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John Wesley Powell Center for Analysis and Synthesis

Powell Center Working Group Project Information
Dam removal: synthesis of ecological and physical responses

Principal Investigator(s):
James E O'connor (Oregon Water Science Center)
Jeff Duda (Western Fisheries Research Center)
Amy East (Pacific Coastal and Marine Science Center)
Chauncey W Anderson (Oregon Water Science Center)

Patrick J Connolly (Columbia River Research Laboratory, WFRC)
James Ryan Bellmore (U.S. Geological Survey)
Jonathan Warrick (Pacific Coastal and Marine Science Center)
Jon J Major (USGS Volcano Science Center)
Patrick B Shafroth (Fort Collins Science Center)
Christopher S Magirl (Washington Water Science Center)
Christian Torgersen (Cascadia Field Station, FRESC)
Melissa M Foley (Pacific Coastal and Marine Science Center)
Samantha L Greene (Cascadia Field Station, FRESC)
Jennifer Bountry (Bureau of Reclamation)
Gordon Grant (U.S. Forest Service)
Mathias Collins (National Oceanic and Atmospheric Administration)
Desiree Tullos (Oregon State University)
Andrew Wilcox (University of Montana)
Francis Magilligan (Dartmouth College)
Timothy J Randle (Bureau of Reclamation)
Laura Craig (American Rivers)
James E Evans (Bowling Green State University)

Award Date: 2014 

Dam decommissioning is rapidly emerging as an important river restoration strategy in the U.S., with several major removals recently completed or in progress. But few studies have evaluated the far-reaching consequences of these significant environmental perturbations, especially those resulting from removals of large (>10-15 m tall) structures during the last decade. In particular, interactions between physical and ecological aspects of dam removal are poorly known. From recent work, however, observations are now available from several diverse settings nationwide to allow synthesis of key physical and ecological processes associated with dam removals, including fish and benthic community response, reservoir erosion, downstream sedimentation, water quality issues (including turbidity and contaminant transport), riparian vegetation, food web response, gene flow changes, effects on migratory aquatic species, and invasive species response. Our proposed examination and synthesis of these observations, framed and tested as hypotheses and conceptual models, will provide better understanding of the multifaceted and interrelated consequences of dam decommissioning, thereby providing a basis for formulating realistic expectations for river restoration in addition to identifying key information gaps and research needs.

Publications and Products:
Bellmore, J.R., K.M. Vittum, J.J. Duda, and S. Greene. 2015. USGS dam removal science database. Available online at

Bellmore J. Ryan, Duda Jeffrey J., Craig Laura S., Greene Samantha L., Torgersen Christian E., Collins Mathias J., Vittum Katherine. Status and trends of dam removal research in the United States. WIREs Water 2016. doi: 10.1002/wat2.1164

Bellmore J.R., Pess, G.R, Duda, J.J., O’Connor, J.E, East, A.E., Foley, M.M., Wilcox, A.C., Major, J.J., Shafroth, P.B., Morley, S.A., Magirl, C., Anderson, C.W., Evans, J.E., Torgersen, C.E., Craig, L.S. Conceptualizing Ecological Responses to Dam Removal: If You Remove It, What's to Come?, BioScience, Volume 69, Issue 1, 1 January 2019, Pages 26-39,

Collins, Mathias J., Noah P. Snyder, Graham Boardman, William S.L. Banks, Mary Andrews, Matthew E. Baker, Maricate Conlon, et al. “Channel Response to Sediment Release: Insights from a Paired Analysis of Dam Removal.” Earth Surface Processes and Landforms, January 1, 2017, n/a-n/a. doi:10.1002/esp.4108.

Duda, Jeffrey J., Daniel J. Wieferich, R. Sky Bristol, J. Ryan Bellmore, Vivian B. Hutchison, Katherine M. Vittum, Laura Craig, and Jonathan A. Warrick. “Dam Removal Information Portal (DRIP)-A Map-Based Resource Linking Scientific Studies and Associated Geospatial Information about Dam Removals.” Report. Open-File Report. Reston, VA, 2016. USGS Publications Warehouse.

Foley, M. M., Bellmore, J.R., O’Connor, J.E., Duda, J.J., East, A.E., Grant, G.E., Anderson, C.W., Bountry, J.A., Collins, M.J., P. J. Connolly, Craig, L.S., Evans, J.E., Greene, S.L., Magilligan, F.J., Magirl, C.S., Major, J.J., Pess, G.R., Randle, T.J., P. B. Shafroth, Torgersen, C.E., Tullos, D., and Wilcox, A.C. (2017), Dam removal: Listening in, Water Resources Research, 53, doi:10.1002/2017WR020457.

Foley, M.M., Magilligan, F.J., Torgersen, C.E., Major, J.J., Anderson, C.W., Connolly, P.J., Weiferich, D., Shafroth, P.B., Evans, J.E., Infante, D., and Craig, L.S. (2017) Landscape context and the biophysical response of rivers to dam removal in the United States. PLOS ONE 12(7): e0180107.

Magilligan, F. J., Graber, B. E., Nislow, K. H., Chipman, J. W., Sneddon, C. S., & Fox, C. A. (2016). River restoration by dam removal: Enhancing connectivity at watershed scales. Elementa: Science of the Anthropocene, 4(1), 000108.

Major, J.J., East, A.E., O'Connor, J.E., Grant, G.E. Wilcox, A.C., Magirl, C.S., Collins, M.J., Tullos, D.D., 2017, Geomorphic responses to dam removal in the United States-a two-decade perspective, in Tsutsumi, D. and Laronne, J.B., editors, Gravel-Bed Rivers: Processes and Disasters. John Wiley and Sons, p. 355-383.

O'Connor, J. E., Duda, J. J., and Grant, G. E., (2015). 1000 dams down and counting. Science 348 (6234), 496-497. doi: 10.1126/science.aaa9204

O'Connor, J. and East, A., (2014). Synthesizing Studies of Dam Removal. Eos Trans. 95 issue 40. 363-64 doi:10.1002/2014EO400003 [meeting report].

Tullos, Desirée D., Mathias J. Collins, J. Ryan Bellmore, Jennifer A. Bountry, Patrick J. Connolly, Patrick B. Shafroth, and Andrew C. Wilcox, 2016. Synthesis of Common Management Concerns Associated with Dam Removal. Journal of the American Water Resources Association (JAWRA) 1-28. DOI: 10.1111/1752-1688.12450

USGS Dam Removal Information Portal (DRIP)

Warrick, J.A., Bountry, J.A., East, A.E., Magirl, C.S., Randle, T.J., Gelfenbaum, G., Pess, G.R., Leung, V., and Duda, J.J. (2015). Large-scale dam removal on the Elwha River, Washington, USA: Source-to-sink sediment budget and synthesis. Geomorphology 246:729-750. doi: 10.1016/j.geomorph.2015.01.010

Welty, E.Z. 2015. linbin: Binning and plotting of linearly referenced data. R package version 0.1.

Welty, E.Z, Torgersen, C.E., Brenkman, S.J., Duda, J.D., and Armstrong, J.B. (2015). Multiscale analysis of river networks using the linbin R package. North American Journal of Fisheries Management. 35(4):802-809.

USGS Mission Areas:
Ecosystems Science
Water Science
Environmental Health Science

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