Nutrients (Annex 4)

Satellite image of an algal bloom on Lake Erie, taken on September 26, 2013. Credit: NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team at NASA GSFC.

Through the Nutrients Annex of the 2012 Great Lakes Water Quality Agreement, Canada and the United States have committed to:

“… contribute to the achievement of the General and Specific Objectives of this Agreement by coordinating binational actions to manage phosphorus concentrations and loadings, and other nutrients if warranted, in the Waters of the Great Lakes.”

Key Commitments

Canada and the United States agree to:

  • By 2016, develop binational substance objectives for phosphorus concentrations, loading targets, and loading allocations for Lake Erie;
  • By 2018, develop binational phosphorus reduction strategies and domestic action plans to meet the objectives for phosphorus concentrations and loading targets in Lake Erie;
  • Assess, develop, and implement programs to reduce phosphorus loadings from urban, rural, industrial and agricultural sources. This will include proven best management practices, along with new approaches and technologies;
  • Identify priority watersheds that contribute significantly to local algae development, and develop and implement management plans to achieve phosphorus load reduction targets and controls; and
  • Undertake and share research, monitoring and modeling necessary to establish, report on and assess the management of phosphorus and other nutrients and improve the understanding of relevant issues associated with nutrients and excessive algal blooms.

Under this Annex, Canada and the United States adopted Lake Ecosystem Objectives related to algae development for each Great Lake. To accomplish these objectives, the United States and Canada will establish binational phosphorus concentrations, loading targets and allocations while continuing to assess and implement programs and measures designed to manage excess phosphorus from point and non-point sources.

Progress will be made through the implementation of binational strategies and domestic action plans, with consultation and cooperation of partners. Aspects of this annex may be implemented and reported on through the Lakewide Management Annex.

For additional information on the focus of actions under this Annex, consult the current Priorities for Science and Action. The Priorities are based on an evaluation of the State of the Great Lakes, with input from the Great Lakes Executive Committee, participants at the Great Lakes Public Forum, and recommendations of the International Joint Commission.

Every six months, progress on this annex is reported at the Great Lakes Executive Committee meetings. Accomplishments will be described in the Progress Report of the Parties every three years, with the first expected in 2016.


This annex is implemented by a subcommittee co-led by Environment and Climate Change Canada and the United States Environmental Protection Agency. Organizations represented include:

  • Agriculture and Agri-food Canada
  • Chiefs of Ontario
  • Conservation Ontario
  • Great Lakes and St. Lawrence Cities Initiative
  • Indiana Department of Environmental Management
  • Indiana State Department of Agriculture
  • Michigan Department of Agriculture and Rural Development
  • Michigan Department of Environment, Great Lakes, and Energy
  • New York State Department of Environmental Conservation
  • National Oceanic and Atmospheric Administration
  • Ohio Department of Agriculture
  • Ohio Department of Natural Resources and Forestry
  • Ohio Environmental Protection Agency
  • Ontario Ministry of Agriculture, Food and Rural Affairs
  • Ontario Ministry of the Environment, Conservation and Parks
  • Ontario Ministry of Natural Resources and Forestry
  • Pennsylvania Department of Environmental Protection
  • U.S. Army Corps of Engineers
  • U.S. Department of Agriculture
  • U.S. Geological Survey
  • U.S. National Oceanic and Atmospheric Administration
  • Wisconsin Department of Natural Resources

As required, time-limited task teams can also be created to focus efforts on a priority issue or project, and will be disbanded when work is complete. Currently, the Nutrients Annex has task groups that focus on:

Task TeamPurpose
Lake Erie Adaptive ManagementDevelop and implement an adaptive management process to track and report on progress toward achieving Lake Ecosystem Objectives for Lake Erie.
Lake Ontario Objective and TargetsReview and if necessary, recommend revisions to nutrient objectives and targets needed to achieve Lake Ecosystem Objectives for Lake Ontario.