Nearly 2 million aging dams and millions more undersized road-stream crossings (e.g. culverts), present one of the most pressing infrastructure challenges for assuring public safety and ecosystem health in the U.S. In 2016, seventy-two dams were removed nationwide. While this is an exceptional achievement compared to years past and represents a significant accomplishment for specific states, local communities and rivers, it is clear that larger-scale solutions are needed to address the scope of this challenge regionally and nationally.
Through a series of regionally-focused studies, The Nature Conservancy, working with several partner agencies and organizations through the North Atlantic Aquatic Connectivity Collaborative (NAACC), has developed the most comprehensive database and assessment of stream barriers in the eastern U.S. This assessment is based on a suite of ecologically relevant metrics that were selected and weighted with input from an expert working group. The products include a consensus-based prioritization that articulates the relative potential for restoration across more than 200,000 stream barriers.
The resulting prioritization tools aim to support planners and managers in their efforts to target dam removals, fish passage improvements and other aquatic connectivity projects where they can have the most benefit for migratory fish or other species of interest. The tools are designed to enable resource managers and planners to create customized prioritizations based on user-defined objectives. The scope of the assessment can also be customized to provide a prioritization value at the regional scale or specific to a state or watershed.
To date, these support tools are being used as a foundation to inform a range of river restoration strategies including state and regional dam removal partnerships (e.g. Vermont’s ‘free VT rivers’, Chesapeake Bay Fish Passage Workgroup), state DOT road maintenance plans, and allocation of mitigation funding.
This discussion will provide an overview of the assessment methodology, results, contemporary applications, limitations and key opportunities.