Michigan’s new water-quality plan for Lake Erie adds focus on algae-generating invasive mussels
Under a new plan to reduce harmful algal blooms in Lake Erie, the state of Michigan is putting a greater emphasis on the fight against two of the freshwater system’s most destructive invasive species. The Department of Environmental Quality released its multipronged strategy in November.
The plan mostly focuses on policies that better control the amount of phosphorus entering Lake Erie: for example, stricter permitting requirements for municipal wastewater systems and preventing nutrient runoff from agricultural operations.
“My fear is that we’re going to control phosphorus, but then not see a difference in harmful algal blooms, which is really the ultimate goal,” says Bill Creal, chief of the DEQ’s water resources division.
That is why the DEQ’s strategy also targets zebra and quagga mussels — invasive species first discovered in the Great Lakes in the late 1980s (brought here via the ballast water of oceangoing ships). These mussels, Creal says, have changed the Lake Erie ecosystem and contributed to the rise in harmful algal blooms.
Michigan plans to map out how densely populated these mussels are in the lake and to explore the efficacy of a new biopesticide that targets them. In 2014, the U.S. Environmental Protection Agency approved the use of Zequanox in open waters. The same year, the Michigan DEQ launched a pilot study in which this biopesticide was applied in a part of Lake Erie.
The state will build on last year’s study, Creal says, while waiting on a new formulation of Zequanox that could make it more effective in controlling the population of zebra and quagga mussels.
These invasive species, along with climate change, have contributed to the rise of harmful algal blooms in Lake Erie, a 2014 report from the International Joint Commission concluded. But that same study urges Great Lakes policymakers to make reductions in phosphorus runoff their top priority.
In 2014, the city of Toledo’s supply of drinking water was temporarily shut off due to a harmful algal bloom. That incident helped lead to the signing of a collaborative agreement between Michigan, Ohio and Ontario to reduce the amount of phosphorus entering western Lake Erie by 40 percent over the next 10 years.
Michigan’s main source of phosphorus loadings into Lake Erie has been the Detroit Water and Sewerage Department, via discharges into the Detroit River. However, because of a more stringent state discharge permit and the installation of new technologies, Detroit Water and Sewerage has greatly reduced the amount of phosphorus being released into the Great Lakes basin in recent years.
As part of Michigan’s plan for further reducing phosphorus loads, Creal says, the DEQ will tighten permit limits for Wayne County’s wastewater discharges. There are not yet specifics on how to better control agricultural runoff. Instead, the DEQ plan calls for new water monitoring in the Maumee River basin (located in a rural part of Michigan) and to work with Ohio and Ontario on a multi-jurisdictional strategy for controlling nonpoint sources of pollution.
|Stateline Midwest: December 2015||2.03 MB|