Unraveling the decadal-scale coastal evolution and hazards of the Salamanca Barrier (Colombia)

This study aims to characterize the primary coastal hazards operating at both medium-term and episodic scales along the Salamanca barrier in the Caribbean coast of Colombia. On a medium-term (decadal) scale, we analyzed satellite images spanning the past 40 years to characterize shoreline evolution, the associated coastal sediment budget and the responsible sediment transport pattern. At this scale, the barrier has experienced intense shoreline retreat, with erosion rates gradually decreasing over time. For the last analyzed period, 2009-2019, maximum erosion rates have exceeded -20 m/yr. This erosion is primarily driven by a net longshore sediment transport pattern directed towards the west, induced by a wave climate concentrated in a narrow direction arc from the NE. Peak transport rates, reaching an order of magnitude of 106 m3/yr, have been estimated for the westernmost (more exposed) part of the barrier. At an episodic scale, we estimated hazards by evaluating storminduced erosion and flooding potential. The eastern zone of the barrier showed greater susceptibility to overwash, while potential erosion was only relevant in the western and central sectors. Notably, the most impactful events were associated with waves from directions of 30 and 40 degrees. The cumulative contribution of hazards operating at both scales contribute to various challenges affecting infrastructures, ecosystems, and communities along the Salamanca barrier.