The rivers flowing into Lake Erie carry nutrients such as phosphorus that can lead to nuisance and 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 fishing, swimming, tourism and drinking water systems have become more extensive in recent years. The sources contributing to Detroit River’s nutrient loads are somewhat uncertain due to limited data and lack of attention to its watersheds, and this uncertainty has complicated efforts to develop a regional strategy for reducing nutrient inputs.
Through the 2012 Great Lakes Water Quality Agreement, the U.S. and Canadian governments are developing strategies and domestic action plans to reach specific water quality goals. Phosphorus inputs (loads) have been identified as a central driver for Lake Erie, but it is not clear which management techniques and locations should be targeted to most efficiently and effectively reduce inputs. For example, what level of emphasis should be placed on combined sewer overflow releases, run-off from agricultural lands, or point sources of nutrients?
This study modeled the nutrient dynamics in the watersheds that drain into the St. Clair and Detroit Rivers. This bi-national watershed includes the Clinton, Rouge, Sydenham and Thames Rivers, as well as Lake St Clair and inputs from the cities of Detroit, London and Windsor.
The research team has developed three unique models that can simulate the dynamics of this complex watershed that includes extensive urban and agricultural environments on both sides of the border as well as a large lake (Lake St. Clair) that receives and processes much of the loads upstream of the Detroit River. The three models being developed are:
- An urban model to characterize loads from the greater Detroit area;
- A regional watershed model for the entire study area using the Soil and Water Assessment Tool (SWAT); and
- A Lake St. Clair model to explore nutrient transport and retention in the lake.
The modeling approach was designed to characterize nutrient loads to the Detroit River and then compare the efficacy of different management options. The University of Michigan team conducting this effort has modeled other river systems connected to Lake Erie, including the Maumee, Huron, and Raisin river watersheds.
Input from Policy and Management Advisors
A project advisory group provided feedback on the policy context, planned research approach, and resulting products. The advisory group included representatives from federal, state, and provincial governments; non-profits; universities; and local organizations actively involved in watershed management, policy development or applied research. Through bi-annual meetings and ongoing communication, the advisory group will help ensure the research is scientifically credible and the results are relevant and usable for the Great Lakes policy and management community.
Funding: This project is supported by the Fred A. and Barbara M. Erb Family Foundation
Project Period : January 2016 – December 2019
Journal Articles from this Project
Mass balance and Lake St Clair modeling
- St. Clair - Detroit River System: Phosphorus mass balance and implications for Lake Erie load reduction, monitoring, and climate change (Journal of Great Lakes Research, 2018)
- On the role of a large shallow lake (Lake St. Clair, USA-Canada) in modulating phosphorus loads to Lake Erie (in Review, Download PDF)
- 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, 2018)
Urban source assessment and modeling
- Are all data useful? Inferring causality to predict flows across sewer and drainage systems using Directed Information and Boosted Regression Trees. (Water Research, 2018)
- Modeling Flow, Nutrient and Sediment Delivery from a Large International Watershed using a Field-Scale SWAT model (In Press, Download PDF)
- Modeling phosphorus reduction strategies from the international St. Clair-Detroit River system watershed (In Review, Download PDF)
- Use of manure nutrients from Concentrated Animal Feeding Operations. (Journal of Great Lakes. Research, 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, 2018)