CNH: Drowning of Developed Coastal Barriers: Investigating the Threshold Rates of Sea-Level Rise of the Geologic-Human System

沿海屏障、狭窄的桑迪或世界上沿着的沙嘴，在下一个世纪面临着不确定的未来。海平面上升的速度已经超过了过去几千年来的水平，预计到世纪末将大幅上升，这可能会淹没障碍。自然屏障通过向陆地迁移的过程对海平面上升作出反应-在风暴期间，过冲和破坏将沉积物转移到屏障后面。旨在保护沿海基础设施的人类活动，如建造海堤、建造丁坝、滋养海滩、稳定海湾或加固向上漂移的岬角，已经积累到了一个地球上前所未有的新地貌的地步。历史上，出现了“发达壁垒”。通常，在已开发的屏障上进行的工程活动可以防止或抵消过洗。两个关键问题指导这项研究：1）是否存在海平面上升的阈值率，超过该阈值率，沿海屏障将完全淹没？人类对海平面上升的反应是否会减轻或加剧整个系统中发达屏障的损失？一个由地质学家、数值建模师和经济学家组成的多学科团队将从事综合领域和建模研究，以研究屏障系统的行为并预测其命运。重点地质调查将调查屏障如何应对过去较高的海平面上升率（与本世纪晚些时候的预测相匹配）。数值模型将通过耦合自然沉积物输运过程和人类对海岸的改变，研究发达屏障系统在十年至百年时间尺度上的演变。将探讨不同的人类保护战略，比较协调和不协调的反应，并考虑是否知情和不知情的反应会导致不同的障碍未来。最重要的问题是，旨在保护基础设施和海滩娱乐的人类活动是否会使屏障系统更有可能整体崩溃或“淹没”。海平面上升导致的屏障海滩淹没是一个具有全球重要性的问题。随着海平面的上升，同样的波浪过程也会造成这些障碍的巨大变化。障碍物的作用不仅仅是被动地泛滥（就像浴缸一样）;风暴、海浪和潮汐可以重塑整个海岸线。屏障包含一个海滩，这是一种特别有价值的资源，并容纳大量的基础设施，包括住宅、度假胜地、酒店和道路。因此，人类对海岸变化的反应是推平海滩、抽沙和装甲海岸。这些活动对海岸自然发生的过程有什么长期影响？这项研究的目的是提供关于全球屏障系统如何应对海平面变化和减缓战略变化的指导方针，目的是确定最佳的社会对策，以减少由此造成的潜在经济损失。这项研究将涉及与利益攸关方和沿海管理人员的沟通，以获得他们的投入，以帮助制定和评估模型模拟的决策战略，并传播研究结果。该计划还将为学生提供跨学科培训，他们是下一代沿海研究人员，涉及沿海过程的各个方面。

AbstractCoastal barriers, narrow sandy islands or spits found along many of the world's coasts, face an uncertain future over the next century. Rates of sea-level rise already exceed those experienced over the last several thousand years and are predicted to be substantially greater by the end of the century, offering the potential that barriers could drown. Natural barriers respond to sea-level rise through a process of landward migration - during storms, overwash and breaching transfer sediment to the back of a barrier. Human activities intended to preserve coastal infrastructure, such as building seawalls, constructing groynes, nourishing beaches, stabilizing inlets, or armoring updrift headlands, have accumulated to the point where a new landform, unprecedented in earth?s history, has emerged: the "developed barrier". Typically, engineering activities on developed barriers prevent or counteract overwash. Two key questions guide this research: 1) Are there threshold rates of sea-level rise beyond which coastal barriers will drown completely? and 2) Will human responses to sea-level rise mitigate or exacerbate the potential for losses of developed barriers across entire systems? A multidisciplinary team of geologists, numerical modelers, and economists will engage in an integrated field and modeling study to examine the behavior and predict the fate of barrier systems. Focused geologic investigations will investigate how barriers responded to higher rates of sea-level rise in the past (rates that match those predicted for later this century). Numerical models will study the evolution of developed barrier systems at decadal to centennial time scales by coupling natural sediment transport processes and human alterations of the coast. Different human protection strategies will be explored, comparing coordinated versus uncoordinated responses and considering whether well-informed versus poorly informed responses result in different barrier futures. The most important question will be whether human activities intended to preserve infrastructure and beach recreation may make wholesale collapse, or "drowning" of barrier systems more likely.The drowning of barrier beaches due to sea-level rise is an issue of global importance. The same wave processes that created these barriers will cause them to change dramatically as sea levels rise. Barriers will do more than flood passively (like a bath tub); storms, waves, and tides can reshape entire coastlines. Barriers contain a beach, a resource that is particularly valued, and house significant amounts of infrastructure, including homes, resort complexes, hotels, and roadways. Accordingly, humans respond to coastal changes by bulldozing beaches, pumping sand, and armoring the coast. What are the long-term effects of these activities on the naturally occurring processes on the coast? This research aims to provide guidelines on how the global system of barriers will respond to changes in sea level and to changes in mitigation strategies, with a goal of identifying optimal societal responses to reduce the resulting potential economic losses. This research will involve communication with stakeholders and coastal managers to obtain their inputs to help formulate and assess decision-making strategies for model simulations and to disseminate the study findings. This program will also provide interdisciplinary training for students, who are the next generation of coastal researchers, on the diverse aspects of coastal processes.