Applying nature-based coastal defence to the world's largest urban area

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 project includes teams from the Netherlands, UK and China. The UK team (from NOC and the University of Liverpool) include: Dr Judith Wolf (UK PI), Dr Sveta Jevrejeva (co-I), Dr Ming Li (co-I), Dr Michela De Dominicis and Dr Peng Zheng. The Dutch team is led by Dr Tjeerd Bouma of the Royal Netherlands Institute for Sea Research (NIOZ) and the Chinese team is led by Dr Zhan Hu of the Sun Yat-sen University (SYSU).

The UK team leads Work Task 1 on wetland area monitoring and 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.