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

4级飓风哈维是56年来袭击德克萨斯州最强烈的风雨事件，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米。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引发了破纪录的淡水洪水，河流和墨西哥湾的洪水沃茨淹没了大片沿海沼泽。巴西河、Trinity河和圣伯纳德河沿着的内陆河流湿地也发生了严重的淡水洪水。哈维提供了一个很好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来估计其重现期。此外，公众日益认识到气候变化的有害影响，特别是在受海平面加速上升威胁的沿海地区。这项研究将有助于确定沿海沼泽地是否能在海平面上升的情况下生存下来，因为它提供了关于飓风在向沼泽地提供沉积物、造成堆积和抵消海平面上升造成的相对海拔损失方面所起作用的新信息。这是路易斯安那州立大学和北德克萨斯大学的研究小组合作开展的一个项目，涵盖了飓风哈维沿着海岸的完整沉积影响（咸水）-河流（淡水）横穿得克萨斯州东南部的样带。迄今为止的研究表明飓风是沼泽生长的主要原因，飓风造成的沉积物（数百万公吨）超过了每年河流和沿海沉积物的输入量，但这个问题仍然存在争议。 通过沼泽取芯沿着淡水到海洋样带，这项研究？的主要目标包括：（i）记录的规模，性质和范围的冲刷和洪水沉积在得克萨斯州东南部沿海沼泽，（ii）测量的规模和内陆范围的冲刷沉积在背风的foredune障碍，以评估是否相对微妙的增加障碍尺寸可以导致大幅减少的规模冲刷沉积在沼泽。这项研究将为沿海管理机构提供信息，说明如何利用障碍物阻挡或减少风暴的过度冲刷，从而有可能减少冲刷沉积物的规模和邻近沼泽地的内陆范围，而此时这种沉积可能是海平面加速上升时沼泽地能否生存的一个关键因素。这项研究还旨在为德克萨斯州东南部的飓风产生的极端事件产生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.