A monitoring network for assessing the impact of extreme marine meteorological events on tropical beaches

International audience Since 2003, a monitoring network of the dynamics of sandy beaches has been in operation in three tropical sites:Martinique (French West Indies), Tahiti and Moorea (French Polynesia) and Mayotte (Mozambique Channel).The objective of this network is to measure the impact of extreme weather-related marine events (storms,cyclones, strong swells, surges...) on beaches with varied structural settings and sedimentary environments. Themethodology consists in the installation of observatories on the dynamics of sandy beaches in differentmorphological and sedimentary contexts. A “state zero” is established from a combination of satellite imagery,low altitude digital imagery and topographic and hydrodynamic measurements. These measurements arereiterated after an extreme event in order to apprehend the importance of morphological change, impactdampening and recovery. The monitoring is then continued over regular intervals with the aim of determiningrates of morphological and sediment budget recovery until equilibrium is restored.This experimental network design will subsequently be extended to other tropical beaches located on thepropagation paths of cyclones.