Recent Niger Delta shoreline response to Niger River hydrology: Conflict between forces of Nature and Humans

Abstract

The Niger River Delta is a prolific hydrocarbon province and a mega-delta of economic and environmental relevance. To understand patterns of its recent shoreline evolution (1923–2013) in response to the Niger River hydrology, and establish the role played by forces of Nature and Human, available topographic and satellite remote sensing data, combined with hydro-climatic (rainfall and runoff) data were analyzed.Results indicate that the entire delta coastline dramatically receded: 82% of the >400 km-long coast retreated, during the period 1950–1987; and 69% between 2007 and 2012. Prior to 1950, there was a continuation of seaward advancement along 53–74% of the delta coast. The 1950–1987 shoreline recession coincided with occurrences of two major events in the Niger River basin; these are downward trends in hydro-climatic conditions (the great droughts of the 1970s-1980s), and dam construction on the Lower Niger River at Kainji (1964–1968). The 2007–2012 event corresponded with the extensive channel dredging during 2009–2012 in the Lower Niger River from the coastal town of Warri in the south to Baro in the north. Remarkably, the largest net shoreline advancement recorded in 74% of the entire delta area occurred within a year (2012–2013), which we link to increased sediment supply to the coast caused by the ‘2012’ floods, adjudged the worst floods in the entire Niger River Basin in the last few decades. With both anthropogenic and environmental factors inducing delta evolution, only innovative river and coastal management can determine the fortune of the future coastal development of the Niger Delta.