Institute of Marine Sciences, University of California, 115 McAllister Road, Santa Cruz, CA 95060, USA; The Nature Conservancy, 115 McAllister Road, Santa Cruz, CA 95060, USA.
The Nature Conservancy, 115 McAllister Road, Santa Cruz, CA 95060, USA; Institute of Marine Sciences, University of California, 115 McAllister Road, Santa Cruz, CA 95060, USA.
J Environ Manage. 2018 Mar 15;210:146-161. doi: 10.1016/j.jenvman.2018.01.024.
Coastal communities in tropical environments are at increasing risk from both environmental degradation and climate change and require urgent local adaptation action. Evidences show coral reefs play a critical role in wave attenuation but relatively little direct connection has been drawn between these effects and impacts on shorelines. Reefs are rarely assessed for their coastal protection service and thus not managed for their infrastructure benefits, while widespread damage and degradation continues. This paper presents a systematic approach to assess the protective role of coral reefs and to examine solutions based on the reef's influence on wave propagation patterns. Portions of the shoreline of Grenville Bay, Grenada, have seen acute shoreline erosion and coastal flooding. This paper (i) analyzes the historical changes in the shoreline and the local marine, (ii) assess the role of coral reefs in shoreline positioning through a shoreline equilibrium model first applied to coral reef environments, and (iii) design and begin implementation of a reef-based solution to reduce erosion and flooding. Coastline changes in the bay over the past 6 decades are analyzed from bathymetry and benthic surveys, historical imagery, historical wave and sea level data and modeling of wave dynamics. The analysis shows that, at present, the healthy and well-developed coral reefs system in the southern bay keeps the shoreline in equilibrium and stable, whereas reef degradation in the northern bay is linked with severe coastal erosion. A comparison of wave energy modeling for past bathymetry indicates that degradation of the coral reefs better explains erosion than changes in climate and historical sea level rise. Using this knowledge on how reefs affect the hydrodynamics, a reef restoration solution is designed and studied to ameliorate the coastal erosion and flooding. A characteristic design provides a modular design that can meet specific engineering, ecological and implementation criteria. Four pilot units were implemented in 2015 and are currently being field-tested. This paper presents one of the few existing examples available to date of a reef restoration project designed and engineered to deliver risk reduction benefits. The case study shows how engineering and ecology can work together in community-based adaptation. Our findings are particularly important for Small Island States on the front lines of climate change, who have the most to gain from protecting and managing coral reefs as coastal infrastructure.
热带环境下的沿海社区面临着环境退化和气候变化带来的日益增加的风险，需要采取紧急的地方适应行动。有证据表明，珊瑚礁在减缓波浪方面起着至关重要的作用，但这些影响与海岸线的影响之间的直接联系相对较少。珊瑚礁很少被评估其海岸保护服务，因此也没有因其基础设施效益而得到管理，而广泛的破坏和退化仍在继续。本文提出了一种系统的方法来评估珊瑚礁的保护作用，并根据珊瑚礁对波浪传播模式的影响来研究解决方案。格林纳达格伦维尔湾的部分海岸线遭受了严重的海岸侵蚀和沿海洪灾。本文(i) 分析了过去 60 年来该海岸线和当地海洋的历史变化，(ii) 通过首次应用于珊瑚礁环境的海岸线平衡模型评估了珊瑚礁在海岸线定位中的作用，以及 (iii) 设计并开始实施基于珊瑚礁的解决方案，以减少侵蚀和洪水。通过水深测量和底栖调查、历史图像、历史波浪和海平面数据以及波浪动力学建模，分析了过去 60 年来海湾的海岸线变化。分析表明，目前，南部海湾健康发达的珊瑚礁系统使海岸线保持平衡和稳定，而北部海湾的珊瑚礁退化与严重的海岸侵蚀有关。过去水深模型的波浪能量模拟比较表明，珊瑚礁的退化比气候变化和历史海平面上升更能解释侵蚀。利用珊瑚礁如何影响水动力的这一知识，设计并研究了一种珊瑚礁恢复解决方案，以改善海岸侵蚀和洪水。一个典型的设计提供了一个模块化的设计，可以满足特定的工程、生态和实施标准。2015 年实施了四个试点单位，目前正在进行实地测试。本文介绍了迄今为止为数不多的现有珊瑚礁恢复项目设计和工程实例之一，旨在提供降低风险的好处。该案例研究展示了工程学和生态学如何在基于社区的适应中共同发挥作用。我们的研究结果对于处于气候变化前线的小岛屿国家尤其重要，这些国家从保护和管理珊瑚礁作为沿海基础设施方面获益最多。
