Abstract:
A GIS tool for prioritizing removal of dams based on ecological and social metrics is presented. The Barrier Prioritization Tool uses a hierarchical decision making framework that entails identification of an objective, criteria of qualities that meet that objective, and measurable indicators to quantify if criteria is met. Here the primary objective is to identify the best dams to remove. Criteria include good habitat connectivity, good water quality connectivity and connectivity of stream miles while avoiding social conflict, improving flow downstream, and improving safety. Sensitivity of rankings to habitat indicators used indicates that indicators of habitat quality overlap. Following the construction of the Barrier Prioritization Tool, three prioritization scenarios are conducted for American Rivers; one prioritization includes social and safety criteria, another includes only ecological criteria, and the third is a prioritization specific to anadromous fish. All three of these prioritization scenarios identify dams within the top 20 ranked dams that are currently classified as pre-identified potential dam-removal projects, indicating that the tool is performing as intended. Dam removal has proven to be an effective mechanism of quickly restoring in-stream habitat for lotic species through connecting fragmented river networks and returning the system to a free flowing state. By aiding in the dam removal project identification process, this tool makes the restoration of streams through dam removal more efficient. In the future, this tool will be used by American Rivers and their colleagues to run other prioritizations of the tool while experimenting with different indicator and criteria weights in order to find more potential projects for removal.
