Channel Properties Where Fluvial and Tidal Currents Meet

该项目将研究潮汐在向河口上游推进数十至数百公里时如何消耗能量，并导致河流水流逆转。这项工作是新颖的，具有重要的科学意义，因为它为连接河流连续体的两个部分--河流和河口水道--提供了一个水动力学框架，在此之前，这两个部分是分开处理的。我们将测量河道尺寸、泥沙特性、流速剖面和河流紊动应力，并模拟潮汐向上游推进时能量的变化。在河段水流从单纯向下游流动转变为受潮汐影响的河段，我们假设潮汐能量耗散过程导致河床侵蚀加剧，从而形成一种特有的河流形态。这项研究的结果将有助于揭示：1)如何管理大坝泄洪，以最大限度地减少下游的侵蚀；2)河床生境的发展和稳定；以及3)向海岸带排放泥沙。此外，这项工作将有助于描述海平面上升对遥远内陆河流的影响。

This project will investigate how energy in tides is consumed as they advance tens to hundreds of kilometers upstream of the river mouth, and cause river currents to reverse. This work is novel and scientifically important because it provides a hydrodynamic framework for linking two parts of the river continuum, fluvial and estuarine channels, which heretofore had been treated separately. We will measure channel dimensions, sediment properties, velocity profiles, and turbulent stresses in river flows, and model the changes in energy as tides advance upstream. In the section of the river where flows transition from solely downstream flow to becoming influenced by tides, we hypothesize that tidal energy dissipation processes lead to enhanced riverbed erosion, giving rise to a characteristic river form. Findings from this study will help shed light on: 1) how to manage dam water releases to minimize erosion downstream, 2) the development and stability of river bed habitats, and 3) sediment discharge to the coastal zone. Moreover, this work will help characterize the effects of sea level rise on rivers far inland.