The U.S. Army Corps of Engineers is well-known for maintenance dredging within the Great Lakes to support navigability and commerce. Tributaries connected to the lakes contribute to increased sediment loadings causing channels and harbors to fill in. Therefore, dredging is typically done in federal channels and harbors to maintain authorized depths.
Primary sources for sediment supply in the Great Lakes Region can be linked to stream bank erosion and overland erosion within surrounding watersheds and tributaries. To reduce the need for maintenance dredging, the Corps of Engineers, Buffalo District has taken an active role in promoting soil conservation within the Great Lakes under the Great Lakes Tributary Modeling (GLTM) program.
The GLTM program was established under section 516(e) of the Water Resources Development Act of 1996. The authority permits the Corps of Engineers to develop sediment transport models to assist state and local agencies with planning and implementation measures for soil conservation and non-point source pollution prevention. Funding for the program is through annual Energy & Water appropriations.
Through the GLTM program, a suite of web-based tools were developed which estimate sediment loadings, erosion rates, non-point source pollutant loadings, and assess impacts of obstructions within a tributary within small agricultural or forested watersheds. The tools are free to use and range from simple to moderately sophisticated. The Buffalo District GLTM team has provided training to a large number of watershed groups and state and local agencies on how to use these web-based tools over the past 5 years.
“For stakeholders in smaller watersheds who perhaps lack access to consistent funding streams, learning how to use the free online tools allows them to perform their own analyses”, said Colleen O’Connell, Hydraulic Engineer.
The Buffalo District visited Fort Drum military base this past July in regard to assessment of small local watersheds that experience frequent flooding. This meeting led the Buffalo District Hydrology and Hydraulics Engineering Team to develop a scope of work for a future GLTM watershed assessment and technical assistance at Fort Drum. The majority of Fort Drum’s installation flows into Ogdensburg Harbor and the environmental personnel for the base were concerned with erosion around the installation.
In another example of reaching out to stakeholders, several Corps of Engineers, Buffalo District staff members provided web-based tools training to students at the University at Buffalo, Heidelberg College, and State University New York Potsdam.
“In addition to helping to minimize dredging, sediment transport modeling has supplemental benefits with respect to ecosystem restoration”, said Michael Voorhees, biologist and GLTM Program Manager for Buffalo, Pennsylvania and Ohio.
Field assessments are an essential part of evaluating a watershed, stream banks, channels, and overland areas. District biologists have the expertise to take stream bank soil samples and to determine the rate of erosion and potential for non-point source pollutant loading. Some factors they examine in determining erosion rates are the type of vegetation and soil composition along the bank of the water source and the presence of any natural or manmade obstructions such as a beaver dam or bridge. The robust web-based software allows the Corps of Engineers scientists to predict how much sediment would be reduced if strategic changes are made to how a tributary flows.
“When we discover high levels of phosphorous in a river bank, there is a greater likelihood of an algal bloom,” said Voorhees. Algal blooms are increasingly problematic in the Great Lakes watershed. Recently, the New York State Department of Environmental Conservation (DEC) reported findings of a bloom in Hoyt Lake in Delaware Park, within the City of Buffalo. Sometimes algal blooms are associated with high levels of toxins which make water unfit for recreational use.
The Corps of Engineers, Buffalo District is poised to assist state and local resource agencies in evaluating their watershed planning needs and alternatives for soil conservation and non-point source pollution prevention. If your organization would like to learn more, of get involved with the program contact: 716-879-4488 or Michael.E.Voorhees@usace.army.mil or visit our web page: http://www.lrb.usace.army.mil/Missions/Interagency-Support/Sediment/