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MPhil in Engineering for Sustainable Development

global challenges, engineering solutions

Studying at Cambridge


Upeshika Heenetigala

Building resilience in water supply infrastructure in the southern hemisphere in the face of future uncertainties

Water scarcity is a growing systemic risk. Approximately two-thirds of the global population experience severe scarcity for at least 1 month of the year and cities around the world suffer from extreme hydrological stresses, resulting in catastrophic drought events. This is an alarming indicator that the world is facing an increasingly uncertain future.

This paper provides greater clarity for policymakers in the early stages of the decision-making process by introducing an options evaluation framework using the Analytic Hierarchy Process to assess long-term water infrastructure options. The objective of this framework is to critically appraise these options to provide adaptive, resilient solutions to enhance water security in water stressed cities of the global South.

The method chosen to test this framework is by means of a case study, namely the recent drought in Cape Town, South Africa. The driving forces which contributed to the crisis are assessed and the water supply options being considered by the city are characterised. The results of the sensitivity analysis conducted found that Wastewater Reuse was the preferred option, emphasising that regardless of the water management ethos, reuse should be considered as a baseline supply option for resilient water systems.

The main finding of this research is that in order to cater to the climatic and socio-economic changes that uncertain futures might bring, it is necessary to shift from traditional, linear planning approaches to integrated, systems-based strategies that are resilient and adaptive to change. By adopting the Water Sensitive Urban Design approach, there is immense potential to facilitate equitable transformation in informal urban areas by expanding the existing water systems boundary.