Groundwater Availability In Water Limited Regions of Africa

This study elucidates the potential of groundwater (GW) presence using Direct Current Electrical Resistivity method, in Gwagwalada, Abuja, Federal Capital Territory (FCT), Nigeria, an area located within the Sahel Savanah Ecological region, characterized by severe drought, consequently experiencing water shortage for the local population. Gwagwalada is one of the six major suburban areas that make up the FCT. The study area is located at latitude 8.961185^oN, longitude 7.089018^oE. The geology of the area is underlain by the Precambrian Basement Complex and Sedimentary Rocks. The age of the Basement Complex is Precambrian to Cambrian, and the rocks found in these regions consist of Metasediments, Granite porphyry, Diorites, Gneiss, Hornblende schist, and Migmatites. The objective of this study is to utilize electrical resistivity method to investigate potential presence of GW in this region. To achieve this objective, vertical electrical sounding and horizontal profiling were carried out. The data gathered from the survey area was analyzed using Surfer-8^©-software while the sounding data was analyzed with Zhody^© software.

Results show that areas with low resistivity values (high conductivity zones) have potentials for groundwater, in areas around profile one to six, west of the survey area. Low resistivity value is in the range of approximately 40 - 190 ohm/m. Interpretation of Vertical Electrical Sounding I and II shows that the potential groundwater zone (weathered/fractured basement) lies at a depth between 7 - 48 meters below ground level.

In conclusion, our findings indicate that the population in the FCT of Nigeria has approximately one million residents, and annual growth rate of 30%, due to relocation of the seat of government from Lagos to Abuja in 1991. There is a rising demand for water in the FCT area, stemming from subsequent population explosion. Therefore, GW source may be an avenue to meet this increasing demand.