Hydroclimatology of the Kaduna River Basin

Abstract

This study examined the hydroclimatology of the Kaduna River Basin (KRB) in northern Nigeria. In achieving this, monthly data on temperature (T) and rainfall (P) were sourced from ten hydrometeorological stations across the basin from 1990 to 2018. DrinC (Drought Indices Calculator) software was deployed to calculate Potential Evapotranspiration (PET) adopting Thorn-thwaite approach. Water Balance (WB) model was used further to estimate other WB components i.e. soil moisture (SM), actual evapotranspiration (ETa), Water surplus (S) and Runoff (R). WB components are used to ex-amine the temporal and spatial variability of the KRB for hydrological years (1990-2018). KRB was divided into two sub-basins (Lower and Upper KRB). The WB analyses indicated the peak of R generally occurs during the wet season (i.e. April through October) most especially at the Upper KRB. The study further reveals that the runoff efficiencies imply that <44% of annual P results in R at the upper KRB while <27% of annual P results in R at the lower KRB. The study shows that SM utilization occurs mostly towards the end of the year and at the early months (i.e. November through March) across the basin while the majority of S is generated during wet season months, particu-larly from April through October when ~95% of S occurs on average with the peak S in August. The results of this study provide a baseline understanding of the hydroclimatology of the KRB which can be used as a starting point for further analyses, especially for water resources management.