Hydrogeophysical Survey Design and Management for Rural Water Supply in Kaduna State

This study examines hydrogeophysical survey design and programme management for rural water supply borehole siting in Kaduna State, North West Nigeria. Rural water supply in Kaduna State is critically dependent on borehole groundwater, but conventional borehole siting without geophysical investigation yields high failure rates, wasting limited public investment. Systematic hydrogeophysical survey design and management can significantly reduce borehole failure rates and improve the cost-effectiveness of rural water supply programmes. This study develops and implements a hydrogeophysical survey management framework for a 40-borehole programme in five Kaduna State local government areas, comparing outcomes against a concurrent conventionally sited programme of equivalent scale. The framework integrates satellite lineament analysis for pre-survey target identification, VES survey at defined station densities, quality control procedures for field data acquisition, and decision support criteria for translating geophysical results into borehole recommendations. Programme management aspects including scheduling, quality assurance, reporting, and post-drilling validation are documented. Findings reveal that the managed hydrogeophysical approach achieves a borehole success rate of 87.5 percent compared to 62 percent for the conventional programme. Average borehole yield in geophysically sited boreholes is 2.8 litres per second versus 1.6 litres per second in conventional boreholes. Total programme cost per successful borehole is reduced by 28 percent in the geophysical programme despite the additional geophysical survey cost, due to significantly lower dry hole rates. The study recommends mandatory pre-siting hydrogeophysical survey as standard practice for all Kaduna State rural water supply programmes.

Keywords: hydrogeophysical survey, rural water supply, borehole siting, Kaduna State, survey management.