Abstract

Ukani D. Jackson, Ovarere N. Gabriel and Ogunagbe Francis Brorhie

Some hydrogeological parameters of Umuahia South Local Government Area of Abia State, Nigeria, were studied to provide data for proper planning and execution of water projects in the area. Boreholes tap water from Miocene to Recent Benin Formation in the study area. This Formation is characterized by a multi-aquifer system in most places where it outcrops. Two aquifers were identified from lithologic logs in the study area within this Formation. These are the upper unconfined to confined aquifer between 30-60 meters depth, and an underlying confined aquifer between 80-160 meters depth. Static Water Levels are low and lie in the range of 28.3 -39.6 meters, while hydraulic heads vary from 80.3 to 127 meters. Hydrochemical studies show that groundwater in the area is low in dissolved constituents. However, iron requires treatment at some locations, while all the water samples should be treated for acidity. The hydrochemical facies identified include Na-K-HCO3-Cl facies and Ca-Mg-HCO3-Cl facies, with the former dominating. The ions in the water owe their source from geology and precipitation, while variation in the data can be explained by the exploitation of water from different aquiferous levels