Abstract
Growing water demand poses a challenge for supply. Poor understanding of alternative sources can hamper plans for addressing water scarcity and supply resilience. The potential of three alternative supply systems in Lilongwe, Malawi and Sharm El-Sheikh, Egypt are compared using a fast, data-light assessment approach. Lilongwe water supply is based on unsustainable use of source water, while Sharm depends primarily on desalination. Both locations experience shortages due to poor system performance and service inequity. Alternative supply systems are shown to potentially contribute to supply augmentation/diversification, improving service and system resilience. There are considerable seasonal variations to consider, especially regarding storage of water. Social preferences could limit the uptake/demand for alternative water. One important conclusion is the value in addressing public perceptions of alternative systems, and assessing water end use in order to site systems appropriately. Other issues surround financing, encouraging uptake and addressing institutional/governance aspects surrounding equitable distribution. A further consideration is whether demand reductions might yield shorter-term improvements in performance without the need to institute potentially expensive alternative water strategies. Reducing non-revenue water is a priority. Such measures should be undertaken with alternative supply enhancement to reduce inequity of supply, improve system performance and increase resilience to future changes.