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

Abstract

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: 21-26