Coastal SEES Collaborative Research: Morphologic, Socioeconomic, and Engineering Sustainability of Massively Anthropic Coastal Deltas: the Compelling Case of the Huanghe Delta

由于其非凡的自然资源和生态系统服务，河流三角洲海岸线为全世界数亿人提供了家园。然而，社会对三角洲景观的可持续性是不确定的，因为人类的重大影响包括：1)由于河道筑坝和筑堤，沉积物（任何三角洲系统维持生命的资源）减少；2)破坏河流三角洲海岸线内和沿岸的自然沉积物扩散和沉积模式；3)由于地下水和化石燃料开采，低洼的三角洲景观加速下沉；4)海平面上升，有可能淹没三角洲景观。该项目的总体目标是通过将研究三角洲增长的物理方面与社会经济决策相结合的科学来评估河流三角洲的可持续性。这项研究将为脆弱的三角洲资源的可持续利用提供指导，同时促进最佳工程实践，保护社会和基础设施免受河流洪水、海洋风暴和海平面上升等灾害的影响。其他更广泛的影响包括培训沿海可持续发展跨学科领域的未来学者，创建基于互联网的界面以促进沿海可持续发展的全球公民意识，以及为休斯敦和洛杉矶代表性不足的群体开发沿海科学和可持续发展高中课程的教学模块和补充讲习班。该项目是美国国家科学基金会海岸科学、工程和教育可持续发展项目的一部分。建设可持续三角洲海岸线的关键资源是泥沙，而控制泥沙输运的关键因素是河道的冲刷、河道相对快速的位移和新河道的形成。一个由多名研究者组成的跨学科研究小组将解决以下对河流三角洲沿海可持续性具有根本重要性的问题：在高度利用的三角洲上改变河道路径的社会经济后果是什么？当前的三角洲土地流失缓解战略在长期（几十年到几百年）的时间尺度上是否可持续？能否预测未来重大洪水事件的地点？这些问题将以中国黄河三角洲为例进行研究。黄河三角洲是一个引人注目的地区，因为它是世界上最具活力和高度城市化的沿海景观之一。黄河三角洲的经验教训将用于评估全球三角洲海岸线的可持续性。该项目将建立海岸可持续性的预测模型，将三角洲的崩裂机制、相关的河道-海岸线相互作用、自然和工程崩裂的社会经济反应以及由此产生的人-自然耦合系统动力学结合起来。美国研究人员将与中国同行合作，创建一个多学科沿海可持续性研究的模板，以帮助指导未来的治理和决策，将人类三角洲动态、社会目标和不确定性、灾害和土地利用工程、沿海形态动力学和教育推广结合起来。该项目将评估在沉积物供应减少和海平面上升的情况下，是否可以利用工程侵蚀来管理大规模人为海岸景观，以最大限度地减少海岸侵蚀。

Owing to their extraordinary natural resources and ecosystem services, river-delta coastlines host hundreds of millions of people worldwide. However, the sustainability of society on delta landscapes is uncertain, due to significant human influences including: 1) reduction of sediment - the life sustaining resource for any delta system - as a result of damming and leveeing of river channels, 2) disrupting natural sediment dispersal and deposition patterns within and along river-delta coastlines, 3) accelerated sinking of low-lying deltaic landscapes due to sub-surface water and fossil fuel extraction, and 4) sea-level rise, which threatens to drown deltaic landscapes. The overarching goal of this project is to evaluate river-delta sustainability by merging science that examines physical aspects of delta growth with socio-economic decisions. This research will provide guidance for the sustainable use of vulnerable delta resources, while promoting best engineering practices that protect society and infrastructure from disasters including river flooding, ocean storms, and sea-level rise. Additional broader impacts include training future scholars for the interdisciplinary field of coastal sustainability, creating an internet-based interface to promote global-citizen awareness in coastal sustainability, and developing teaching modules with complementary workshops intended for high-school courses on coastal science and sustainability for underrepresented groups in Houston and Los Angeles. This project is supported as part of the National Science Foundation's Coastal Science, Engineering, and Education for Sustainability program - Coastal SEES.The crucial resource in building sustainable deltaic coastlines is sediment, and the key control on sediment delivery is river channel avulsions, relatively rapid displacements of river channels and the formation of new river channels. A multi-investigator, cross disciplinary team of researchers will address the following questions of fundamental importance to river-delta coastal sustainability: What are the socioeconomic consequences of altering river channel pathways on a highly utilized delta? Are current delta land loss mitigation strategies sustainable over long-range (decades to centuries) timescales? Can the location of significant future flooding events be predicted? These questions will be addressed using the Huanghe (Yellow River) delta, China as a case study. The Huanghe delta is a compelling region because it is one of the most dynamic and heavily urbanized coastal landscapes in the world. Lessons learned from the Huanghe delta will be exportable to evaluate the sustainability of delta coastlines worldwide. This project will build predictive models for coastal sustainability by bringing together the mechanics of avulsion on deltas, associated channel-shoreline interaction, socio-economic response to natural and engineered avulsions, and the resulting coupled human-natural system dynamics. U.S. researchers in cooperation with Chinese colleagues will create a template for multi-disciplinary coastal sustainability research to help guide future governance and decision making that integrates human-delta dynamics, societal objectives and uncertainty, hazard and land use engineering, coastal morphodynamics, and educational outreach. This project will evaluate whether massively anthropic coastal landscapes can be managed using engineered avulsions to minimize coastal erosion in the face of reduced sediment supply and rising sea level.