Abstract:
This study assessed drought risk in Kaduna River Basin (KRB) and its implications for
agricultural planning. In achieving this, monthly data on rainfall, temperature, streamflow and
crop yields (maize, millet and soybean) were sourced from relevant government agencies such as
Nigerian Meteorological Agency (NIMET), Nigeria Hydrological Services Agency (NIHSA),
Kaduna State Water Board, Shiroro Hydro-Electric Power Station Niger State Agricultural
Development Project (NADP) and Kaduna State Bureau of Statistics (KDBS) for ten
hydrometeorological stations (1990-2018). In addition, rainfall data were obtained from the
Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) website while
temperature and soil moisture data were retrieved from the ERA5 Copernicus data archive (in
NetcDF) and then processed in Ferret PMEL (Linux-based) software to augment the
hydrometeorological data. Landsat imageries 4, 5, 7 and 8 of 30m resolutions were also used to
generate Vegetation Condition Index (VCI), Modified Normalized Difference Water Index
(MNDWI) and Landuse/Landcover (LULC). DrinC (Drought Indices Calculator) software was
used to calculate Potential Evapotranspiration (PET), Reconnaissance Drought Index (RDI),
Standardized Precipitation Index (SPI), Agricultural Standardized Precipitation Index (ASPI) and
Streamflow Drought Index (SDI) while GIS technique was used to examine the spatial
dimension of drought. Pearson Correlation Coefficient Analysis was used to examine the
relationship among the three drought indices and crop yields. Water Balance (WB) model was
further used to estimate other WB components such as actual evapotranspiration (ETa), Water
surplus (S) and Runoff (R). KRB was divided into two sub-basins (lower stream and upstream).
Agricultural and hydrological drought vulnerability maps were equally produced in this study.
The result from WB analysis showed the peak of R generally occurs during the wet season (April
through October) mostly at the upstream. The study further revealed that the runoff efficiencies
imply that <44% of annual P results in R at the upstream while <27% of annual P results in R at
the lower stream. Also, from the result, it was found that Soil moisture (SM) utilization occurs
mostly towards the end of the year through to the early months (November through March)
across the basin while the majority of S is generated during wet season months, particularly from
April through October when ~95% of S occurs on average with the peak S in August. The study
revealed the base year of 1998/1999 as common year of drought onset for meteorological,
