Geoelectric investigation of the effect of heavy clay deposits on aquifer potential in Okpara waterside Delta State, Nigeria

摘要

Groundwater is a valuable natural resource that is of immense importance to life. It is naturally stored in the pore spaces within soil compartments and between unconsolidated formations. Its availability and characteristics are greatly determined by the properties of the immediate geologic formations, landfills, toxic wastes and running surface waters etc. Surface geologic presentation of formations in Okpara waterside greatly suggests heavy clay deposits. It is therefore important to investigate the formation strata and its effect of heavy clay deposits on existing aquifer in Okpara waterside. Hence, eight vertical electrical sounds (VES) were made using Schlumberger array to empirically delineate the formation strata and ascertain its effect on existing aquifers. The results show that the formations in Okpara waterside have low resistivities with A, HA and K – curve types and are predominantly compact clay to a depth of 17 m. Viable aquifer is confined and within 27 to 35 m. Its bed consists of medium grain sand, sandy clay and impermeable clay. There is also clear evidence of patched aquifers and water bearing formations at about 10 m and near surface. The aquifer at Okpara Waterside is relatively of good quality due to high level of filtering from compact clay and low levels of domestic and industrial activities and so highly recommended for domestic, commercial and industrial utilities.