Decadal beach-dune profile monitoring along a 230-km high-energy sandy coast: Aquitaine, southwest France

Large-scale coastal monitoring programs are challenging to maintain over time but necessary understand and further predict complex evolution resilience. The 230 km-long Aquitaine coast is a high-energy meso-macrotidal composed of beach-dune systems showing dramatic morphological changes at seasonal interannual scales. This study investigates the alongshore variability in response based on unique 11-year dataset 41 spaced transects surveyed yearly spring. completed by interspersed autumn LiDAR surveys for analysis. Several descriptors developed, such as volume, beach width different shoreline proxies delimiting intertidal zone, face dune face. system characterised north-south gradient, from chronically eroding dunes backing low-elevation dissipative beaches north, slowly accreting wide south, through range intermediate states. Time- spatially-averaged (dune foot position) trend ?0.5 m/year (erosion), with local variations ranging ?5.9 +2.1 m/year. During 2013–2014 winter widespread erosion was observed, 13 m 8 average along Gironde Landes coasts, respectively. provides insight into timing, magnitude spatial recovery outstandingly erosive winter. We also show that volume good proxy long-term trend. It advocated large-scale means single profiles distributed 10–100 km cheap efficient approach address regional scale, which can bring complementary information aerial photographs interpretation determine thus contribute support sustainable management planning.