7. The Niger Delta Region

The Niger Delta is the largest in Africa and the third-largest in the world, with a total area of 112,106 km². The region has the largest freshwater swamp in Africa and is a biodiversity hot spot because of its rich variety of plant and animal species. This chapter describes geomorphological/geological units, with an emphasis on physiography, land cover characteristics and hydrocarbon pollution. The plains are homo-clinal geomorphic structures that trend westwards and south-westwards. This trend is broken in many places by small hogback ridges and shallow swamp basins, which abut at the coast against the sandy beach-ridge barriers lying between the tidal basins and the open sea. The gently undulating coastal lowland inland from this beach-ridge barrier zone has height ranges between 2.05 and 45 m above sea level. The geomorphological units of the region include the outer barrier island complexes adjoining the Atlantic Ocean, the lower tidal floodplain which consists of estuaries, mangroves, and creeks, and the upper freshwater riverine floodplain, within which seven ecological units are formed.