GEOPHYSICAL SURVEY ON GROUNDWATER PREDRILL FOR THE CONSTRUCTION OF WATER BOREHOLE IN OBIO/AKPOR LOCAL GOVERNMENT AREA, RIVERS STATE, NIGERIA
Keywords:Geophysical Survey, Groundwater, Predrill, Potential, Borehole, Obio/Akpor
Predrilling groundwater geophysical survey for the construction of water borehole in Obio/Akpor Local Government Area, Rivers State, Nigeria, was conducted using a detailed Vertical Electrical Sounding (VES) with the Schlumberger configuration, Spontaneous Potential (SP) and Resistivity (Short and Long Lateral) geophysical methods to ascertain the groundwater potential in the study area. The sounding curves show three layers to four layers earth models. It could be suggested that the low resistivity and significantly thick weathered rock/clay constitute the aquifer in the study area. The north central, northeastern, eastern, southeastern, south central and southwestern part from the maps of weathered layer thickness and groundwater potential, signify that groundwater potential is moderate in these areas. The western part of the study area showed a very thin weathered layer which indicates low groundwater potential area, while the northeastern, central, and southeastern axes of the study area are of high groundwater potential. Results from the study has revealed that 9 VES stations are most viable locations for the development of groundwater in the study area. However, about 11 VES stations could be considered as fair for borehole development while the remaining 10 VES stations could be considered to exhibit low prospects. The study has established the fact that some parts of Obio/Akpor LGA contain reasonable amount of groundwater which if well tapped will go far to reducing the water problem in the Local Government Area. Further studies using integrated geophysical investigation for subsurface characterization which will aid community planning in terms of water works construction should be carried out and areas of high ground water potential as indicated from the findings of this work should be noted and earmark for borehole establishment.