Aller au contenu. | Aller à la navigation

Laboratoire d’Etudes en Géophysique et Océanographie Spatiales

Outils personnels

This is SunRain Plone Theme

Navigation

Vous êtes ici : Accueil / Actualités / Séminaires / Seminaires Septembre 2017-Aout 2018 / Lundi 20 novembre - O. Dada - Trends of Niger Delta Shoreline in the last 100 years

Lundi 20 novembre - O. Dada - Trends of Niger Delta Shoreline in the last 100 years

Par SEMSOU Dernière modification 09/10/2017 17:27
Quand ? Le 20/11/2017,
de 11:00 à 12:00
Où ? Salle Coriolis
Participants Olusegun A. Dada, Federal University of Technology, Akure, Nigeria
Ajouter un événement au calendrier vCal
iCal


Olusegun Dada,

Department of Marine Science and Technology

Federal University of Technology, Akure, Nigeria

 

 

Title :Trends of Niger Delta Shoreline in the last 100 years

 

Abstract :

Deltaic coasts are dynamic geomorphic systems where continuous changes occur on diverse spatial and temporal scales, and these changes constitute an important aspect of their evolution. More important, they host critical economic infrastructures and diverse ecosystems as well as high concentrations of human population. However, they are highly vulnerable to the effects of global climate change and human interference which necessitate their continual monitoring for sustainable management.

This paper investigates trends of shoreline along the Niger Delta coast of the Gulf of Guinea, North Atlantic Ocean in the last ten decades (1923-2013) by means of topographic maps and satellite imagery in GIS environment. Further, in other to understand processes governing the multi-decadal shoreline changes in this wave-dominated delta re-analyzed wave data coupled with hydro-meteorological data were analyzed.

Findings reveal two distinct shoreline dynamics patterns/phases: first, mobility with high net retreat between 1923 and 1987 interval and; second, mobility with low net progradation from 1987 to 2013. During the first phase, shoreline retreat is mainly concentrated on the western and arcuate sections of the delta. In the second phase, all sections of the Niger Delta coast prograded seaward.

Rainfall and river discharge variations are consistent with shoreline change results: there is downward trend in river discharge between 1923 and 1987, and significant upward trend after 1987. Multivariate regression analysis show that interannual wave regime as well as mean longshore sediment transport rate are higher in the last three decades (1980-2013) than over the last 80 years (1900-1980) along this coast. This implies that high net pre-1987 (1923-1987) shoreline retreat shoreline of the delta is most likely influenced by weakening of river (water and sediment) discharges due to changing climate and human interference.

However, the paper concludes that changing wave regime and associated littoral transport off the Niger Delta acting in concomitant with fluvial discharge variability constitute a powerful and effective mechanism responsible for much of the Niger Delta shoreline changes.

Actions sur le document