Subsidence in River Estuaries in France

Context

The relationship between river estuaries and the built-up environment surrounding them is gaining recognition in light of predicted climate change impacts on sea level and subsidence of urban areas. The case of the Thames river estuary demonstrates how sea level rise in combination with land subsidence and physical encroachment can contribute to elevated risk to physical assets and infrastructure in a river basin. Initiated in 2002, the Thames River Estuary Project (TE2100) continues to work to evaluate the potential impact of climate change on the Thames River floodplain, including the greater London area. This project has identified significant potential impacts which could affect more than 1.25 million people. It also provided a platform upon which to create a preparedness plan and guided development decisions with regard to flood preparedness.

EO Contribution

The purpose of the EOEuropa project is to provide input for similar studies of European river estuaries, where EIB has invested in infrastructures (e.g. port facilities). The project aims to identify and characterise the historical deformation of the ground around the Gironde and Loire estuaries in France, where the main deformation phenomena are coastal lowland subsidence. The deformation of flood defense infrastructure will also be studied, as well as carrying out comparisons with historical events (e.g. floods) and an analysis of the correlation with human activities in the areas.

The terrain motion products are derived using the Persistent Scatterers Interferometric (PSI) technique and contain point-wise information of vertical displacement rates with an accuracy better than a few mm/year.