Hydraulics and Sediment Transport of Cataclysmic Flows

与激变流有关的地貌过程不能直接测量。因此，对与这些极端水文事件有关的水流条件、泥沙运移、侵蚀和沉积阈值以及能量消耗模式的了解很少。古水力和古水文技术的最新发展为定量探索这些现象提供了一条途径。晚更新世，爱达荷州南部的Snake河和Big Lost河，以及华盛顿州东部的海峡Scabland发生了灾难性的洪水，为这些方法的应用提供了一个极好的现场实验室。利用最大流量阶段的现场证据，结合阶跃回水模型和水力演进模型，我们建议重建这些水流的水力学参数(流量、流速、剪应力和单位面积水流功率)。据推测，这些变量及其空间变化可能与沉积和侵蚀阈值的丰富野外证据直接相关。我们将在几个不同的尺度和不同的流动环境中测试这些关系，以确定它们对灾难性洪水淹没地形的普遍适用性。

Geomorphologic processes associated with cataclysmic flows defy direct measurement. As such, very little is understood regarding flow conditions, sediment transport, erosional and depositional threshold, and patterns of energy expenditure associated with these extreme hydrologic events. Recent develop- ments in paleohydraulic and paleohydrologic techniques provide an avenue for quantitative exploration of these phenomena. Late Pleistocene cataclysmic flooding along the Snake and Big Lost Rivers of southern Idaho and in the Channeled Scabland of eastern Washington has provided an excellent field laboratory for application of these methodologies. Utilizing field evidence of maximum flow stages in conjunction with step-backwater and hydraulic flow routing models, we propose to reconstruct the hydraulics (discharge, velocity, shear stress, and unit-area stream power) of these flows. It is hypothesized that these variables, and their spatial variations, can be directly related to the abundant field evidence of depositional and erosional thresholds. We will test these relationships at several different scales and within different flow environments to determine their general applicability for cataclysmically flooded terrains.