Coastal dynamics and geomorphology of the Pozos Colorados sector, Santa Marta: an analysis of sea level rise and paleo-shoreline

Abstract

Introduction: We assess how inherited subsurface architecture and human interventions control recent shoreline change and vulnerability in Pozos Colorados (Santa Marta, Colombian Caribbean). Methods: We integrated geomorphological mapping, multi-decadal shoreline extraction with CoastSat (1986–2024; EPR), Ground Penetrating Radar (GPR) profiles, paleoshoreline detection from high-resolution DEM, and paleo/future sea-level scenarios. Results: Net shoreline retreat averaged ~–2.0 m yr⁻¹ (max erosion in 1986–1996; localized accretion after 2021), linked to sediment budget shifts and engineering structures. GPR reveals erosional surfaces/terraces guiding present morphodynamics. Paleo sea-level highstands (MIS5e +6 m; mid-Holocene +3 m) and a 2100 SLR scenario overlap low-lying inherited surfaces. Discussion: Coupling surface (CoastSat) and subsurface (GPR) evidence clarifies multi-scale controls on instability and maps exposure hotspots, supporting ecosystem-based, adaptive coastal management in this urbanizing sector.