Drivers of Coastal Morphodynamics on a Deltaic Barrier  in the Colombian Caribbean

Gómez, Juan Felipe

Drivers of Coastal Morphodynamics on a Deltaic Barrier in the Colombian Caribbean

dc.contributor.author	Gómez, Juan Felipe
dc.contributor.supervisor	Kwoll, Eva
dc.contributor.supervisor	Walker, Ian J.
dc.date.accessioned	2024-03-28T18:16:06Z
dc.date.available	2024-03-28T18:16:06Z
dc.date.issued	2024
dc.degree.department	Department of Geography
dc.degree.level	Doctor of Philosophy PhD
dc.description.abstract	This research presents results from a series of analyses focussed on the overarching goal of identifying and understanding drivers of coastal morphodynamics on a deltaic barrier in the Colombian Caribbean coast, eastward from the Magdalena River mouth. Forcing mechanisms operating at different temporal scales were considered, including the influence of vertical land motion (VLM), storms, river discharge, trade winds, and wave conditions. These forcing mechanisms were related to geomorphic changes determined from satellite imagery taken before and after specific events. Satellite imagery and synthetic aperture radar acquisitions were used to assess decadal-scale coastline changes and VLM for the period 2007–2021. The findings revealed that VLM rates are highly variable alongshore, and that subsidence occurs mainly landward of highly erosive stretches of coastline associated with former mangrove forest. Drivers of coastal morphodynamics operating on time spans from days to seasons were assessed by focusing on four lagoons located along the back-barrier to better understand the interplay between extreme events and the breaching and healing of inlets that are temporarily formed between the lagoons and the ocean. Satellite data in conjunction with hourly readings from weather stations spanning the past 50 years helped to determine the conditions that enabled the breaching and healing processes to transpire in the lagoons. Aligned with the predominantly erosive regime along the study area, the findings indicated that the cumulative effect of the breaching and healing of the lagoons resulted in a deltaic barrier that has rolled over the lagoons, modifying their size over time. The occurrence of meteotsunamis and their role in coastal morphodynamics was investigated using a wavelet analysis applied to water-level readings in three tide gauges for the period 2013–2022. After the discovery of one event with meteotsunami-like characteristics, the atmospheric conditions and total water levels associated with this event were analyzed. The results indicated that total water levels related to the meteotsunami are similar to those produced by moderate storms and both phenomena can induce breaching of lagoons. To date, the barrier has responded to external forcers through a landward displacement of the coastline driven by cycles of lagoon breaching and healing as well as overwashes on lagoons, wetlands, and beaches. Seasonal storms have been critical in forcing these processes and have substantially influenced the barrier evolution during the last 50 years. Taken as a whole, this body of work provides knowledge about the response of deltaic barriers to geomorphologic forcers based on a study area in an understudied region of the Caribbean. At a regional level, the findings are relevant for science-based coastal planning and managing policies. Moreover, this research used a variety of methodological approaches to track causality on coastal landscapes in a manner that can be replicated in other areas with limited pre-existing information and without ongoing monitoring programs.
dc.description.scholarlevel	Graduate
dc.identifier.bibliographicCitation	Gómez, J.F., Kwoll, E., Walker, I.J., Shirzaei, M., 2021. Vertical Land Motion as a Driver of Coastline Changes on a Deltaic System in the Colombian Caribbean. Geosciences 11, 300. https://doi.org/10.3390/geosciences11070300
dc.identifier.bibliographicCitation	Gómez, J.F., Kwoll, E., Walker, I.J., Orejarena, A.F., 2023. Examining the Hydro-Climatic Drivers of Lagoon Breaching and Healing in a Deltaic Barrier. Geosciences 13, 118. https://doi.org/10.3390/geosciences13040118
dc.identifier.uri	https://hdl.handle.net/1828/16328
dc.language	English	eng
dc.language.iso	en
dc.rights	Available to the World Wide Web
dc.subject	delta
dc.subject	coastal morphodynamics
dc.subject	coastal change
dc.subject	sea-level rise
dc.subject	subsidence
dc.subject	lagoon
dc.subject	meteotsunami
dc.subject	erosion
dc.subject	spatio-temporal scales
dc.subject	Magdalena River
dc.title	Drivers of Coastal Morphodynamics on a Deltaic Barrier in the Colombian Caribbean
dc.type	Thesis