Geostatistical Correlation of Aquifer Potentials in Abia State, South-Eastern Nigeria

In this paper, a collection of statistical correlation methods is used in the study of aquifer potentials in Abia State of south-eastern Nigeria. The Physiology, geomorphology and hydrogeology of the area are first presented. Sixty-six Vertical Electrical Sounding (VES) data sets are used to determine the aquifer. Demographic studies are then carried out in 220 communities in order to determine the relationship between population size on one hand and a unit draw-down of wells due to groundwater abstraction on the other. The relationship between geological Formation, aquifer potentials and depth of boreholes are then calculated using Pearson’s correlation matrix. Results show that the mean population of persons appears to be higher in Bende-Ameki Formation (of Eocene-Oligocene age) and the late Tetiary-Early Quaternary Coastal Plain Sands, than in the Cretaceous shale Formation of Asata Nkporo. The mean population of persons sitting on these Formations is 31,200, 18,370 and 5400 respectively. Furthermore, it is observed that a population increase of about 50 persons in a community in Abia State is accompanied by a unit volume (1 m3) draw-down of wells due to groundwater abstraction. It is therefore concluded that population size is positively correlated with groundwater abstraction, aquifer potentials and geological Formation favouring aquifer in Abia State.

Reassessing Groundwater Potentials and Subsurface water Hydrochemistry in a Tropical Anambra Basin, Southeastern Nigeria

This review presented a detailed re-assessment of the hydrogeology and hydrochemistry of the Tropical Anambra Basin.It identified and discussed the major geological formations and their groundwater potentials.The geological examination showed that the Ajali Formation is confined in places forming an artesian condition;the potentials of this aquifer decline in the western basin due to a decrease in thickness.The sandstone associates of the Nsukka Formation are aquiferous and have produced high-pressure artesian boreholes along the Oji River.The Imo Shale is characterized by permeability stability all over much of the intermediate unit.The Bende-Ameki aquifer has a lesser amount of groundwater when equated to other formations;the geologic characteristics do not produce favorable hydrogeological conditions for groundwater occurrence.The stratigraphical and structural framework suggested the presence of an efficient throughflow in the basin.Based on physical and chemical parameters of water quality,the basin holds water of acceptable quality.While there are considerable investigations on the hydrogeology and hydrochemistry,studies are short of analysis of the hydrogeochemical evolution of groundwater,water quality index,heavy metals pollution index as well as total hazard quotient.Suitability of groundwater based on agricultural water quality indices(e.g.SAR)is also salient.Therefore,future studies should address these owing to increasing dependence on groundwater.