A new longitudinal approach to assess hydrologic connectivity: Embanked floodplain inundation along the lower Mississippi River
A new longitudinal approach to assess hydrologic connectivity: Embanked floodplain inundation along the lower Mississippi River
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DOI：
10.1002/hyp.9838
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发表时间：
2013-07
影响因子：
3.2
通讯作者：
P. Hudson;M. A. Sounny-Slitine;M. LaFevor
中科院分区：
文献类型：
--
作者：
P. Hudson;M. A. Sounny-Slitine;M. LaFevor
水文连通性是理解沿蜿蜒河流走廊的洪泛平原过程的基础。本研究通过利用高分辨率光探测和测距DEM以及基于GIS的新方法来确定洪水阶段的精确高程，有助于了解水文连通性。该方法创建了一个高分辨率的纵向河道河岸剖面，可以详细检查河岸泛滥平原的水文连通性。简单的河道横断面方法很可能会导致对河漫滩淹没和曲流河漫滩水文连通性的严重低估，因为天然堤坝表面相对于河漫滩底部的高程存在差异，而且河道河岸剖面的高程存在相当大的变化。与河道堤岸淹没相比，洪泛区淹没的泄洪持续时间有很大差异。10%的泄洪持续时间与87%的洪泛区表面被淹没有关，而只有53%的河道岸线被淹没。当排水持续时间减少到35%以下时，就会出现明显的淹没阈值。虽然25%的持续时间导致很少的河道堤岸被淹没，但它淹没了50%的洪泛平原表面。与筑堤有关的洪泛平原借贷坑，代表了对密西西比河下游堤岸洪泛平原形态的持续人为影响，并被低流量淹没。调查结果为一个重要的河岸河流系统的水文连通性问题提供了新的思路，该系统以前很少关注其物理洪泛平原过程。版权所有©2013 John Wiley & Sons， Ltd
Hydrologic connectivity is fundamental to understanding floodplain processes along meandering river corridors. This study contributes to understanding hydrologic connectivity by utilizing a high resolution Light Detection and Ranging DEM with a new GIS‐based approach for identifying the precise elevation of flood stage. The method created a high‐resolution longitudinal channel bank profile, enabling a detailed examination of embanked floodplain hydrologic connectivity. A simple channel cross‐section approach is likely to result in a large underestimation of floodplain inundation and hydrologic connectivity along meandering river floodplains because of differences in the elevation of the natural levee surface relative to floodplain bottoms and the considerable variability in the elevation of the channel bank profile. There is a large disparity in discharge duration associated with floodplain inundation in comparison to river channel bank inundation. A discharge duration of 10% is associated with inundation of 87% of the floodplain surface whereas only 53% of the channel bank profile is overtopped. An apparent threshold in inundation occurs as the discharge duration decreases below about 35%. While a duration of 25% results in very little of the channel bank being overtopped, it inundates 50% of the floodplain surface. Floodplain borrow pits, which are created in association with dike construction, represent a constant anthropogenic influence on the lower Mississippi embanked floodplain morphology, and are inundated by low discharge magnitudes. The results of the investigation shed new light on the topic of hydrologic connectivity for an important embanked fluvial system that has previously received little attention concerning its physical floodplain processes. Copyright © 2013 John Wiley & Sons, Ltd.