The rivers flowing into Lake Erie carry phosphorus and other nutrients that can lead to harmful algal blooms in its western basin and hypoxic (low oxygen levels) conditions in its central basin. Despite nutrient management efforts, algal blooms and hypoxia that impact drinking water, tourism, swimming and fishing have become more extensive in recent years. In 2012, the US and Canada signed a revised Great Lakes Water Quality Agreement which, in 2016, led to the adoption of new phosphorus loading targets and the development of action plans to meet those targets. The plans were released in 2018.

About this project

The Detroit River provides approximately 80% of the flow and 25% of the phosphorus entering Lake Erie; however, the sources of this load have been somewhat uncertain. In 2016, the Erb Family Foundation provided support to a project team based at the University of Michigan to characterize sources and evaluate management options for the St. Clair-Detroit River System watershed (See study area map). The team developed four models to simulate the dynamics of this complex, binational watershed that includes extensive urban and agricultural environments as well as the large, shallow, productive Lake St. Clair, which receives and processes the loads upstream of the Detroit River. A diverse project advisory group provided feedback on the policy context, planned research approach, and resulting products.

Project period: January 2016 - December 2019 
Participants: List of advisory group members and research team 
Funding: This project was one of two funded by the Fred A. and Barbara M. Erb Family Foundation. To learn more about the other project, visit: the NEW-GI webpage.

Final report and report supplemental information

Project findings summarized in the final report provide a more complete understanding of the relative contributions of different sources of phosphorus within the St. Clair-Detroit River System watershed, including Lake Huron, point sources, combined sewer overflow events, and runoff from both agricultural and urban lands. 

• Executive summary
• Full report
• Report supplemental information. This includes a summary of advisory group meetings and consultations as well as additional information about data sources and methods for the modeling and analyses described in the report..
• Data summaries for CSO basins in metro Detroit

Project slides

As a PDF, these slide decks can be viewed online as a graphical way to review project findings. Power point versions are also available for those interested in incorporating project results into their own presentations. One note, we have included a lot of text explanation on each slide, some of which can be used as talking points and removed from the slides for a cleaner presentation.

Brief overview slide deck - PDF or PPT 
Detailed overview slide deck - PDF or PPT

Related resources

Here we list a few resources and projects related to one of the modeling tools used in this project, the Soil & Water Assessment Tool (SWAT).

Soil Water Assessment Tool (SWAT) FAQ 
How SWAT models phosphorus 
SWAT Infographic 
Informing Lake Erie Agriculture Nutrient Management via Scenario Evaluation

Journal articles from this project

Mass balance and Lake St. Clair modeling

• Bocaniov, S. and D. Scavia. 2018. Nutrient loss rates in relation to transport time scales in a large shallow lake (Lake St. Clair, USA - Canada): insights from a three-dimensional lake model. Water Resources Research 54 (6): 3825-3840.
• Bocaniov, S.A., P. Van Cappellen, D. Scavia. 2019. On the role of a large shallow lake (Lake St. Clair, USA-Canada) in modulating phosphorus loads to Lake Erie. Water Resources Research 55(12): 10548-10564. 
• Scavia, D., S. Bocaniov, A. Dagnew, C. Long, Y. Wang. 2019. St. Clair-Detroit River system: Phosphorus mass balance and implications for Lake Erie load reduction, monitoring, and climate change. Journal of Great Lakes Research 45(1): 40-49.
• Scavia, D, E.J. Anderson, A. Dove, B. Hill, C.M. Long, Y. Wang. 2020. Lake Huron’s Phosphorus Contributions to the St. Clair-Detroit River Great Lakes Connecting Channel. Environmental Science and Technology 54(9): 5550-5559.

Urban sources assessment and modeling

• Hu, Y., C. Long, Y. Wang, B. Kerkez, and D. Scavia. 2019. Urban Total Phosphorus Loads to the St. Clair Detroit River System. Journal of Great Lakes Research 45(6):1142-1149.
• Hu, Y., D. Scavia, and B. Kerkez. 2018. Are all data useful? Inferring causality to predict flows across sewer and drainage systems using Directed Information and Boosted Regression Trees. Water Research 145: 697-706.

Watershed modeling

• Dagnew, A., D. Scavia, Y. Wang, R. Muenich, C. Long, and M. Kalcic. 2019a. Modeling Flow, Nutrient and Sediment Delivery from a Large International Watershed using a Field-Scale SWAT model. Journal of the American Water Resources Association 55(5): 1288-1305.
• Dagnew, A., D. Scavia, Y. Wang, R. Muenich, and M. Kalcic. 2019b Modeling phosphorus reduction strategies from the international St. Clair-Detroit River system watershed. Journal of Great Lakes Research 45(4): 742-751. 
• Long, C.M. and R.L. Muenich, M.M. Kalcic, and D. Scavia. 2018. Use of manure nutrients from concentrated animal feeding operations. Journal of  Great Lakes. Research 44: 245-252.

Synthesis and engagement

• Goodspeed, R.,  A.Van Eyl, and L. Vaccaro. 2018. Analyzing stakeholder's perceptions of uncertainty to advance collaborative sustainability science: Case study of the watershed assessment of nutrient loads to the Detroit River project. Environmental Impact Assessment Review 72:145-156.
• Scavia, D., S. Bocaniov,  A. Dagnew, Y. Hu, B. Kerkez, C. Long, R. Muenich, J. Read, L. Vaccaro, Y. Wang. 2019. Detroit River Phosphorus Loads: Anatomy of a Binational Watershed. Journal of Great Lakes Research 45(6):1150-1161.

Project Contacts

Project lead: Jennifer Read, Water Center, phone: 734-769-8898; email: [email protected] 
Lead scientist: Don Scavia, School of Environment and Sustainability 
Urban modeling: Branko Kerkez, Civil and Environmental Engineering