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Harmful algal blooms in Lake Erie expected to be smaller this year, says NOAA

Harmful algal blooms (HABs) in western Lake Erie are expected to be smaller this summer than those in 2021, according to forecasting data from the National Oceanic and Atmospheric Administration (NOAA).

This is good news for communities that depend on Lake Erie for drinking water and recreation. It is also welcome news for scientists at the Michigan Department of Environment, Great Lakes, and Energy (EGLE) and their colleagues at the Michigan Department of Agriculture and Rural Development (MDARD), and Michigan Department of Natural Resources (DNR).  All three agencies are partners in a Lake Erie Domestic Action Plan (DAP) which created a road map to reduce phosphorus, a root cause of HABs, entering Lake Erie by 40 percent by 2025.

EGLE staffer conducts algae bloom sampling from Lake Erie shoreline near Stony Point.

 EGLE staffer conducts algae bloom sampling from Lake Eric shoreline near Stony Point.


Based on modeling, this year’s HAB is expected to measure at 3.5 on NOAA’s severity index compared to a 6 recorded last summer.  The index is based on the bloom’s biomass (the amount of cyanobacteria) measured during the peak 30 days of the bloom.  A measurement of 5 or higher is considered a severe bloom and extremely high blooms measuring 10 and 10.5 occurred in 2011 and 2015.

The Lake Erie HABs consist of cyanobacteria, or blue-green algae, which can produce microcystin, a known liver toxin that poses a threat to people and wildlife. These blooms can also close beaches and force local water supplies to increase chemical treatment of their source water.

In Lake Erie, several factors contribute to algal blooms.  Nutrient-rich water from wastewater treatment plants, farm fields and fertilized lawns, the effects of invasive species, and the warm, shallow waters of the lake are some of the known contributors, but there may be others that aren’t quite understood yet.

Michigan’s Lake Erie DAP calls for the state to implement an “active” adaptive management approach at two levels: the Michigan-specific level and the binational Lake Erie basin level. State agencies are following the adaptive management framework as defined by the U.S. Department of the Interior. This involves “…exploring alternative ways to meet management objectives, predicting the outcomes of alternatives based on the current state of knowledge, implementing one or more of these alternatives, monitoring to learn about the impacts of management actions, and then using the results to update knowledge and adjust management actions.”

Michigan’s plan is focused on:

  • Reducing phosphorus loads from four key wastewater treatment plants.
  • Reducing phosphorus loads from nonpoint, agriculture sources in the River Raisin Watershed, and Michigan’s portion of the Maumee River Watershed.
  • Forming collaborative partnerships to provide technical and financial assistance to farmers.
  • Reaching out to the public and farmers to promote understanding of good conservation practices.
  • Promoting wetland restoration and other land management initiatives.

In May 2015, nutrient reduction targets were established for the River Raisin Watershed and Michigan’s portion of the Maumee River Watershed. Focusing on these areas does not mean the state will not implement nutrient reduction practices in other areas draining to the Western Lake Erie Basin (WLEB).  However, the nutrients removed from other WLEB watersheds will be in addition to the nutrients removed in these priority watersheds.

EGLE’s Nonpoint Source (NPS) staff have also developed an agricultural inventory process focused at subwatershed scale, that includes watershed modeling, aerial photograph review, and field level verification of existing conservation practices. This type of subwatershed planning will help state agency partners and non-governmental conservation groups identify locations with the greatest potential to contribute sediment and nutrients to the surface waters in the WLEB. Implementation of agricultural best management practices on these high priority locations will reduce nutrients contributing to the algal blooms in western Lake Erie. 

From a monitoring perspective, EGLE is also teaming up with the Michigan Department of Health and Human Services (MDHHS) and 10 local health departments throughout the state to monitor cyanobacteria blooms. MDHHS and EGLE staff have provided these local health departments with training and microcystin test kits to collect samples for processing at the MDDHHS laboratory.

Efforts are also underway to reduce nutrient loads to Lake Erie and clean up the algae blooms at the federal level, within the state, and Canadian provincial jurisdictions by:

  • Determining uncertainties.
  • Defining the actions to take.
  • Implementing and then evaluating the results of those actions.

In addition to the local, state, federal, and even international focus on reducing HABs in Lake Erie, EGLE also has recommendations on how homeowners and farming families can do their part to reduce nutrient loading in our watersheds:

  • Don’t dump grass clippings or other landscaping debris into any water body.
  • Never throw anything into a storm drain.
  • Service your septic system regularly - get SepticSmart.
  • Dispose of pet waste in the trash or your toilet.
  • Volunteer with a local conservation group or watershed council.
  • Consider non-toxic fertilizers, herbicides, and pesticides alternatives.
  • Voluntarily prevent or minimize agricultural pollution risks with help from the Michigan Agriculture Environmental Assurance Program (MAEAP).
  • Request a confidential farm visit by MAEAP technician.
  • Reference the EGLE Nonpoint Source Program’s Best Management Practices Manual.

And finally -- always report suspicious-looking algae to EGLE by calling the Environmental Assistance Center at 1-800-662-9278 or sending an e-mail to