Ford Lake Dam was built in the 1930s to produce hydroelectricity for a nearby Ford plant. Ypsilanti Township now sells the electricity it produces to Detroit-Edison. Image: Elinor Epperson
By Elinor Epperson and Daniel Schoenherr
Like clockwork, Michigan’s Lake Ford and its downstream neighbor, Lake Belleville, turn bright green every summer due to harmful algae blooms.
The lakes, located near Ypsilanti in the southeastern part of the state, have struggled for decades with phosphorus pollution that encourages algae growth. The search for a solution is familiar to urban lake communities in the Great Lakes region.
But a hydroelectric dam that separates the two lakes can be used to stop algae blooms, an expert says.
“Maybe it’s not pristine anymore, but it’s certainly a lot better than it was,” said John Lehman, a professor of ecology and limnology at the University of Michigan. He found that damming Lake Ford can mix eutrophic water to prevent the oxygen depletion that causes algae blooms.
Preventing blooms before they start
The Environmental Protection Agency says neither lake is suitable for swimming and the fish in both are unsafe to eat. Excess phosphorus in both lakes keeps oxygen levels lower than needed to maintain the ecosystem.
Lehman recommended that the township periodically open the floodgates at the base of the dam. With enough water flowing through these gates, the lake water will mix and provide a constant dose of oxygen to the lake sediments, he said.
Lehman and Ypsilanti Township tried this method in 2008.
“We ended up being able to improve the condition of the lake in a really measurable way,” he said. But both lakes continue to bloom every year due to persistent high levels of phosphorus.
For decades, state and local agencies studying the lakes have argued that high phosphorus loads come from external sources, such as the upstream Ann Arbor wastewater treatment plant and surrounding phosphorus-fertilized lawns.
Lehman disagrees. He says it’s already trapped in sediment.
“Sometimes the lake exports more phosphorus than it absorbs,” he said.
The usual suspects
Lehman has been studying Ford Lake’s phosphorus levels for decades. He found they dropped after local and state regulations restricted phosphorus in lawn fertilizers.
These regulations were born from a growing awareness of the harms of excess phosphorus. Stormwater collects the phosphorus-rich fertilizer used on residential and commercial lawns and carries it to the nearest body of water. Excess phosphorus can lead to harmful algae blooms during the summer months.
Lake Belleville benefits from the changes to Ford Lake because much of its phosphorus comes from the other lake directly upstream, Lehman said.
Jim O’Neill, who lives on Lake Belleville, said he suspects other residents still use fertilizers containing phosphorus. The municipality has issued reminders regarding the fertilizer ban, but these regulations are difficult to enforce.
Jim and Melinda O’Neill’s property overlooks the east end of Lake Belleville. The O’Neills don’t boat or fish on the lake, but enjoy the view. Image: Elinor Epperson
“Sometimes you’ll see things going into the lake that shouldn’t be there,” O’Neill said. But Lehman maintains that the amount of phosphorus entering lakes is not the primary cause of harmful algal blooms.
What about wastewater?
The other external source of excess phosphorus is the Ann Arbor wastewater treatment plant. The state dictates the maximum amount of a contaminant that can enter a body of water without decreasing water quality.
The Michigan Department of Environment, Great Lakes and Energy reports that the plant’s phosphorus production has consistently fallen below these limits.
Lehman doubts that sewage overflows are a major factor in Ford Lake’s phosphorus. The largest spill in recent history at the Ann Arbor plant – a release of 13 million gallons of partially treated wastewater during the August 2003 blackout – did not cause a bloom algae.
“That was about 10 times the amount of phosphorus dumped (into the river)… in three days,” he said. That’s “more than you would normally get in an entire month.”
An annual nuisance
Despite these findings, phosphorus in Lakes Ford and Belleville exceeds state limits each year.
Lehman found that most of the phosphorus causing harmful algal blooms is released from sediment already present in the lake and not from external sources.
“It doesn’t matter how much comes down the river,” he said. “It’s just what’s happening in the internal dynamics.”
Midwestern soil is already rich in phosphorus, which is released from lake sediments when there is insufficient oxygen in the water, he said. Excess phosphorus fuels the growth of toxic cyanobacteria, which bloom to create a thin green coating on the water surface.
These algae blooms are a normal part of summer for residents of both lakes, said O’Neill’s wife, Melinda O’Neill.
“We see a lot of green (flowers)… it looks like (an) oil spill at the top,” she said.
Between 2022 and 2023, residents reported 23 different patches of green algae on Lakes Ford and Belleville to the Michigan Department of Health and Human Services. Tests found toxic byproducts of the bloom in only four locations. The presence of blue-green algae was checked in all locations except one.
A sign posted at Ford Lake Dam warns residents of the dangers of toxic algae blooms. Image: Elinor Epperson
But the O’Neills haven’t noticed much contamination in their nine years of living at Lake Belleville. Melinda said other residents complain about the lake’s water quality on Facebook, but the O’Neills only notice an occasional “fishy” smell during the summer. Otherwise, the family enjoys the water views and lakeside living.
“It’s like unwinding after a hard day at work,” Jim O’Neill said.
Changes on the horizon?
Ypsilanti Township continued to use Lehman’s recommended method for mixing Ford Lake water. But this comes at a cost.
Ford Lake Dam produces electricity that the township sells to Detroit Edison, the region’s power company. Opening the gates decreases the amount of electricity produced by the dam, resulting in a loss of revenue of $10,000 to $30,000 per year for the township.
Ann Arbor and Ypsilanti Township recently reached an agreement to update how they manage phosphorus from wastewater from the river, including Ford and Belleville lakes. Officials representing the two municipalities confirmed that the agreement was not yet finalized but was moving forward.
Robert Kellar, a spokesman for the Ann Arbor Public Utilities Administration, said the city hopes to address the “difference of opinion” about the source of the excess phosphorus.
Lehman has documented the continuing debate in his research papers over the years. Disagreements over lake management “suggest that acceptable recreational water quality may come with a quantifiable price,” Lehman wrote in 2014. Residents and local governments must decide what price they want to put for better water quality. water in their lakes.
