Application and validation of a GIS-based stream bank stability tool for the Great Lakes region

Abstract

W atershed sediment contributions are a continual source of pollution to the Great Lakes. Sediment from upstream sources may deliver contaminants such as polychlorinated biphenyls (PCBs) and excess nutrients such as phosphorus to the lakes. The excess nutrients often contribute to algal blooms and degradation of freshwater habitat. The sediment loading from agricultural watersheds is often aggravated by ditch maintenance activities. Many of the agricultural lands draining into the Great Lakes lie on lacustrine clay and till plains and consequently have very little relief, resulting in poor drainage. Tile drains and ditches are often constructed in these areas to accelerate drainage and facilitate utilization of land for agriculture. Ditch maintenance activities include removal of riparian vegetation and dredging to increase conveyance. Section 516(e) of the Water Resources Development Act of 1996 directed the US Army Corps of Engineers (USACE) to develop sediment transport models for major Great Lakes tributaries contributing sediment to federal navigation projects (harbors, channels, etc.) or Areas of Concern (AOCs). Under this legislation, the models are developed to assist watershed stakeholders with the development of watershed management approaches to soil conservation and sediment management to reduce sediment loads, dredging costs, and the need for other sediment-based remediation activities.