Aquifer Vulnerability Investigation Using Geoelectric Method in Parts of Sapele Local Government Area of Delta State, Nigeria

The electrical resistivity survey has been used in the determination of the overburden protective capacity in Amukpe area of Delta State, Nigeria. Nineteen Schlumberger vertical electrical soundings (VES) were carried out with maximum electrode separation of 1000m. The data were presented as VES curves interpreted quantitatively by computer iteration using the Resist Software to obtain the first order geoelectric parameters. Three geoelectric layers namely the topsoil, laterite/clayey sand and sand (medium to coarse grained) were delineated from the survey. The topsoil has resistivity values ranging from 43 to 1067Ăm and thickness varyingfrom 0.8 to 1.6 m. The second geoelectric layer is composed of clayey sand and laterite with resistivity values ranging from 77 to 644 Ăm and thickness varying from 3.8 to 6.7 m. While the third geoelectric layer represents the aquiferous unit with resistivity values ranging from 200 to 1067 Ăm diagnostic of sand (fine to coarse grained). The interpreted geoelectric data correlated with lithologic logs of a borehole drilled in the study area. The overburden protective capacity in an area was evaluated by utilizing the total longitudinal unit conductance values. The generated longitudinal conductance map showed poor protective capacity (<0.1mhos) in all parts of the study area. The low value of the protective capacity makes the aquifer in the study area vulnerable to contamination especially hydrocarbon in the event of pollution.Keywords: Protective capacity, Amukpe, Geoelectric, Pollution

Geoelectric study of the clay deposit in Agbede, Estako west LGS, Edo state

No Abstract.Global Journal of Pure and Applied Sciences Vol. 13 (2) 2007: pp. 215-22

Geoelectric investigation of the aquifer characteristics and groundwater potential in Kwale, Delta State, Nigeria

Subsurface geo-electrical survey using the electrical resistivity (VES) method and drillers logs were carried out in Kwale, Ndokwa West Local Government Area of Delta State in order to investigate the aquifer characteristics and ground water potential of the subsurface formations. Nineteen vertical electrical soundings were carried out within the town and its environment using the Schlumberger array configuration. The data was interpreted using the conventional curve matching and computer iteration method. The results reveal a five layer HKH, KQH and AKH type curves. The true resistivity of the top soil varies from 55-236Ωm while the thickness varies from 0.7-1.0m. The second layer has resistivity ranging from 37-627 and thickness ranging from 1.3-3.6m. This layer is composed of clay to sand. The third layer, which constitutes an aquifer, has resisitivity varying from 2.7 to 411Ωm while the thickness varies from 4-17m. It is composed of fine-grained sand. The fourth geoelectric layer has resistivity values ranging from 114 to 168Ωm while the thickness varies form 15 to 35m. This layer is composed of fine to medium-grained sand. The soft layer has resistivity ranging from 326-2308Ωm. This layer is composed of medium coarse-grained soil and it constitutes an aquifer of very good quality groundwater. The average depth of this aquifer is between 30-40m. These results were correlated with lithological logs from boreholes drilled in the study areas and were found to be consistent. Journal of Applied Sciences and Environmental Management Vol. 9(1) 2005: 157-16

Geophysical investigation of the source of river Ethiope in Ukwuani LGA of Delta State, Nigeria

Investigations were carried out at the Source of river Ethiope in Ukwuani LGA of Delta State using schlumberger array of Vertical Electrical Sounding (VES) and horizontal profile of Seismic Refraction methods to delineate the formations within and around the river. A total of twelve VES locations were sounded while nine randomly selected Seismic refraction stations were shot. Each VES study was made with a current spread of 928 metres while the Seismic refraction lines had a geophone spread of 39 metres each along the profile, with a 3 - metre geophone offset from the sleigh hammer source. The results show that sites on the lee side have two velocity layers and AHK or HA curve types with viable aquifer at 40 m-45 m. In contrast, sites north of the source show evidence of three velocity layers with AQ curve type and remarkable with dry or failed wells at depths of 90m. At the source, there is evidence of rapid and continuous groundwater flow close to surface with QA or HK curve types. Keywords: geophysical investication, river Ethiope, Schlumberger array, vertical electrical sounding Nigerian Journal of Physics Vol. 17, 2005: 21-2