A preliminary analysis of regional groundwater movement in the Niger Delta, Nigeria

A preliminary analysis of regional groundwater movement has been done for the Niger Delta, Nigeria. The Niger Delta covers an area of about 75,000 km² in southern Nigeria. The Delta is underlain by clastic Tertiary sediments, from top to bottom: the Benin, Agbada, and Akata Formations. The Delta is one of the most hydrocarbon rich regions in the world, where petroleum has been produced from the Agbada Formation by several oil companies. Oil and gas production has resulted in environmental degradation of the delta. In this study, a preliminary analysis of groundwater movement in the delta is performed to determine groundwater flow pathways, discharge and recharge areas, and average residence time of water movement through the flow systems. The USGS three-dimensional finite-difference code, MODFLOW, was used to simulate steady-state flow. No regional flow system occurred, and flow was concentrated in intermediate and local systems. A major discharge area was found that collects water from local flow systems in the coastal plains and from intermediate systems that originate from the mid topographic elevations. The depth to length ratio of the Niger Delta, its low regional slope, and its significantly undulating surface relief make the delta a hydrogeologically shallow basin.