Updates on Aquifer Attributes of the Benin Formation within Eastern Niger Delta, Nigeria using Pumping Test and Hydraulic Parameters

Abstract

Evaluation of aquifer hydraulic properties is a prerequisite in the characterization and management of the groundwater resources. It also provides vital information necessary for establishing and categorizing groundwater potentials of the area. Hydrogeological investigations shows that the aquifer in the area is largely unconfined sands with intercalations of gravel and clay. Results of boreholes logs and sieve analysis confirm the dominance of sandy/gravelly horizons in the area. Pumping test results show that the transmissivity ranged between 152.0 m2/day and 2835.0 m2/day with an average value of 1026.0 m2/day while storativity ranged between 9.5x10–6 to 1.5x10–4 with a mean value of 5.8x10–5. The specific capacity varied between 828.0 m3/day and 15314.0 m3/day with a mean value of 6258.0 m3/day. Well discharge ranged between 1624.0 m3/day and 7216.0 m3/day with an average value of 3218.0 m3/day while hydraulic conductivity varied between 3.2 m/day and 478.4 m/day with a mean value of 98.6 m/day. These results obtained were further interpreted by comparing them with the works of Hazen, Gheorge, Krasny, Bouwer, Cooper and Jacob carried out on similar geological formation. These findings clearly established that the aquifer in the area has adequate groundwater potentials to meet the ever-growing water demands for the area. However, in terms of pollution, the aquifer system in the area is highly vulnerable and should be protected as much as possible.