Hyperpycnal River Plumes - an opportunity to study their transport and deposition in a controlled dam-removal experiment

直接来自河流和大陆架流体泥的超密度（高密度）流被认为控制了相当大的跨边缘沉积物输运，但由于这种大流量事件的不可预测性，很难进行研究。华盛顿奥林匹克山埃尔瓦河上的大坝拆除可能允许对此类事件进行研究。从2011年开始，埃尔瓦河上的两座水坝将在2年内拆除，在此期间，模型预测胡安·德富卡海峡将形成浊流和重力流（超密度羽流）。PI将利用这个机会，通过实时监测河流和近海的悬浮泥沙来研究高密度水流。他们假设，大坝拆除后不久排放的大部分沉积物将移动到相对较深的水域，因为高密度的羽流在波浪和水流的影响下移动。他们将研究四个具体的河流流量条件和埃尔瓦的两个峰值流量将允许这些条件进行单独调查。Hypercnal流量到海洋没有任何详细的研究之前，拟议的工作应该带来新的信息，这些难以捉摸的事件对沉积物的分散盆地的作用。PI计划将这项工作与一些基于实地的课程结合起来，并将支持一名研究生。

Hyperpycnal (high density) flows coming directly from the rivers and continental-shelf fluid muds are considered to control considerable cross-margin sediment transport but are difficult to study due to unpredictable nature of such large discharge events. Dam removal on Elwa River of the Olympic Mountains in Washington may allow the study of such events. Two dams will be removed over a 2-year period on the Elwa starting in 2011, during which time models predict turbidite formation and gravity flows (hyperpycnal plumes) in Juan de Fuca Straits. The PI will utilize this opportunity to study the high-density flows through real-time monitoring of suspended sediment in the rivers and offshore. They hypothesize that most of the sediment discharged soon after dam removal will move to relatively deep water as high density plumes move below the influence of waves and currents. They will study four specific river discharge conditions and the two peak discharges on Elwa will allow these conditions to be investigated individually.Hyperpycnal flows to the ocean have not been studied in any detailed before and the proposed work should bring new information on the role of these elusive events on the dispersal of sediment to the basins. The PIs plan to incorporate the work with some field based courses and will support one graduate student.