Groundwater availability in south western Nigeria

In urban water supply the importance of groundwater has become very obvi­ous to most water supply agencies of the State Governments, thereby resulting in a tremendous increase in well drilling activities. This paper therefore provides a review of avai­lable groundwater information as well as the geological setting of South­western Nigeria. The degree of groun­dwater exploitation in each of the hydro-geological units in the study area is assessed in relation to their hydraulic characteristics. The results of the statistical analysis show that the behaviour of the borehole characteristics is erratic and unpredictable, and that generally the yields from the produ­ctive boreholes are very poor. The contribution of the geology of the area to this erratic behaviour and low yields is also discussed.