Breaking Down Barriers: Reviewing Twenty Years of Dam Removal Science in the United States

The practice of dam removal has increased in recent years due to aging infrastructure, changing societal needs, and modern safety standards.  Yet, science is just beginning to guide our understanding of the physical and ecological implications of dam removal. Ultimately, however, deciding if and how to remove dams should be informed, at least in part, by the “lessons learned” from dam removal monitoring studies.  We conducted an extensive literature search to identify all published, and many unpublished, dam removal science studies in the United States.  Here we compare our  results to information from a comprehensive dam removal database maintained by American Rivers and we ask three important questions: 1) is dam removal science representative of dam removal practice in terms of the number, location and size of removed dams; 2) what is the character of dam removal monitoring studies—what responses are being measured, for how long, and what study designs are being employed; and (3), what gaps exist that might impede science from better informing practice?  Our analyses can catalyze needed discussions about how limited monitoring resources can be better distributed to inform dam removal planning, prioritization, and implementation.