The role of open-access hydrological information systems in water security risk assessment in Cape Town

Abstract

The City of Cape Town (CCT) faces the prospect of an uncertain water future due to climate change, increasing demands, and delayed interventions. Augmentation and diversification of water resources have been mostly reactive, which resulted in the drought experienced since 2015 and culminated in the threat of “Day Zero” in 2018. The impact of the drought was experienced across domestic, business and agricultural domains, with immeasurable direct short-, medium- and long-term financial implications. With water being a mobile common pool resource, achieving water security (WS) requires a flexible and dynamic approach. The aim of this research was to assess the water security status quo versus the impact of the proposed water augmentation projects of the New Water Programme, and to determine the relative risk impact of the augmentation projects to water security by identifying and ranking the related risk factors. The research followed a quantitative systematic empirical investigation within a positivist paradigm to produce a water security risk assessment using open-access hydrological information systems (HISs). Archival data collection was adopted as instrument to review secondary quantitative data resources available in the public domain, with no human participation and no significant ethical implications. The findings present a dynamic water security risk assessment for the CCT that confirms water security during normal rainfall years through augmentation projects reducing Cape Town’s dependence on supply from the Western Cape Water Supply System (WCWSS). The risk analysis found population growth as the biggest threat to WS and water re-use as the most positive contributor to future WS. The research results are aligned with the objectives of the Western Cape Water Supply System Reconciliation Strategy, which are to reconcile future water requirements with supply for a 25‐year planning horizon, and to provide a framework for decision‐making with regard to both securing supply and managing demand.