Morphodynamic evolution following sediment release from the world’s largest dam removal

Andrew C. Ritchie; Jonathan Warrick; Amy E. East; Christopher S. Magirl; Andrew W. Stevens; Jennifer A. Bountry; Timothy J. Randle; Christopher A. Curran; Robert C. Hilldale; Jeffrey J. Duda; Ian M. Miller; George R. Pess; Emily Eidam; Melissa M. Foley; Randall McCoy; Andrea S. Ogston

doi:10.1038/s41598-018-30817-8

Morphodynamic evolution following sediment release from the world’s largest dam removal

Scientific Reports

By: Andrew C. Ritchie, Jonathan Warrick, Amy E. East, Christopher S. Magirl, Andrew W. Stevens, Jennifer A. Bountry, Timothy J. Randle, Christopher A. Curran, Robert C. Hilldale, Jeffrey J. Duda, Ian M. Miller, George R. Pess, Emily Eidam, Melissa M. Foley, Randall McCoy, and Andrea S. Ogston

https://doi.org/10.1038/s41598-018-30817-8

Links

More information: Publisher Index Page (via DOI)
Open Access Version: Publisher Index Page
Download citation as: RIS | Dublin Core

Abstract

Sediment pulses can cause widespread, complex changes to rivers and coastal regions. Quantifying landscape response to sediment-supply changes is a long-standing problem in geomorphology, but the unanticipated nature of most sediment pulses rarely allows for detailed measurement of associated landscape processes and evolution. The intentional removal of two large dams on the Elwha River (Washington, USA) exposed ~30 Mt of impounded sediment to fluvial erosion, presenting a unique opportunity to quantify source-to-sink river and coastal responses to a massive sediment-source perturbation. Here we evaluate geomorphic evolution during and after the sediment pulse, presenting a 5-year sediment budget and morphodynamic analysis of the Elwha River and its delta. Approximately 65% of the sediment was eroded, of which only ~10% was deposited in the fluvial system. This restored fluvial supply of sand, gravel, and wood substantially changed the channel morphology. The remaining ~90% of the released sediment was transported to the coast, causing ~60 ha of delta growth. Although metrics of geomorphic change did not follow simple time-coherent paths, many signals peaked 1–2 years after the start of dam removal, indicating combined impulse and step-change disturbance responses.

Study Area

Additional publication details
Publication type	Article
Publication Subtype	Journal Article
Title	Morphodynamic evolution following sediment release from the world’s largest dam removal
Series title	Scientific Reports
DOI	10.1038/s41598-018-30817-8
Volume	8
Year Published	2018
Language	English
Publisher	Springer Nature
Contributing office(s)	Arizona Water Science Center, Pacific Coastal and Marine Science Center, Washington Water Science Center, Western Fisheries Research Center
Description	13279, 13 p.
Country	United States
State	Washington
Other Geospatial	Elwha Dam, Elwha River, Olympic National Park
Google Analytic Metrics	Metrics page