In 2019 the United States will celebrate the 20th anniversary of the modern dam removal movement that began with the Edwards Dam on the Kennebec River in Maine. Since that time over 1500 dams have been removed. While some of the more than 80,000 in the United States provide important water supply, flood control, hydropower, and recreational functions, most no longer serve the original purpose for which they were built and may no longer make sense. Practitioners and resource managers have demonstrated that removing dams and other instream barriers can be one of the fastest, most effective ways of permanently restoring the ecological function of rivers. Dam removal provides a variety of benefits, including restoration of more natural hydrologic and sediment transport regimes, reestablishment of lotic habitat, and reconnection of fragmented historic migratory corridors for movement of aquatic species.
Over the last 20 years a deliberate movement has advanced barrier removal to benefit fisheries, river habitat, and community safety. Community attitudes and scientific understanding surrounding dam removals have shifted. Reviewing patterns of dam removal, we have identified key lessons from the United States in order to increase the rate and quality of dam removal. Where we once worked opportunistically, we now focus on multiple dams within a watershed and begin to plan for larger, more controversial and impactful projects. Bringing thoughtful monitoring and science we are addressing regulatory concerns about long-term environmental impacts, allowing for better project design and implementation. Changes to key laws and policies are incentivizing removal for dam owners, and clarifying the regulatory process for applicants and engineers. Through strategic planning for removals, better project design, thoughtful monitoring, and key policy changes we present a path to a national movement to advance barrier removal and fish passage.