Impact of Flow Regimes on Fish Populations

Mary Freeman and Seth Wenger are leading a working group of ecologists from across the U.S. to improve the understanding of how dams, water withdrawals, and other flow modifications affect fish. While it is generally accepted that fish species are adapted to specific flow regimes (for example, high flows in the winter, low flows in the summer), it is still not well understood how changes to the flow regime affect individual species. With funding from the US Army Corps of Engineers and support from the US Geological Survey’s Powell Center, the team convened in Fort Collins, Colorado in April, 2019 for a four-day meeting to chart a new approaches to studying flow ecology. Since then, the team has been developing a series of papers that propose specific, mechanistic hypotheses for how different flows affect species with different characteristics, alongside new approaches to test these hypotheses with long-term datasets from across the country.