RUI and COLLABORATIVE RESEARCH: Impact of Extrafluvial Events on River Valley Evolution

科学价值该项目将调查大型、罕见的地质事件，如山体滑坡或熔岩流，对哥伦比亚河盆地内陆半干旱、隆起的火山高原基岩河谷演化的影响。这些事件被称为“外流”，因为它们是在河道本身之外发起的，但通过改变河道坡度和宽度、掩埋谷底或建造临时水坝，一旦发生破坏，可能会产生灾难性的洪水，从而改变河流。我们假设，这些周期性的河道侵蚀事件是创造和维持许多河流峡谷地貌特征的主导力量。俄勒冈州东南部的Owyhee河是探索这些灾难性事件的单独和综合影响的主要野外地点。将利用地理空间分析绘制地图并了解这些过程在该区域其他河流上的分布情况。根据这些结果，将进行河流规模的切割潜力计算，以定量地解决滑坡/熔岩入侵与河道演变之间的关系。这些结果将通过改善河流切割山谷的过程的表现，为迅速扩大的景观建模领域做出贡献。更广泛的影响中央华盛顿大学(CWU)和刘易斯与克拉克学院(LCC)主要是本科院校；学生将在本科课程中进行地理空间分析，通过大学户外计划参加实地考察，并直接与调查人员合作。CWU的科学人才扩展计划，部分针对科学中代表性不足的群体的学生，将成为招募参与者的来源。与美国地质调查局和美国林业局的科学家密切合作将有助于将结果传播给利益相关者。该项目将有助于了解大型滑坡水坝造成的地质灾害，并对评估拆除人工建造的水坝对河道的影响具有影响。

Scientific MeritThe project will investigate the impacts of large, rare geologic events, such as landslides or lava flows, on the evolution of bedrock river valleys in the semi-arid, uplifted volcanic plateaus of the interior Columbia River basin. These events are termed "extrafluvial" because they are initiated outside of the river channel itself, but alter the river by changing the channel slope and width; burying the valley bottom; or creating temporary dams that can generate cataclysmic floods upon failure. We hypothesize that these periodic channel-encroaching events are a dominant force in creating and maintaining the geomorphic features of many river canyons. The Owyhee River in southeastern Oregon is the principal field site in which the individual and combined impacts of these catastrophic events will be explored. Geospatial analyses will be used to map and understand the distribution of these processes on other rivers in the region. From these results, reach-scale calculations of incision potential will be made to address quantitatively the relations between landslide/lava invasions and river channel evolution. The results will contribute to the rapidly expanding field of landscape modeling by improving representations of the processes by which rivers carve their valleys. Broader ImpactsCentral Washington University (CWU) and Lewis and Clark College (LCC) are primarily undergraduate institutions; students will conduct the geospatial analysis in an undergraduate course, participate in field trips through the College Outdoors Program, and work directly with investigators. The Science Talent Expansion Program at CWU, partially targeted at students from underrepresented groups in science, will be a source for recruiting participants. Close collaborations with scientists at the U.S. Geological Survey and U.S Forest Service will help disseminate results to stakeholders. The project will contribute to an understanding of geologic hazards posed by large landslide dams and has implications for assessing river-channel impacts of removing human-constructed dams.