RAPID: Analysis of the May 2015 Texas Flood with a Connectivity Framework and High Resolution Topography Data

经过四年的严重干旱，2015年5月25日至26日，德克萨斯州中部经历了大规模洪水。现在很清楚的是，以前从未有过这样规模的事件，几个地方的月降水总量达到了20英寸。仅5月25日至26日这一事件就带来了10英寸的降雨。洪水泛滥的河流数量巨大，受影响地区的空间范围横跨德克萨斯州的整个中部地区，从奥斯汀和休斯顿等主要城市中心到温伯利和巴斯托普等小城镇。该提案寻求使用机载遥感技术立即获取高分辨率地形数据，以评估阵亡将士纪念日洪水的影响。这些数据将由休斯顿大学的国家航空激光测绘中心获取。数据分析将在德克萨斯大学奥斯汀分校进行。本研究的目的是量化该极端事件期间河道与漫滩之间的水文和沉积连通性及其对下游输沙的影响。这些知识对于通过更好地了解在重大风暴事件期间侵蚀和沉积将发生的地方，为可持续流域管理提供信息至关重要。为该项目收集的数据将立即公开，并与工程界共享，以帮助评估受洪水影响的桥梁和水坝的结构损坏。这些数据还将用于一个案例研究，以培训2015年夏季研究所的46名研究生，该研究所是国家洪水互操作性实验的一部分。该团队将测试一个假设，即河道-洪泛平原的连通性影响下游泥沙的运输，特别是由于泥沙在洪泛平原上的分散和储存，河道-洪泛平原的高连通性导致下游泥沙运输减少。为了验证这一假设，该研究以两个截然不同的区域为目标：下三一河（Lower Trinity River）——德克萨斯州一条主要的蜿蜒河流，沉积物运输是正在进行的研究的主题，以及奥斯汀市中心的城市环境。在2015年5月的事件中，这两个地区都经历了严重的洪水条件，但它们的洪泛平原却大不相同。分析工作将使用地形分析工具GeoNet，结合洪水后的实地工作，并加强国家洪水互操作性实验中使用的模拟和预报模型。数据将存储在nsf资助的OpenTopography存储库中，供广大社区访问。研究结果将通过开放获取的出版物和会议报告传播，作为分析的一部分使用的工具将以开源格式提供给社区。

After four years of severe drought, central Texas experienced massive flooding on 25-26 May 2015. It is now clear that an event of this magnitude had never been recorded before, with monthly precipitation totals reaching 20 inches at several locations. The 25-26 May event alone contributed 10 inches of rain. The number of rivers in flood was enormous as was the spatial extent of the affected areas spanning the entire central portion of Texas from major city centers such as Austin and Houston to smaller towns such as Wimberley and Bastrop. This proposal seeks immediate acquisition of high-resolution topography data using airborne remote-sensing technology to assess the impact of the Memorial Day Floods. The data will be acquired by the National Center for Airborne Laser Mapping at the University of Houston. Data analysis will be conducted at the University of Texas at Austin. The objective of the proposed research is to quantify the hydrological and sedimentological connectivity between river channel and floodplain during this extreme event and its impact on downstream sediment transport. Such knowledge is fundamental for informing sustainable catchment management through better understanding of where erosion and sedimentation will occur during major storm events. The data collected for this project will immediately be made publically available and shared with the engineering community to aid in assessing the structural damage to bridges and dams impacted by the floods. The data will also be used in a case study to train 46 graduate students at a 2015 Summer Institute that is part of the National Flood Interoperability Experiment.The team will test a hypothesis that channel-floodplain connectivity influences downstream sediment transport, and in particular that high channel-floodplain connectivity resulted in reduced downstream sediment transport due to sediment dispersal and storage on the floodplain. To test this hypothesis, the study targets two contrasting areas: the Lower Trinity River--a major meandering river in Texas where sediment transport is the subject of ongoing research, and an urban setting in downtown Austin. Both experienced major flooding conditions during the May 2015 event, but their floodplains are quite different. Analytical work will use the topography analysis tool GeoNet in conjunction with post-flood fieldwork and enhancement of simulation and forecasting models used in the National Flood Interoperability Experiment. The data will be stored in the NSF-funded OpenTopography repository for access by the community at large. Research results will be disseminated through open-access publications and conference presentations, and the tools used as part of the analysis are available to the community in open-source format.