Cooperative Fish and Wildlife Research Units Program: Massachusetts
Education, Research and Technical Assistance for Managing Our Natural Resources

Massachusetts Project

Restoring Aquatic Habitats through Dam Removal

July 2018 - June 2023


Participating Agencies

  • U.S. Geological Survey
  • Massachusetts Division of Fisheries and Wildlife
  • Massachusetts Environmental Trust
  • Massachusetts Division of Ecological Restoration

There are thousands of small dams in Massachusetts that fragment and impair nearly every stream and river throughout the state, altering fish passage, flow, sediment, and nutrient movement, and making these ecosystems less resilient to natural and anthropogenic disturbances. To date, nearly 60 dams have been removed in the state, yet only a fraction of these streams have been monitored to assess water quality, habitat, and biotic responses to dam removal. Information on the benefits of dam removal, including the watershed and long-term impacts of these changes, are critical for the public to understand expectations following dam removal and to gain support for future dam removals. We also need a better understanding of ecological changes following dam removal in order to better answer questions from local, regional, and national regulatory community that impact our ability to advance projects. Over the last three years, extensive pre-removal data has been collected on temperature, dissolved oxygen, and macroinvertebrates at 12 dam removal sites across Massachusetts through a partnership with researchers at the University of Massachusetts (UMass) and the Massachusetts Division of Ecological Restoration (MDER). These data showed that most sites had significant warming downstream of dams, highlighting the potential for extensive consequences of dams on biota, particularly coldwater fishes. However, the magnitude and extent of effects of dams are highly variable across sites and raise additional questions. Here, we propose to continue sampling these 12 sites plus 3 additional coldwater streams to quantify water quality, macroinvertebrate, and fish responses to dam removal. We will use the extensive fish database for Massachusetts and collaborate with UMass, MDER, and the Massachusetts Division of Fisheries and Wildlife (MassWildlife) to add additional sites for a broader assessment of fish responses. The results will be used to model the collective ecological benefits of dam removal statewide and will be synthesized into outreach materials highlighting these benefits to promote future dam removal toward increasing the quality and resilience of stream ecosystems.

Research Publications Publication Date
Abbott, K.M., P.A. Zaidel, A.H. Roy, K.M. Houle, and K.H. Nislow. 2022. Investigating impacts of small dams and dam removal on dissolved oxygen in streams. PLoS ONE 17: e0277647. DOI: 10.1371/journal.pone.0277647 | Publisher Website November 2022
Abbott, K., A. Roy, and K. Nislow. 2022. Restoring aquatic habitats through dam removal. U.S. Department of Interior, Fish and Wildlife Service, Cooperator Science Series FWS/148-2022, Washington, DC. | Publisher Website November 2022
Presentations Presentation Date
Roy, A.H., K.M. Abbott, M.B. Cole, K.M. Houle, and K.H. Nislow. 2019. Impacts of small, low-head dams on stream macroinvertebrate assemblages. Annual Meeting of the Society for Freshwater Science, 19-23 May 2019, Salt Lake City, UT. May 2019
Abbott, K.M., A.H. Roy, M.B. Cole, K.M. Houle, and K.H. Nislow. 2019. Variable responses of aquatic macroinvertebrate assemblages to dam removal. Society of Wetland Scientists – New England Chapter Fall Meeting: Dammed If You Do and Dammed If You Don’t: Barrier Removal and Stream Integration, 4-5 October 2019, New Britain, CT. October 2019
Theses and Dissertations Publication Date
Macpherson, C.B.M. 2023. Fish assemblage responses to dam removals. BS Honor's Thesis. University of Massachusetts Amherst. May 2023
Abbott, K.M. 2023. River restoration through dam removal: Examining ecological responses to small dam removals across Massachusetts. PhD dissertation, Department of Environmental Conservation, University of Massachusetts Amherst. September 2023