Groundwater Potential In Kidiani Area, Kwale District, Kenya

Abstract

This work describes the results of a hydrogeological project carried out in Kidiani Area of Kwale District, some 60 kilometres south-west of Mombasa. In the mentioned area, vertical electrical sounding measurements (VES) were conducted. Here, potables water zone occur in both Magarini Sands and Mazeras Sandstones aquifers. Iterative, non-automatic inversion of VES data, coupled with well data, resolved with some confidence the conductive/non- conductive water interfaces and revealed some correspondences between the lithostratigraphical units and the resistivity values. The maps of resistivity and transverse resistance values agree reasonably with the general hydrogeological conditions in the area. Within the Mazeras Sandstones the results suggest that groundwater is strongly connected with the presence of structural features in the subsurface where seasonal recharge is likely. Correlations have been established between the conductive zone resistivity and the water salinity and to a lesser extent between the transverse resistance and the project area for groundwater prospecting. Jacob straight line method of analysis of recovery test data resolved with sufficient confidence borehole/aquifer hydraulics which included Transmissivity and Specific Capacity. Determination of some aquifer limitations and to a lesser extent, relative borehole efficiency were also made. The approach established in this project could be used to assist in exploration and evaluation of groundwater resources in new target areas in the Coast Province, where lithostratigraphical and hydrogeological informations are very limited.