Geo-electrical Resistivity Assessment of the Groundwater Resources Potential of the Waradey Area, Eldas Sub-county, North Eastern Kenya

Abstract

The Waradey Area is located in Eldas subcounty in the greater Wajir County. The area has lacked reliable water structures since independence and was the focus of a concerted geophysical mapping to help avail water to the local populace. To achieve this, Geoelectrical Resistivity Mapping and simulation Models using the GIS techniques were used. This achieved the goals of combining the geophysical models and the hydrogeologic models so generated to build a reliable picture of expectations of the proposed drilling program. The variables simulated using hydrogeologic modeling were aquifer transmissivity, flow-vectors showing direction of movement of water in the subsurface flow systems, salinity, and the aquifer geological material, as well as the water struck levels, which may be used to infer aquifer groundwater levels in the study area.  The geoelectrical models were used to simulate fractures, weathering and moisture content of the underground. The IPI2WIN software was used to model the geophysical VES data so generated. When the two models were combined (ie. both geophysical and hydrogeological), a picture of reliable groundwater potential emerged. On the basis of the foregoing, a well was surveyed and was recommended for drilling, to be discharging up to 10 cubic meters per hour. At worst the models projected a discharge of 2-6 cubic meters per hour. The study has shown the reliability of Vertical Electrical Sounding probes and geospatial models,  as  powerful groundwater exploration tools for the Eldas area, given the limited actual data of hydrogeological drilling in the study locality.