Sustaining Urban Water Supply under Climate Change: Lessons from selected rapidly growing cities in Southern Africa and China

Water is the basis for life, and meeting water supply demand is a global challenge, particularly in developing countries. In 2020, it was estimated that two billion people lived in water-stressed regions with no access to a safely managed drinking water service on premises, available when needed and free of contamination. This condition is expected to worsen in some regions due to climate change and rapid population growth. The United Nations World Water Development Report 2020 estimates that by 2050, some 685 million people will live in over 570 cities; and will likely face a decline in freshwater availability of at least ten percent because of climate change. Water use worldwide has been growing at more than twice the rate of the global population in the last century. Combined with a more erratic and uncertain supply, this will aggravate the situation of water-stressed regions and generate water stress in areas with currently abundant water resources.

The 2030 Agenda for Sustainable Development, adopted in September 2015 by world leaders at the United Nations General Assembly, includes Sustainable Development Goal (SDG) 6 to “Ensure availability and sustainable management of water and sanitation for all”. Specifically, the Goal commits to the following targets:

  • Target 6.1: “Achieve universal and equitable access to safe and affordable drinking water for all”.
  • Target 6.3: “Improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally”.
  • Target 6.4: “Substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity and substantially reduce the number of people suffering from water scarcity”.
  • Target 6.5: “Implement integrated water resources management at all levels, including through transboundary cooperation as appropriate”.
  • Target 6.6: “Protect and restore water-related ecosystems, including mountains, forests, wetlands, rivers, aquifers, and lakes”.
  • Target 6.a: “Expand international cooperation and capacity-building support to developing countries in water- and sanitation-related activities and programmes, including water harvesting, desalination, water efficiency, wastewater treatment, recycling and reuse technologies”.

Agenda 2030 includes Goal 11 to “Make cities and human settlements inclusive, safe, resilient and sustainable”. This Goal commits countries to “ensure access for all to adequate, safe and affordable housing and basic services and upgrade slums” (target 11.1). Additionally, Goal 13 requires governments to “Take urgent action to combat climate change and its impacts”, specifically to “integrate climate change measures into national policies, strategies and planning” (target 13.2) and to “improve education, awareness-raising and human and institutional capacity on climate change mitigation, adaptation, impact reduction and early warning” (target 13.3).

In the New Urban Agenda, adopted in 2016 at the third United Nations Conference on Housing and Sustainable Urban Development (Habitat III) in Quito, Ecuador, Member States committed to long-term urban and territorial planning processes and spatial development practices that incorporate integrated water resources planning and management, considering the urban-rural continuum on the local and territorial scales and including the participation of relevant stakeholders and communities. Agenda 2030 and the New Urban Agenda reaffirm the promise of world leaders to seek solutions to sustainable water supply and management. Increasing water-use efficiency while advocating for sustainable water supply practices, recycling, and reuse are urgent global priorities.

Alternative water sources such as wastewater, stormwater runoff, and desalination plants, and instituting measures like water harvesting and rationing, can help relieve water stress. Safe wastewater treatment, reuse, and recycling is, so far, an untapped and significant resource. Developing countries can learn from China’s experience in wastewater treatment technology, including the removal of hazardous chemicals for safe use. The cities of Windhoek (Namibia) and Shanghai (China) case studies suggest that future innovative solutions will require a mix of the following: cost-effective water treatment technologies, wastewater reuse, sea and groundwater desalination, water harvesting (rainwater, stormwater, aquifer recharge), and transboundary water sources. The cities of Bulawayo (Zimbabwe), Gaborone (Botswana), and Windhoek also propose tapping into transboundary river sources. Promoting water-use efficiency in Shanghai through technologies used in industry and household appliances plays a central role in meeting water supply demand. Furthermore, strict urban planning standards coordinated with long-term engineering and water supply plans and strategies ensure adequate water supplies to all new developments in China.

This publication aims to provide a valuable reference source for all those involved in water supply and management in urban areas of developing countries. It aspires to encourage regions, countries, and cities to prioritize investment in and the financing of sustainable long-term water supply management actions within the context of climate change in the rapidly urbanizing world.


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