Fish Passage Outcome:Factors Influencing Progress

Obtaining permission from dam owners to remove their dams has proven difficult. Many private dam owners have chosen to keep their dams in place. While existing fish passage laws require landowners to provide fish passage or install fish ladders at dams and other stream blockages, legal action against all noncompliant dams would be costly and time-consuming. Landowner engagement around the benefits dam removals can provide could garner more support from this critical audience.

To support dam removals, local policymakers must understand the ancillary benefits dam removals can provide. In addition to restoring habitat to certain fish species, dam removals can reduce liability for dam owners (as many dams are considered attractive nuisances whose removal benefits public safety). Dam removal can also reduce the flooding of roads and bridges and improve public access to rivers and streams.

Our ability to open stream miles and restore fish passage is limited by a lack of financial resources. The average cost of removing a stream blockage is over $200,000, which means the Chesapeake Bay Program’s Fish Passage Workgroup would need more than $20 million in implementation funds to achieve its goal. Prioritizing lower-cost culvert replacements and targeting high-priority dam removals could ensure the strategic investment of public funds.

Populations of target fish species—particularly river herring, shad and American eel—have declined nationwide. Because the success of this outcome is measured in part by the presence of target fish at restoration sites, this decline may hinder our efforts to measure progress toward this outcome. While the factors that affect fish populations—including water quality, climate change, bycatch (accidental catches that are then discarded) and overfishing—do not directly influence the achievement of our mileage goal, they do influence the overall recovery of target fish species.