Saginaw River (Michigan)

Project Status: modeling is complete

River Basin Characteristics
The Saginaw River is a tributary of the Saginaw Bay. The total river watershed area is 8,595 square miles, and is a flat plain consisting mostly of agricultural and forested land.

		Designated Great Lakes Area of Concern Federal dredging costs exceed $1 million per year Agricultural practices impact the sediment loading; large sediment load carried by Saginaw River Commonly occuring contaminants include metals, nutrients, petroleum hydrocarbons, PCBs, DDT and other persistent organic compounds Stormwater quality and bacteria contamination are also a concern

Modeling Approach
The primary objective of the Tributary Modeling project for the Saginaw River was to find an effective solution to help stem the heavy sediment load to the Saginaw Bay. During previous studies in 1999 and 2000, HEC-6 was used to model the Saginaw River (Baird 1999) and Mike 21 was used to model Saginaw Bay (Baird 2000). These studies indicated that most of the clay and silt from upstream passes through the federal channel and settles in Saginaw Bay, while most of the sand settles in the river over the entire length of the channel. Since sand is larger in particle size than silt or clay, sand is easier to trap as it is transported downstream. Thus, the placement of sediment traps in-stream was proposed to catch a considerable fraction of the transported sand within the Saginaw River. The purpose of this Tributary Modeling project was to provide a theoretical analysis of sediment dynamics to evaluate potential trap locations, sizes, and efficiencies as a potential mechanism for reducing dredging costs in the navigation channel. A previously developed HEC-6 model was used to verify the theoretical approach and sediment production models (using AGNPS) were developed to determine sediment loading within the river.

Conclusions drawn from the Tributary Modeling project show that the proposed sediment traps captured incoming sediment with varying degrees of success, depending on the trap dimensions and incoming grain sizes. The location of traps  showing the greatest success were situated in a river segment where there is a sediment deposition environment. Therefore, it has been shown that the developed theoretical analysis and HEC-6 modeling can be used for sediment trap design and assessment of trap efficiency.

Project Partners
Baird & Associates
Wade-Trim, Inc.
East Central Michigan Planning Development Region
Institute of Water Research at Michigan State University
U.S. Environmental Protection Agency

Use and Applications
Using the completed Tributary Model for the Saginaw River, the benefits of improved agricultural practices (contour farming, no-till plowing, etc.) can be examined with respect to sedimentation. The sediment transport model can also be used to provide information on other methods to reduce the costs of dredging in the navigation channel.

For more information—or to obtain digital data for advanced modeling purposes—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