Assessment of spatial and temporal distribution of surface water balance in data-scarce African transboundary river basin
Domaine:
environment and energyType de record:
Assessment of the spatial and temporal distribution of surface water balance (SWB) is crucial for the sustainable planning and utilization of surface water resources, especially in large-scale transboundary river basins. The detailed assessment, however, requires several hydrometeorological data and physical parameters related to the catchment. Thus, developing a model to analyse the SWB of the large-scale river basin with the lack of observed data and complex topography is highly challenging. Therefore, this paper aimed to estimate the spatial variability of average monthly, seasonal, and annual SWB such as actual evapotranspiration (AET), surface runoff (SRO), and interception (I) using the WetSpass-M physical-based hydrological model. The standardized potential evaporation index (SPEI) package of R-studio was used to estimate PET and spatially interpolated for the catchment using ArcGIS system. Further, PET and AET used for estimation of mean monthly spatial variation of crop water deficit (WD). To demonstrate the potential of modelling approaches used in this paper, the large-scale East African River basin, such as the Omo River basin in Ethiopia, which has limited data, was chosen. The sensitivity of global and local parameters of the WetSpass-M model for SWB was analysed. It was found that AET and I are insensitive to average rainfall intensity, while SRO is highly sensitive. The spatial and temporal variation of SWB under different combinations of land-use land cover (LULC) and soil type indicates that SWB such as SRO, AET, and I are influenced more by LULC than by soil type.