Climate change impact assessment on water security in South Africa: A case study in a semi-arid river basin

Yali Woyessa,O Chudaev,Y Kharaka,R Harmon,O Shouakar-Stash,R Millot

doi:10.1051/e3sconf/20199806014

Yali Woyessa, O Chudaev + Show 4 more

Open Access

https://doi.org/10.1051/e3sconf/20199806014

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Abstract

The main aim of this paper is to assess the impact of regional climate change scenarios on the availability of water resources in a semi-arid river basin in South Africa using a hydrological model called Soil and Water Assessment Tool (SWAT). In this paper, climate change data was derived from two downscaling approaches, namely statistical downscaling experiment (SDE) and dynamic downscaling (CORDEX). These were derived from the GCM simulations of the Coupled Model Inter-comparison Project Phase-5 (CMIP5) and across two greenhouse gas emission scenarios known as Representative Concentration Pathways (RCP) 4.5 and 8.5. The spatial resolution of the dataset for the SDE method is 25 km × 25 km and 50 km × 50 km for the CORDEX method. Six GCM models were used for SDE set of data and four for the CORDEX set of data. SWAT model was run using these data for a period of up to mid-century (2020 – 2050) for SDE and for a period of up to the end of this century (2020 – 2100) for CORDEX data. The results were then compared with long-term historical data (1975-2005). Comparison of measured data with simulated historical data showed strong correlation (R2 = 0.95 for SDE data and R2 = 0.92 for CORDEX data), which is indicative of the reliability of projected future climate.

Highlights

Water security is understood to be the availability of an acceptable quantity and quality of water for health, livelihoods, ecosystems and production, coupled with an acceptable level of water-related risks to people, the environment and economies [1]
The main aim of this paper is to investigate impact of climate change scenarios on water resources and water security
The downscaled data were derived from the GCM simulations of the Coupled Model Inter-comparison Project Phase-5 (CMIP5) and across two greenhouse gas emission scenarios known as Representative Concentration Pathways (RCP) 4.5 and 8.5

Summary

Introduction

Water security is understood to be the availability of an acceptable quantity and quality of water for health, livelihoods, ecosystems and production, coupled with an acceptable level of water-related risks to people, the environment and economies [1]. The problem of water scarcity is likely to deepen according to some projected climate change scenarios. By 2050, the Southern African region will be generally drier [2]. For South Africa there is a tendency towards a rise in temperature as evidenced in the past five decades [3]. Maximum and minimum temperatures have shown significant increases annually, and in almost all seasons. High temperature extremes have increased significantly in frequency, and low temperatures have decreased significantly in frequency annually and in most seasons across the country [2]

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