Western Lake Erie Basin Algal Bloom Study

WSP USA studied Harmful Algal Blooms in the Western Lake Erie Basin to help the U.S. Army Corps of Engineers determine if placement of dredged materials was exacerbating the problem.


  • U.S. Army Corps of Engineers, Buffalo District

Project Status

  • Complete

Developing a Strategy

Western Lake Erie Basin (WLEB) is experiencing Harmful Algal Blooms (HABs) with increasing frequency and intensity, causing regional ecological and human health concerns. Learning what contributed to the accelerating HAB occurrences was critical to developing a strategy to protect the Great Lakes, a resource that makes up 21 percent of the earth’s surface fresh water.

Dredging is necessary for harbor maintenance, and the federal standard in Toledo Harbor is open-lake placement of dredged materials. As the U.S. Army Corps of Engineers (USACE) significantly increased the quantity of dredged material moved from Toledo Harbor into Lake Erie, WLEB concurrently experienced an exceptionally large HAB event, causing public concern that the two events were interrelated.


Large-Scale Investigation

WSP directed a team on a large-scale investigation to scientifically evaluate whether open-lake placement had an impact on the HAB. We looked into potential phosphorus release from the dredged sediment, changes in turbidity, and whether vulnerable WLEB areas may be impacted from materials released during transport.

WSP implemented a rigorous six-month water quality and sediment plume sampling and monitoring program. We input the data into a calibrated model to evaluate current and future scenarios of open-lake placement of Toledo Harbor dredged material, and long-range transport of open-lake placed dredged material.


Setting the Standard

The comprehensive investigation demonstrated that Toledo Harbor maintenance dredging is not directly linked to HABs. The outcome was important because the quantity of annually dredged material makes alternative disposal options cost-prohibitive. The investigation sets the standard for future studies and questions pertaining to perceived connections among the placement of dredged material in open water and HABs.

The project received the American Council of Engineering Companies Platinum Award—its highest honor—in the area of Studies, Research and Consulting Engineering Services.