ASSESSMENT OF WATER SUPPLY FROM STAND ALONE BOREHOLES IN BENIN METROPOLIS

ABSTRACT

The study area is about 170 km² in area extent and is underlain by the Benin formation and the soil is Miocene to Recent. The Benin formation dominantly consist of poorly consolidated sandstone with alternating thin sequences of clay and sandy clay soils.The mean annual precipitation in the study area is about 2260 mm and about 58% of this is given up as evapotranspiration. There is relatively high rate of infiltration in this area which is about 26% of the mean annual precipitation while the runoff constitutes about 16%.The hydraulic conductivity (E) values of the aquifer system indicate different values. The average layer groundwater velocity (V) is about 1.61 x 10² m/yr and the specific discharge is about 60 m/yr which is relatively high.

The study examines the Supply of water in Benin Metropolis from Stand Alone Boreholes in terms of its availability, distribution and accessibility to households. Stratified and systematic sampling techniques were employed in selecting residents for the study, through the use of questionnaires and oral interviews. Three local government areas were selected to a have a general idea of their access to water supply. The shortfall in water supply is attributed to a lack of maintenance and, mismanagement by appropriate authorities. The paper recommends a consistent monitoring of the population and spatial size of the city, increase in government funding and improved policies on social service provision, the standardized installation of long term water projects and the re-structuring and maintenance of existing facilities to meet the ever – increasing water demand by city residents.The soil profile analysis of the study area as shown in the groundwater level contour map of Benin City shows that the movement of the underground water is from North to South. With greater proportion of its reserve available at Ogba, Etete, and Avbriaria community in Oredo Local Government Area, while in Ikpoba-Okha Local Government Area, it is highly concentrated at Ikpoba Hill.