RAPID: Collaborative Research: Tracking Hurricane Harvey's Storm Surge and Flood Sedimentation

四级飓风“哈维”是德克萨斯州 56 年来最强烈的风雨事件，于 2017 年 8 月 25 日登陆，最大持续风速为 130 英里/小时，风暴潮超过 2 m。此外，飓风还带来了 30 至 50 英寸的降雨，并在德克萨斯州东南部造成了破纪录的淡水洪水，河流和墨西哥湾的洪水淹没了大片沿海沼泽地。布拉索斯河、三一河和圣伯纳德河沿岸的内陆河流湿地也发生了严重的淡水洪水。哈维提供了一个绝佳的机会来研究罕见风雨事件的沉积特征，并通过记录地质记录中过去类似事件的沉积物来估计其重现期。此外，公众越来越意识到气候变化的有害影响，特别是在受到海平面加速上升威胁的沿海地区。这项研究将提供关于飓风在向沼泽贡献沉积物、造成沉积物堆积和抵消海平面上升导致的相对海拔损失方面的作用的新信息，有助于确定沿海沼泽是否能够在海平面上升的情况下生存。这是路易斯安那州立大学和北德克萨斯大学研究团队的一个合作项目，涵盖了飓风哈维沿德克萨斯州东南部沿海（咸水）到河流（淡水）横断面的完整沉积影响。迄今为止进行的研究表明，飓风是沼泽生长的主要贡献者，飓风沉积量（数百万公吨）超过了每年的河流和沿海沉积物输入量，但该主题仍然是争论了。 通过沿着淡水到海洋横断面的沼泽取芯，本研究的主要目标包括：(i) 记录德克萨斯州东南部沿海沼泽冲刷和洪水沉积的程度、特征和范围，以及 (ii) 测量前势屏障背风处冲刷沉积的程度和内陆范围，以评估屏障尺寸相对细微的增加是否会导致沼泽冲刷沉积程度的大幅减少。该研究将向沿海管理机构通报如何使用屏障来阻止或减少风暴过度冲刷，从而可能减少邻近沼泽的冲刷沉积量和内陆范围，而在海平面加速上升的情况下，这种沉积可能是沼泽生存的关键因素。这项研究还旨在生成德克萨斯州东南部飓风引发的极端事件长达数百年至数千年的多代理记录。这些长期记录对于估计哈维等极端事件的重现期至关重要，对于飓风和洪水风险评估以及沿海管理决策也至关重要。

Category 4 Hurricane Harvey, the most intense wind and rain event to strike Texas in 56 years, made landfall on August 25, 2017, with maximum sustained winds of 130 mph and a storm surge of over 2 m. In addition, the hurricane brought 30-50 inches of rain and caused record-breaking freshwater flooding throughout southeastern Texas, inundating large tracts of coastal marshes with flood waters from rivers and the Gulf of Mexico. Severe freshwater flooding also occurred in inland fluvial wetlands along the Brazos, Trinity, and San Bernard Rivers. Harvey provides an excellent opportunity to study the sedimentary signatures of a rare wind-and-rain event and to estimate its return period by documenting past similar event deposits in the geological record. In addition, there is growing public awareness of the detrimental effects of climate change, particularly in coastal areas threatened by accelerated sea-level rise. This research will help determine whether coastal marshes can survive rising sea-level by providing new information on the role of hurricanes in contributing sediment to marshes, causing accretion and counteracting relative elevation loss due to sea-level rise. This is a collaborative project by research teams at Louisiana State University and the University of North Texas encompassing the complete sedimentary impacts of Hurricane Harvey along a coastal (saltwater)-to-fluvial (freshwater) transect across southeastern Texas.Studies conducted to date suggest that hurricanes are major contributors to marsh growth, with themagnitude of Hurricane sedimentation (millions of metric tons) exceeding annual riverine and coastal sediment inputs, but the topic is still debated. Through marsh coring along the freshwater to marine transect, this study?s main objectives include: (i) documenting the magnitude, character and extent of washover and flood sedimentation in coastal marshes in southeast Texas, and (ii) to measure the magnitude and inland extent of washover sedimentation in the lee of foredune barriers to evaluate whether relatively subtle increases in barrier dimensions can cause substantial reductions in the magnitude of washover sedimentation in marshes. The study will inform coastal management agencies on the use of barriers to block or reduce storm overwash, potentially reducing washover sediment magnitude and inland extent in adjacent marshes, at a time when such sedimentation may be a crucial factor in survivability of marshes in the face of accelerating sea-level rise. This study also aims at producing centuries-to-millennia-long multi-proxy records of hurricane-generated extreme events for southeastern Texas. These long-term records are vital for estimating the return period of such extreme events as Harvey and is critically important for hurricane- and flood-risk assessments and coastal management decision-making.