Assessment of viability of exploiting artesian aquifers for municipal water supply in parts of south-east Nigeria using isotope techniques

The steady growth in Nigeria's population, now about 140 million, and the continuing relocation of many citizens from rural to urban areas in pursuit of higher education and employment opportunities have placed considerable stress on social infrastructures particularly water supply in most of the state capitals. In parts of the Middle Belt and South East, artesian flows have been encountered in boreholes tapping the False bedded Ajali Sandstone and Upper Coal Measures geological formations. The IAEA sponsored TC Project No. NIR/8/007: 'Isotope-based Investigation of Groundwater in the Middle-Belt and South East' seeks to evaluate the source, recharge and hydrochemistry of these artesian aquifers through study of their hydro-geological setting, hydraulic and hydro-chemical parameters and isotopic compositions of the source water. An inventory of most of the existing artesian boreholes has been completed. Thirty-three (33) water samples have been collected from surface and groundwater sources including artesian and non-artesian boreholes at varying depths, for isotopic and hydrochemical analysis, which results, when available would lie interpreted and discussed in a subsequent paper. This paper reviews the hydro-geology of the project area and outlines the way the project would progress with emphasis on the role isotope hydrology would play in resolving the sustainability question associated with exploitation of the artesian aquifers for municipal water supply schemes. It is envisaged that integrated interpretation of isotopic and hydrochemical data to be acquired together with baseline data would provide informed advice to water resources managers and decision-makers on the viability of planning large scale water supply schemes based on these artesian aquifers. (author)