Babatunde ABIODUN, University of Cape Town, South Africa
Abayomi A. ABATAN, University of Cape Town, South Africa
Brilliant M. PETJA, University of Cape Town, South Africa
Mariam NGUVAVA, University of Cape Town, South Africa
Myra NAIK, University of Cape Town, South Africa
Tlakale MOGEBISA1, University of Cape Town, South Africa
Nokwethaba MAKHANYA, University of Cape Town, South Africa
Rosita YOCGO, University of Cape Town, South Africa
The Vaal River basin is the heartbeat of many socio-economic activities in South Africa, but the impacts of climate change and variability, which manifest as hydrological droughts, remain a big challenge to water availability in the basin. While studies have discussed the influence of land use/land cover (LULC) changes in the river basin, there is a dearth of information on how LULC changes can be used to mitigate climate change impacts in the river basin. The present study examines the extent to which LULC changes can be applied to reduce climate change impacts on the Vaal River basin (South Africa) with a focus on hydrological droughts. The study used various drought indices to characterize droughts, analyzed multi-climate datasets, and performed a series of hydrological simulations over the basin using a calibrated, process-based hydrologic model (called SWAT+). The climate change impacts on hydroclimate variables and drought frequency are projected at four global warming levels (1.5oC, 2.0oC. 2.5, and 3.0oC) and the extent to which four LULC change scenarios (i.e., expansion of grassland, cropland, cropland/grassland mosaic, and barren land) can influence the projections are quantified. The results show that the SWAT+ model reproduces the temporal and spatial distribution of streamflow in the Vaal River basin. The model simulations project a uniform increase in temperature across the basin with a decrease in precipitation, soil water, percolation, surface runoff, and streamflow over most parts of the basin. The simulations reveal that the expansion of grassland can reduce the climate change impacts on soil water, percolation, and the associated drought frequency, but the magnitude of the reduction is small compared to the climate change impacts. The study has application in developing mitigation and adaptation strategies to minimize climate change impacts on water yield in the Vaal River basin.
Mots clés : Climate change|Vaal Basin|Land use|Drought|Drought managment
A104514BA