SGER: The Aftermath of Hurricane Floyd: Assessment of the Geomorphic Effectiveness of the 1999 Flood on the Tar River, North Carolina

由于地层学记录中个别事件的罕见和难以识别，很少有研究考察个别大洪水事件对洪泛区沉积的影响。虽然大量的研究表明，中等水流事件与泥沙输移和河道形态之间存在着很强的关系，但大洪水在景观改变中的作用仍然不确定。1999年9月由飓风丹尼斯和弗洛伊德引起的北卡罗来纳州东部的特大洪水为检验低频、高强度洪水的地貌有效性提供了一个不同寻常的机会。这项拟议的研究通过(1)测量和绘制沉积、洪水冲刷和颗粒大小的空间模式，(2)将这些模式与洪水平原特征联系起来，(3)将现场数据与美国地质调查局测量的泥沙负荷进行比较，以及(4)量化洪水沉积物中几种与沉积物相关的污染物的储存和位置，来检验北卡罗来纳州焦油河沿岸滩地沉积的规模和空间变异性。现场数据将从焦油河对岸五个横断面的大约100-150个样本点收集。这些数据将被应用粒度分析、化学分析和空间分析进行分析。该项目的意义在于提供了一个很少收集到的有用数据集。这些数据和相关研究将有助于我们更好地了解罕见洪水期间的基本泥沙输运和沉积动力学，并将使我们能够与更受控制的河流系统中罕见洪水的动力学进行比较。这项研究还将提供必要的额外证据，以了解沉积记录中大型灾难性事件的重要性。

Because of the infrequent occurrence and the difficulty of recognizing individual events in the stratigraphic record, few studies have examined the impacts of individual, large flood events on floodplain sedimentation. Although a considerable amount of research has demonstrated that a strong relationship exists between moderate flow events and sediment transport and channel morphology, the role of large floods in landscape modification remains uncertain.The extraordinary floods of September 1999 in eastern North Carolina resulted from hurricanes Dennis and Floyd provide an unusual opportunity to examine the geomorphic effectiveness of a low frequency, high magnitude flood. The proposed study examines the magnitude and spatial variability of floodplain sedimentation along the Tar River, North Carolina by (1) measuring and mapping spatial patterns of sedimentation, floodplain scour, and particle size, (2) linking these patterns to floodplain characteristics, (3) comparing the field data with sediment loads measured by the U.S. Geological Survey, and (4) quantifying the storage and location of several sediment-associated contaminants in the flood deposits. Field data will be collected from about 100-150 sample sites along five transects across the Tar River. Particle size analysis, chemical analysis, and spatial analysis will be applied to analyze these data.The significance of the project is to provide a useful data set that can rarely be collected. The data and the associated research will help improve our understanding of basic sediment transport and deposition dynamics during rare floods and will allow comparisons with the dynamics of rare floods on more controlled river systems. The research will also provide additional evidence necessary to understand the importance of large, catastrophic events in the sedimentary record.