Geoelectric Study of Dam Site of Federal College of Agriculture Akure Southwestern Nigeria

摘要

Geophysical investigation has been undertaken at an existing dam site within the campus of the Federal College of Agriculture, Akure. This is aimed at evaluating the geophysical characteristics of the bedrock along the dam axis and its banks. The survey involved the use of electrical resistivity (VES) depth sounding technique. The Schlumberger electrode configuration was adopted for the field study. Thirty-three soundings were undertaken on nine traverses that were established in North-South directions on the Western (W1-W3) and Eastern (E1-E3) flanks and West-East traverses established on the Southern end of the dam (S1-S3). The three major litho logy units delineated are the topsoil, weathered basement and the presumably fresh/fractured bedrock. The geoelectric section revealed a network of lineaments presumed to be fractures on the S1-S3 and W1-W3 profiles. The geoelectric maps show high resistivity contours straddled with low resistivity lines characterizing the eastern flank thus indicating near-surface bedrock straddled with a basement depression or fracture. The presence of the depression or fracture is considered inimical to the continued retention of water in the reservoir. This is considered responsible for low water level retained in the reservoir in dry season.