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

CNH：发达沿海屏障的淹没：研究地质-人类系统海平面上升的阈值率

• 批准号: 0815875
• 负责人: Andrew Ashton
• 金额: $ 139.99万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0815875&HistoricalAwards=false
• 关键词: CNH; Drowning; Developed; Coastal; Barriers

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.

海岸屏障、狭窄的沙岛或在世界上许多海岸发现的唾沫，在下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所经历的速度，预计到本世纪末，海平面上升的速度将大大超过这一速度，从而提供了障碍可能被淹没的可能性。天然屏障通过向陆地迁移的过程来应对海平面上升--在风暴期间，冲刷和决口将沉积物转移到屏障的后面。旨在保护沿海基础设施的人类活动，如修建海堤、修筑丁坝、滋养海滩、稳定入海口或装甲逆流海角，已经积累到这样的程度，以至于出现了一种在地球历史上前所未有的新地貌--S：“发达的屏障”。通常情况下，在已开发的屏障上进行工程活动可以防止或抵消溢流。指导这项研究的两个关键问题：1)海平面上升的门槛速率是否存在，超过这个门槛，沿海屏障将完全被淹没？2)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可能性？一个由地质学家、数值模型师和经济学家组成的多学科团队将从事一项综合的领域和建模研究，以检查屏障系统的行为并预测其命运。重点地质调查将调查障碍对过去更高的海平面上升速度(与本世纪晚些时候预测的速度相匹配)的反应。数值模型将结合自然泥沙输送过程和人类对海岸的改变，研究已发展的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，比较协调与不协调的应对措施，并考虑知情的应对措施与不了解情况的应对措施是否会导致不同的障碍未来。最重要的问题将是，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大规模坍塌或“溺水”。海平面上升导致屏障海滩溺水是一个具有全球重要性的问题。造成这些障碍的波浪过程将导致它们随着海平面上升而发生戏剧性的变化。障碍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。障碍包括海滩，这是一种特别有价值的资源，并容纳了大量的基础设施，包括住宅、度假村综合体、酒店和道路。因此，人类对海岸变化的反应是用推土机推平海滩，抽沙，并为海岸装甲。这些活动对海岸上自然发生的过程有什么长期影响？这项研究旨在就全球屏障系统将如何应对海平面变化和缓解战略的变化提供指导方针，目的是确定最佳的社会反应，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进行沟通，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的培训，他们是下一代海岸研究人员，关于海岸过程的不同方面。