RAPID: Morphological Effects of Extreme Sea-Level Anomalies

对项目的非技术性描述，解释项目的意义和重要性海岸侵蚀是一个具有国家和全球重要性的问题。随着越来越多的人沿着海岸生活，预测风暴和其他天气系统如何改变海岸线的景观变得越来越重要。这个快速项目将在海平面上升和厄尔尼诺现象期间从俄勒冈州海岸线收集大量实地数据，使海滩移动和侵蚀的数字模型更加准确。 海岸过程的数值模型被联邦/州政府机构、地方规划者和咨询机构广泛用于一系列工程和规划应用;因此，提高这些模型中形态演变的定量准确性有可能提高许多产品和服务的质量。该项目将在俄勒冈州的沿岸的单元实施一项海滩和沙丘地形测量活动，以量化极端海平面异常对海滩形态的影响。有待检验的假设是：1）在厄尔尼诺期间，俄勒冈州的岬角边界沿岸的单元内的大部分沙丘背海岸线是否将经历比正常年份多约10-15%的“碰撞状态”。沿海岸沿着的沙丘也将经历比典型年份更多的“过洗状态”; 2）沿岸的单元的南部范围将经历显著的侵蚀，并且将比北部受到更大的影响。沿岸沉积物输运的影响因素将从沿岸的单元南端侵蚀数万立方米的沙子，这些沉积物将向近海和北方输运;和3）在风暴之后和异常期结束时，向海滩提供的跨海岸沉积物，开始沙丘的恢复阶段，根据海滩形态测量，将在空间上高度可变，但将与沿岸沉积物输送中的局部梯度密切相关。 虽然人们普遍认为海平面异常和厄尔尼诺事件是如何影响美国西海岸沿着的海滩和沙丘的，但几乎没有可用的数据集，而且关于沉积物向岸输送的速率和机制的记录也很少。这项研究将量化的沉积物量损失的海滩在每个风暴事件，随后跟踪整个冬季和春季的空间和时间趋势，海滩恢复。

A non-technical description of the project, which explains the project's significance and importanceCoastal erosion is a problem of national and global importance. As more people live along the shore, it is becoming increasingly vital to forecast how storms and other weather systems can alter the landscapes of coastlines. This RAPID project will collect intensive field data from the Oregon coastline during a period of elevated sea level and El Niño conditions that will make numerical models of beach movement and erosion more accurate. Numerical models of coastal processes are widely used by federal/state government agencies, local planners, and consultancies for a range of engineering and planning applications; accordingly, enhancing the quantitative accuracy of morphological evolution in these models has the potential to improve the quality of many products and services. A technical description of the projectThis RAPID project will implement a beach and dune topographic surveying campaign in the Netarts littoral cell, Oregon to quantify the impacts of extreme sea level anomalies on beach morphology. Hypotheses to be tested are whether 1) the majority of the dune-backed coastline within Oregon's headland-bound littoral cells will experience the "collision regime" of the Sallenger storm impact scale approximately 10-15% more during El Niño than during normal years. Dunes along the coast will also experience the "overwash regime" significantly more than during a typical year; 2) the southern extent of littoral cells will experience significant erosion and will be more impacted than the north. Gradients in longshore sediment transport will erode on the order of tens of thousands of cubic meters of sand from the southern ends of littoral cells with that sediment being transported both offshore and northward; and 3) Cross shore sediment supply to the beach following storms and at the end of the anomalous period, initiating the recovery phase for the dunes, will be highly spatially variable based on beach morphometrics, but will be strongly correlated to local gradients in longshore sediment transport. Although there is a general sense of how sea level anomalies and El Niño events impact beaches and dunes along the U.S. West Coast, there are few data sets available and the rates and mechanisms of onshore feeding of sediment are poorly documented. This research will quantify the sediment volume lost from the beach during each storm event and subsequently track the spatial and temporal trends in beach recovery throughout the winter and spring.