Meander dynamics in the mega-tidal salt marshes of the Mont Saint Michel Bay, France Seminar

Event details

The mega-tidal range of the Mont Saint Michel bay (up to 15 m) offers a unique opportunity to probe the controls on meander dynamics and channel migration in salt marshes: during spring tides, tidal channels experience flow conditions that are highly variable in just over a week. Using daily repeat terrestrial lidar surveys combined with new high accuracy processing techniques, a detailed picture of topographic change over the nearly complete meander surface can be obtained for various hydraulic conditions. This offers a natural experiment in which the response of elementary processes (e.g., point bar accretion, bank erosion...) to various hydrosedimentary forcings can be probed in situ. I will present the results of a 3 year study based on 37 repeat terrestrial lidar surveys combined with hydrosedimentary measurements (velocity, turbidity). This dataset offers new insights into the controls of pioneer vegetation on point bar accretion, flow hydraulics on bank erosion rates and the response of mega-tidal salt marshes to extreme tidal events.