12 years 4 months ago
21st Avenue West Remediation to Restoration Project: Biological Survey and Hydrodynamic Modeling Results
Host, George E; Reschke, Carol; Brady, Valerie; Breneman, Dan; Dumke, Josh; Niemi, Gerald J; Austin, Jay; James, Matthew; Johnson, Lucinda B
The lower 21 miles of the St. Louis River, the largest U.S. tributary to Lake Superior, form the 4856 ha St. Louis River estuary. Despite the effects of more than 100 years of industrialized and urban development as a major Great Lakes port, the estuary remains the most significant source of biological productivity for western Lake Superior, and provides important wetland, sand beach, forested, and aquatic habitat types for a wide variety of fish and wildlife communities.
The lower St. Louis River and surrounding watershed were designated an “Area of Concern” (AOC) under the Great Lakes Water Quality Agreement in 1989 because of the presence of chemical contaminants, poor water quality, reduced fish and wildlife populations, and habitat loss. Nine Beneficial Use Impairments (BUIs) have been identified in the AOC, including: Loss of Fish and Wildlife Habitat, Degraded Fish and Wildlife Populations, Degradation of Benthos, and Fish Tumors and Deformities. The St. Louis River Citizens Action Committee, now the St. Louis River Alliance (SLRA), was formed in 1996 to facilitate meeting the needs of the AOC. Following the recommendations of the St. Louis River AOC Stage II Remedial Action Plan, the SLRA completed the Lower St. Louis River Habitat Plan (Habitat Plan) in 2002 as “an estuary-wide guide for resource management and conservation that would lead to adequate representation, function, and protection of ecological systems in the St. Louis River, so as to sustain biological productivity, native biodiversity, and ecological integrity.” The SLRA also facilitated development of “Delisting Targets” for each BUI in the St. Louis River AOC in December 2008.
The Habitat Plan identified several sites within the AOC with significant habitat limitations. One of these sites, the “21st Avenue West Habitat Complex” (approximately 215 ha; Map 1), was identified by a focus group within the SLRA Habitat Workgroup as a priority for a “remediation-to-restoration” project. The focus group subsequently developed a general description of desired future ecological conditions at the 21st Avenue West Habitat Complex, hereafter referred to as the ‘Project Area’, including known present conditions and limiting factors of the area. In addition, the focus group recommended a process to develop specific plans and actions to achieve the desired outcomes at the site. As the next step toward the creation of an “Ecological Design” for the Project Area, Natural Resource Research Institute researchers, in cooperation with USFWS, USEPA, MPCA, MnDNR, and other partners, sampled the 21st Avenue West site in late summer of 2011 to establish baseline information on vegetation, sediment types, benthic macroinvertebrates, toxins and bird usage of the area. This work will inform development of an ecological design that will allow assessment of restoration scenarios in the Project Area. The project will build on the 40th Ave West Remediation to Restoration effort, which developed an aquatic vegetation model based on depth, energy environment (predicted from a fetch model), water clarity, and other environmental factors. The model allows the evaluation of restoration scenarios involving changes in bathymetry, remediation or enhancement of substrate, reduction in wave energy, and other strategies. In this report we also incorporate a hydrodynamic model of the estuary to inform the ecological design process. Relationships between vegetation and the macroinvertebrate and avian communities will provide information on the efficacy of these strategies in remediating and restoring overall habitat and biological productivity in the 21st Avenue West Habitat Complex. This project was funded under USFWS Cooperative Agreement Number F11AC00517; full details of the project can be found in Attachment 1 of that Agreement.