Collaborative Research: Linking landscape evolution and paleoflood hydrology in a megaflood dominated landscape, Channeled Scablands, eastern Washington, USA

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Cataclysmic draining of glacial lakes has generated the largest known floods on Earth, and these floods in turn have carved dramatic canyon landscapes. The Channeled Scablands in eastern Washington are an exceptional example of such a landscape, where the Missoula Floods scoured vast tracts of the Pacific Northwest at the end of the last Ice Age. Multiple, earlier glacial advances are known to have occurred in the region, which potentially were associated with their own phases of mega-flooding. This project will investigate the role these earlier floods played in carving the Channeled Scablands. Megafloods are important to understand because, in addition to the local cataclysm, they may have altered global climate. Similar floods also occurred on Mars, and understanding their erosive power is key to reconstructing the size of floods on that planet. The study area is one of the major features of American Geology and has long captivated people from all backgrounds. It is the site of the proposed Ice Age Floods National Geologic Trail, hence there will be opportunities to broadly disseminate the scientific results. The project includes an educational component that will train graduate students and partner with a nationally recognized program designed to engage girls 12-18 years of age in the exploration of science, technology, engineering and mathematics.Late-Pleistocene glacial outburst floods caused dramatic landscape change in the Channeled Scablands and many other landscapes. However, little is known about how the topography of landscapes subjected to mega-floods evolved over time as it was subjected to repeated floods during multiple glacial advances. To address this knowledge gap, an interdisciplinary study will be used to reconstruct the Pleistocene history of Channeled Scablands landscape evolution. Cosmogenic nuclide surface exposure dating and hydraulic modeling at several sites within the Channeled Scablands will be used to test multiple hypotheses concerning the timing of canyon formation and landscape evolution. The expected outcome of this work is new insight into the topographic evolution of landscapes subject to repeated cataclysmic floods.