EVALUATION OF AQUIFER HYDRAULIC PROPERTIES FROM RESISTIVITY AND PUMPING TEST DATA IN PARTS OF GWAGWALADA, NORTHCENTRAL NIGERIA

Abstract

Population upsurge in Gwagwalada increased water demand in the area, thereby stressing water resources in the area. Aquifer properties in parts of Gwagwalada in North-Central Nigeria were therefore investigated using surface geological mapping data combined with resistivity and pumping test data. The geological mapping revealed that the study area is underlain by granite-gneiss. The joint direction measurements showed two conspicuous joint directions namely the major NE-SW direction followed by the SE-NW direction. Static water level measurements of hand dug wells were used to determine the groundwater flow direction for the area which coincides with the NE-SW joint direction. Ten VES was carried out on the area. The geoelectric sections revealed 4 to 5 layers and the longitudinal conductance varied from 0.11 Ohm-1 to 0.37 Ohm-1. Constant rate pumping test was adopted for the research and 10 boreholes were pumped test. Static water level, discharge rate and drawdown range respectively from 1.2 m to 19.4 m, 82.08 m3/d to 319.68 m3/d and 6.57 m to 84.6 m. The weathered/fractured basement range from 7.5 m to 56.7 m. The transmissivity values in the area ranged from 0.35 m²/day to 3.63 m²/day while the hydraulic conductivity range from 0.045 m/day to 0.18 m/day. The investigation results revealed areas with low and moderate groundwater potential, as well as areas with weak and moderate aquifer protective capacity. The efficacy of resistivity and pumping test data in quantifying aquifer properties has been established in this research. It is recommended that a qualitative analysis of this water be carried out in view of water demand analysis in Gwagwalada for a proper planning and management of water resources.