photo Credit: City of Trenton)