RenovRisk – Transfers Project: Numerical modelling of floods on the ravines of western Reunion Island

Due to its geographical position, Reunion Island is regularly affected by tropical cyclones (or other rain events with high intensities and cumulative rainfall). These episodes of extreme rain and wind lead to rapid and very intense floods, and their economic damage and associated human losses can be very significant. In a general context of climate change, several factors appear to indicate an increased sensitivity of the Reunion Island to the risk of tropical cyclones (widening of the tropical belt, migration towards the poles of the cyclonic intensity maxima, rise in sea temperature which could increase energy available for cyclones).

The RenovRisk – Transfers project aims to study these natural risks associated with cyclones and which affect the territory of the Reunion Island. It will focus in particular on the area of ​​the Maïdo Massif, located in the west of the island. The ravines of this massif are fed by cyclones and their hydrological behaviour is still poorly understood, despite the extreme risks of flash and coastal floods.

Study area (Left); Watersheds associated with three hydrometric stations in the ravines of Bernica and Saint-Gilles (Right)

This project is organized into four main actions:

  • Action 1 aims to enhance our understanding of atmospheric hazards, with, in particular, a fine mapping of rainfall and a mapping of ecological and economic risks related to wind.
  • Action 2 will study the hydrological hazards, by implementing flood modelling tools.
  • Action 3 will describe the coastal hazards.
  • Action 4 will focus on the database produced during the project and will ensure their scientific dissemination.

The HYDRO team is particularly involved in action 2 on hydrological risks. Its two main objectives are:

  1. Development of hydrological simulation models on a spatio-temporal fine scale
  2. Exploratory work on real-time anticipation of extreme floods

Funding: FEDER-Réunion

Coordinator: OSU-Réunion

Partners: OSU-Réunion, Météo-France, INRAE Antony

Duration: 2019 – 2021

Contact @ INRAE: Gaia Piazzi & Charles Perrin