Hydraulic Properties of Abakaliki Shale-Regolith Aquifer, In Ebonyi State South Eastern Nigeria

Abstract

This work aims at calculating the hydraulic properties of the Abakaliki shale-regolith aquifer which provides water to Abakaliki Metroplex via shallow wells on the basis of pumping test data, geoelectrics and joints density analysis.

Results  from pumping test analyses show that the highest value of hydraulic conductivity K for the shales occurs in Ndu-Otara Ebie Unuhu(0.417m²/s) while the lowest value is  0.132m²/s in Ochobo. Also with this method transmissivity varies from 7.97m²/day at Obusia Amechi to 1.59m²/day at Ochobo while the storativity ranges between 6.98 x  at Abulechi Agbaja to 7.35 x at the Rice Mill . Results from joint density analysis show that lowest value of K occur at Nwafor Ogu (2.12m/²day) while the highest value was obtained at Ochobo (6.35m²/day). Also using joint density measurements, the highest value of T, 7.05×10²m/day was obtained at Ochobo while the lowest value of 2.3 ×10¯³m²/day was found at Nwafor Ogu. Values obtained from geoelectrical method show that the highest K value occur at Amanata was 17.49x m²/s while the lowest value occur at Achara Unuhu is 0.106 x m²/s.    Highest T value of 109.3m/day  occur at Obusia Amaechi while the lowest value of 3.26m/day occur at  Simon Okpo . The average value of transmissivity (T) using the three methods was found to be 4.85m²/day. Also the average values of storativity and hydraulic conductivity are 9.2 ×10¯¹ and 2.762 ×10¯⁴m²/s respectively

Keyswords: aquifers; hydraulic, conductivity; transmissity; storativity