Towards Sustainable Urban Water Management in the Global South

Abstract

Many cities in Sub-Saharan Africa struggle to access reliable and adequate quantities of potable water for diverse water requirements. Under pressure of climatic change, urbanization and economic development, freshwater resources are becoming scarcer. These pressures combined with outdated infrastructure, pose a giant challenge to the Greater Maputo Region to meet their water demand in 2050. This report aims at identifying and analyzing pathways, using stakeholder preferences, that support SUWM and bear the potential to close the supply-demand gap in 2050.

This report utilizes population and demand forecasting to determine the gap between future supply and demand. Hereafter, alternative technical, social, and environmental methods to augment the Greater Maputo Region’s water supply are identified through a literature study. Furthermore, two distinct methods are used to develop scenario’s that augment the supply demand gap. The first being a technical analysis using multi-criteria decision analysis and the second a serious game that is to be played with stakeholders. At last, these scenarios are used to develop a framework that is technically feasible and approved by stakeholder opinions in the serious game.

It was found that the population of the Greater Maputo Region will grow from 2,8 million in 2017 to 6,9 people in 2050. Furthermore, under the pressure of economic development, population growth and urbanization, water demand increased from 9 million m3/day in 2017 to 22 million m3/day in 2050. This increase in demand, in the case of a business-as-usual scenario, amounts to a deficit of 1,2 million m3/day in 2050. The sector that consumes most water is agriculture, followed by industries and households. Furthermore, under climate change precipitation decreases over time whereas temperatures increase. Especially during the dry period, more evaporation and less rainwater is expected, highlighting the need for alternative water supply methods to ensure a steady availability of water.

Alternative methods that support SUWM such as dams, stormwater harvesting, rainwater harvesting, wastewater reuse and desalination were found to be most suitable approaches to augment the Greater Maputo Region’s water supply. However, it was also found that these approaches are not very efficient without the right urban context and socio-political and economic measures. Economic and social-political measures should incentivize water savings and fair distribution.

Two distinct methods were used to create scenarios to close the Greater Maputo Region’s supply demand gap. The first, multi-criteria decision analysis showed that that in the case of a high weight attributed to the cost of approaches, rainwater harvesting, stormwater harvesting, and dams are the most suitable options given the selected criteria and their respective rank. Whereas in the case of a low weight of the cost, wastewater reuse, stormwater harvesting, and rainwater harvesting are the most suitable. The second, a serious game that mimics the WASH situation in the Greater Maputo Region which showed that players focus on sustainable, circular, solutions, but that they are hard to implement because of financial limitations.

Ultimately, this report indicates that both decision analysis and serious gaming provide valuable insights for enhancing water supply in an urban context. In this report, both methods indicate that there is a preference for circular (sustainable) approaches. Such an ideal, circular, and sustainable, water system in the Greater Maputo Region, was found to be supported by decentralization of the water sector. In this case, decentralization of the water sector to a neighbourhood scale shapes niches for sustainable water supply approaches and within these niches, the local context of the neighbourhood determines the type of water supply infrastructure that is most suitable. Furthermore, the technical approaches are to be supported by socio-political and economic measures. Altogether, a combination of SUWM supporting approaches supported by political and socio-economic measures can close the supply-demand gap in 2050.