St. Joseph River (Michigan, Indiana)

Watershed Characteristics

St. Joseph River, Niles Dam

The St. Joseph River is a tributary to Lake Michigan and discharges at St. Joseph, Michigan. The river basin contains eight sub-watersheds, including Prairie River, Coldwater River, Fawn River, Pigeon River, Little Elkhart River, Elkhart River, Dowagiac River, and Paw Paw River. It’s watershed drains approximately 4,685 square miles, including portions of counties within Indiana and Michigan.

Aerial photograph of an area predicted as a significant source of sediment

The St. Joseph River watershed is roughly 60 percent agricultural land use, 20 percent forested, and less than 10 percent urbanized. However, management practices within the agricultural industry have contributed to bank erosion and sedimentation issues within the watershed. Channelization, drainage of wetlands, and installation of artificial drainage systems have also altered stream temperature regimes and decreased flow stability. Most of the large cities located within the watershed are along the mainstem of the river and have significant effects on water quality. The lower and mouth segments of the St. Joseph River basin are also threatened by increased development pressure.

Modeling Approach

General outline of the St. Joseph River watershed modeling system

The purpose of this study was to develop a modeling tool that could be used by local stakeholders to minimize erosion and sediment delivered to the St. Joseph River and, subsequently, the St. Joseph Harbor.

RMA2-SED2D model domain, St. Joseph River

In this study, a model of the St. Joseph River watershed was created using the Soil and Water Assessment Tool (SWAT). Several scenarios that looked at the effects of dams, tillage practices, and the use of filter strips were developed and modeled. A comparison was also made with historical (pre-European development) conditions. Two-dimensional flow and sediment modeling was done for the inner harbor using RMA-2 and SED-2D to provide more detailed estimates of sediment movement and delivery to the near-shore zone of Lake Michigan.

Modeling was completed in July of 2005. A training workshop for state and local partners took place in August of 2005.

Use and Applications

SWAT Results for scenario 1 (conservation tillage)

The modeling project included the development of analysis tools that will enable the users to evaluate Best Management Practices (BMPs) to reduce sediment transport to the lower reaches, including the navigation channels and harbor. Several entities (watershed commissions, universities, etc.) have expressed interest in obtaining these models for use in future applications pertaining to the assessment of future land uses and the development of BMPs to address these issues.

Project Partners

For More Information:

Contact

James P. Selegean, P.E., Ph.D.
Great Lakes Hydraulics and Hydrology Office
U.S. Army Corps of Engineers – Detroit District
477 Michigan Avenue
Detroit, MI 48226
Office: (313) 226-6791
Fax: (313) 226-2398
James.P.Selegean@usace.army.mil