Delineation of groundwater potential zones using electrical resistivity technique in Obudu basement terrain of Cross River State, Southeastern Nigeria

Abstract

Groundwater exploration in basement terrain can be somewhat challenging. Aquifer parameters like hydraulic conductivity and transmissivity can help in predicting groundwater potential zones in basement terrains. The vertical electrical sounding investigation that involved the Schlumberger configuration was employed to map the subsurface layers within the crystalline basement of the Obudu Complex, southeastern Nigeria. Secondary electrical resistivity data (Dar Zarrouk parameters) and a few pumping test-derived hydraulic parameters (i.e., transmissivity and hydraulic conductivity) were employed to develop empirical models. These models were used to predict hydraulic parameters at locations where only geoelectrical parameters (i.e., aquifer layer thickness and electrical resistivity) exist. Results showed that the northeastern part of the study area and areas located within zones of major faults displayed relatively higher values of hydraulic conductivity and transmissivity. The study area was classified into good, moderate, and poor groundwater potential aquifer zones. This integrated approach can be adopted in other areas with similar geology, where pumping test information is scarce or limited, as an alternative means of predicting aquifer properties and delineating groundwater potential zones for sustainable development and management of groundwater resources.

Delineation of Groundwater Potential and the Susceptibility to Surface Contaminants

“…The parameters and in equations ( 8) and ( 9), which according to [47,48], can be used to evaluate the area aquifer potential. That is, the high and values usually indicate relatively high thick succession layers and it should be the focus in terms of groundwater potential [49,50,51,52,53,54]. On the other hand, [5,55], noted that the earth most times acts as a natural lter to the in ltrating uid, especially when the earth's subsurface is underlain with an indurated laterite and impermeable clayey, which in turn de nes its ability to resist uid and the degree of its protective capacity [1].…”