OS009-0006
Future Interactions Between Sea Level Rise, Tides and Storm Surges in the Pearl River Delta
Future Interactions Between Sea Level Rise, Tides and Storm Surges in the Pearl River Delta
Tuesday, 8 December 2020
Poster
Abstract:
The Pearl River Delta (China) is the largest urban agglomeration in the world but is located in a low-lying, flood-prone coastal environment. This study is the first to address how future sea level rise, tides and typhoon storm surges will interact in the Pearl River Delta under several future mean water level scenarios.
We used an FVCOM (Finite Volume Community Ocean Model) implementation for the South China Sea and the Pearl River Delta to explore how the mean sea level rise signal coming from the open ocean interacts with coastal processes, and whether tidal range and mean high water also increase with sea level rise. Additionally, we studied how the surges generated by the two most recent and strongest typhoons that impacted the Pearl River Delta, Typhoon Hato (2017) and Typhoon Mangkhhut (2018), would change under future sea level conditions. We examined four future sea level rise scenarios: 0.3, 0.5, 0.9, and 2.1 m, which encompass the broad range of climate-scenario-based sea level projections making the results applicable across time horizons.
We found that in delta environments sea level rise is not simply added to extreme water levels, but induces feedbacks on tides and surge levels. Amplification of tides exceeds 0.5 m for 2.1 m sea level rise. Thus, the simple approach of just increasing the height of coastal defences by the amount of the regional projected sea level rise might not be sufficient in this area. On the other hand, if typhoons like Hato or Mangkhut were to happen in the future, a surge level reduction up to 0.5 m could be expected in coastal areas. Our final aim is to use the Pearl River Delta FVCOM model and the future coastal flooding scenarios to understand if ecosystem-based coastal defence solutions (mangroves) are a viable solution against sea level rise, tides and extreme storm surges.
We used an FVCOM (Finite Volume Community Ocean Model) implementation for the South China Sea and the Pearl River Delta to explore how the mean sea level rise signal coming from the open ocean interacts with coastal processes, and whether tidal range and mean high water also increase with sea level rise. Additionally, we studied how the surges generated by the two most recent and strongest typhoons that impacted the Pearl River Delta, Typhoon Hato (2017) and Typhoon Mangkhhut (2018), would change under future sea level conditions. We examined four future sea level rise scenarios: 0.3, 0.5, 0.9, and 2.1 m, which encompass the broad range of climate-scenario-based sea level projections making the results applicable across time horizons.
We found that in delta environments sea level rise is not simply added to extreme water levels, but induces feedbacks on tides and surge levels. Amplification of tides exceeds 0.5 m for 2.1 m sea level rise. Thus, the simple approach of just increasing the height of coastal defences by the amount of the regional projected sea level rise might not be sufficient in this area. On the other hand, if typhoons like Hato or Mangkhut were to happen in the future, a surge level reduction up to 0.5 m could be expected in coastal areas. Our final aim is to use the Pearl River Delta FVCOM model and the future coastal flooding scenarios to understand if ecosystem-based coastal defence solutions (mangroves) are a viable solution against sea level rise, tides and extreme storm surges.