Newton Fund: Applying nature-based coastal defence to the world's largest urban area - from science to practice

基于自然的海岸防御解决方案越来越被认为是应对气候变化的传统硬工程方法的更可持续的替代方案。这些措施包括利用湿地、红树林、珊瑚礁和牡蛎礁作为缓冲区，可以减弱波浪，在海平面适度上升的情况下，这些区域的沉积物可以与海平面保持同步。湿地和红树林是存在更耐盐物种的区域，这可以保护它们后面的淡水物种。美国、荷兰和英国以及中国的一些地区都部署了基于自然的防御措施，并取得了不同程度的成功。在经历快速城市化的三角洲，应用基于自然的解决方案可能会导致与其他土地用途（例如土地复垦）的空间竞争。为了优化管理，必须解决基于自然的解决方案需要多少空间的问题。然而，我们目前对不同生态系统的规模依赖性防御价值和复原力的了解是不够的。此外，我们对海防生态系统创建所需的方法缺乏充分的了解，因为以前的恢复工作成功率很低。目前的提案旨在以世界上最大的城市地区--中国珠江三角洲（PRD）为模型系统，开发基于过程的理解和预测模型，以了解生态系统的规模要求，以及如何创建海防生态系统。将进行三角洲尺度的红树林区域监测和水动力建模，以研究最近的湿地面积变化，并在气候变化和土地开垦的对比情景下，估计生态系统空间的优化。这项大规模的研究还将为当地规模的实验和建模提供基础边界条件。一组实验将使用新的仪器进行，以提高我们的洞察力的过程中影响红树林的恢复力和繁殖。此外，亦会试验利用挖掘物料和蚝礁促进红树林生长的创新措施。当地规模的模型将结合新的实验知识来预测红树林的生物地貌动态，并为管理提供指导。开发的模型和知识将直接应用于与我们的项目合作伙伴合作建设的生态堤坝试点项目的设计。我们将考虑如何解决弹性城市规划和管理，通过优化土地利用，机构和机制，以实现更可持续的城市化，探索生态动态设计方案，为自然提供机会，将空间规划和灾害管理相结合，作为城市发展进程的一部分。英国申请人对项目的贡献摘要：英国申请人将领导工作任务1：湿地区域监测/流体动力学建模。这项工作将概述珠江三角洲的生物物理条件，包括现时及未来海平面和风暴气候预测下的地形和土地利用情况及其区域环境。英国研究小组将为珠江三角洲（珠三角）建立一个高分辨率非结构网格模式（FVCOM），用于水动力学研究，波浪和沉积物输运，这将为我们的荷兰和中国合作伙伴开展的大规模大气和海洋边界条件与小规模过程研究和生态系统建模之间提供接口。该模型与区域海平面预测一起，将用于为当地生态建模提供定量设想。

Project Summary:Nature-based coastal defence solutions have increasingly been recognized as more sustainable alternatives to conventional hard engineering approaches against climate change. These include using wetlands, mangroves, coral and oyster reefs as a buffer zone, which can attenuate waves and, in a regime of moderate sea level rise, the sediment trapping in such zones can keep pace with sea level. Wetlands and mangroves are regions in which more salt-tolerant species exist, which can protect freshwater species behind them. Nature-based defences have been deployed in the USA, Netherlands and UK and also in some parts of China, with varying degrees of success. In deltas undergoing fast urbanisation, applying nature-based solutions can lead to competition for space with other land uses, e.g.land-reclamation. For optimised management, the question of how much space is required by nature-based solutions must be addressed. However, our current knowledge of the size-dependent defence-value and resilience of different ecosystems is insufficient. Additionally, we lack full understanding of the methods needed for ecosystem creation for coastal defence, as previous restoration efforts have suffered low success rates.The current proposal aims to develop process-based understanding and predictive models of ecosystem size requirements and how to create ecosystems for coastal defence, using the world's largest urban area, the Pearl River Delta (PRD) in China, as a model system. Delta-scale mangrove area monitoring and hydrodynamic modelling will be conducted to study recent wetland area changes and estimate the optimisation of ecosystem spaces for defence, under contrasting scenarios of climate change and land-reclamation. This large-scaled study will also provide underpinning boundary conditions for local-scale experiments and modelling. A set of experiments using novel instruments will be conducted to improve our insights into the processes influencing mangrove resilience and propagation. Innovative measures of using dredged materials and oyster reefs to facilitate mangrove establishment will also be tested experimentally. Local-scale models will incorporate the new experimental knowledge to predict mangrove bio-geomorphic dynamics and provide guidelines for management.The developed models and knowledge will be directly applied in the design of a pilot eco-dike project due to be constructed, in collaboration with our project partners. We will consider how to address resilient urban planning and management, in terms of combining spatial planning and disaster management by optimising land use, institutions and mechanisms for more sustainable urbanisation, exploring eco-dynamic design options to provide opportunities for nature as part of the urban development processes. Summary of the UK applicants' contribution to the project:The UK applicants will lead Work Task 1: Wetland area monitoring/hydrodynamic modelling. This work task will provide an over-view of the bio-physical conditions, including the morphological and land-use aspects of the PRD and its regional setting, for the present day, and under future climate projections of sea level and storms.The UK team will implement a high resolution unstructured-grid model (FVCOM) for the Pearl River Delta (PRD) for hydrodynamics, waves and sediment transport which will provide the interface between the larger scale atmospheric and oceanic boundary conditions and the smaller-scale process studies and ecosystem modelling to be carried out by our Dutch and Chinese partners. This model, together with regional sea level projections, will be used to provide quantitative scenarios for the local area ecological modelling.