thumbnail

Sediment mobility and bed armoring in the St Clair River: insights from hydrodynamic modeling

Earth Surface Processes and Landforms

By:
, , , , , , , , , and
DOI: 10.1002/esp.3215

Links

Abstract

The lake levels in Lake Michigan-Huron have recently fallen to near historical lows, as has the elevation difference between Lake Michigan-Huron compared to Lake Erie. This decline in lake levels has the potential to cause detrimental impacts on the lake ecosystems, together with social and economic impacts on communities in the entire Great Lakes region. Results from past work suggest that morphological changes in the St Clair River, which is the only natural outlet for Lake Michigan-Huron, could be an appreciable factor in the recent trends of lake level decline. A key research question is whether bed erosion within the river has caused an increase in water conveyance, therefore, contributed to the falling lake level. In this paper, a numerical modeling approach with field data is used to investigate the possibility of sediment movement in the St Clair River and assess the likelihood of morphological change under the current flow regime. A two-dimensional numerical model was used to study flow structure, bed shear stress, and sediment mobility/armoring over a range of flow discharges. Boundary conditions for the numerical model were provided by detailed field measurements that included high-resolution bathymetry and three-dimensional flow velocities. The results indicate that, without considering other effects, under the current range of flow conditions, the shear stresses produced by the river flow are too low to transport most of the coarse bed sediment within the reach and are too low to cause substantial bed erosion or bed scour. However, the detailed maps of the bed show mobile bedforms in the upper St Clair River that are indicative of sediment transport. Relatively high shear stresses near a constriction at the upstream end of the river and at channel bends could cause local scour and deposition. Ship-induced propeller wake erosion also is a likely cause of sediment movement in the entire reach. Other factors that may promote sediment movement, such as ice cover and dredging in the lower river, require further investigation.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Sediment mobility and bed armoring in the St Clair River: insights from hydrodynamic modeling
Series title:
Earth Surface Processes and Landforms
DOI:
10.1002/esp.3215
Volume
37
Issue:
9
Year Published:
2012
Language:
English
Publisher:
Elsevier
Publisher location:
Amsterdam, Netherlands
Contributing office(s):
Office of Surface Water
Description:
14 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Earth Surface Processes and Landforms
First page:
957
Last page:
970
Country:
United States;Canada
Other Geospatial:
St. Clair River