How South African Cities Are Building Water Resilence

With about 464 millimeters of rainfall per year — less than half the global average — South Africa is one of the driest countries in the world. Its semi-arid climate, uneven rainfall distribution and persistent droughts leave the country facing chronic water shortages. At the same time, ecosystem degradation and climate change are causing increasingly frequent and intense flash floods.

Unlike tropical regions in Central and West Africa, where rainfall is relatively reliable, or parts of Eastern Africa with steady seasonal rains, South Africa must manage the growing demand on its limited water resources with extreme care: With high evaporation rates that sometimes exceed average annual rainfall, less than 9% of the country’s rainfall runs into rivers and less than 5% recharges groundwater aquifers. In its cities, rapid urbanization and industrial demand place additional pressure on already fragile water systems.  

South Africa is not alone — cities around the world are grappling with water crises. But some are adapting. Cape Town is restoring its watersheds to help the city withstand major droughts, while eThekwini (the municipality that includes the city of Durban) is investing in improved drainage, nature-based infrastructure and complementary systems, such as early warning flood alerts, to strengthen local responses to extreme rainfall. These efforts show how cities can rethink water management to become more resilient in a changing climate.

Too Little Water: Protecting Supply and Preventing Drought

In 2018, Cape Town nearly ran out of water.

After three years of severe drought, the city was just weeks away from Day Zero, when reservoirs were nearly empty and the government was preparing to shut off the water taps to homes and businesses.

Between February and April that year, residents were gradually limited to 50 liters of water a day — just enough for an average shower — which they collected from designated distribution points. Thanks to strict rationing and other water-saving measures, Cape Town was able to avert the crisis — but it was an extreme example of how droughts can impact cities.  

The Day Zero crisis exposed how fragile Cape Town’s water system was. The city relies heavily on surface water stored in dams, which fill from rainwater running off surrounding catchment areas. But those catchments are under threat, especially from invasive plant species like pine, wattle and eucalyptus.

These trees consume significantly more water than native vegetation, reducing the amount that reaches reservoirs and, ultimately, shrinking the city’s water supply. In fact, invasive species use about 4% of the country’s available water every year — enough to meet the needs of at least 15 million people.  

To build a drought-resilient city, Cape Town has turned to nature-based solutions, including removing invasive plants and restoring degraded catchment areas. These efforts are not only eco-friendly — they’re also much cheaper to implement than costly engineered alternatives such as groundwater exploration, desalination (removing salt from seawater) and recycling wastewater.

Implementing Nature-Based Solutions

In the wake of the Day Zero crisis, the Greater Cape Town Water Fund was launched — a public-private initiative led by the city, The Nature Conservancy (TNC) and other partners. It’s designed to protect Cape Town’s key catchment areas through a payment-for-ecosystem-services model. Through this initiative, the municipality and local businesses pool funds to pay upstream communities to restore the land that supplies the city with water.

These upstream stewards include small-scale farmers, private landowners, small community businesses and local youth and women. They’re trained to remove invasive plants using a mix of herbicides, ringbarking (stripping a deep band of bark from the tree trunk to cut off nutrients to the canopy) and manual clearing. Over the years, TNC has also trained a specialized team of high-altitude rope technicians to tackle invasive species on steep mountain slopes that are otherwise inaccessible.

So far, the Water Fund has cleared nearly 63,000 hectares of invasive alien plants. Where they once crowded out the region’s native flora, the iconic fynbos (a unique shrubland found only in South Africa), which includes native species like the King Protea and Sugarbush, is now taking root. This ecological shift is freeing more than 17 billion liters of water every year, helping the city move closer to its long-term goal of recovering 100 billion liters annually by 2050. 

As well as removing invasive species, efforts are underway to restore native vegetation and rebalance ecosystems. In the Breede and Berg riverbanks, a partnership of environmental NGOs, government departments and water management bodies is working with local communities to slow the spread of invasive species and plant tens of thousands of native trees across the catchment.

These efforts are a win for both water security and biodiversity, as invasive species are replaced with eco-friendly indigenous trees and shrubs such as wild olives and fynbos. It’s also brought employment opportunities — more than 300 jobs so far — as well as new recreational activities to the region. These nature-based interventions are not just cost-effective; they’re strategic. If invasive species continue spreading across Cape Town’s catchments, the city’s water losses could double by 2045.  

A study by the Development Bank of Southern Africa on the country’s water investment gaps towards 2020 found that, despite high upfront costs, removal efforts reduce the need for expensive water infrastructure projects later on. When comparing total future costs, actively clearing invasive plant species reduces investment expenditures by 9% by 2050, while inaction increases costs by about 13% — a total potential cost savings of 22% for the country. 

Too Much Water: Preventing Flooding and Riverine Risks

In 2022, the eThekwini Municipality — home to Durban, a coastal city located in KwaZulu-Natal — faced the opposite of Cape Town’s drought crisis.

It suffered one of the deadliest and most damaging floods in South Africa’s history. More than a third of the region’s expected annual rainfall fell in just 24 hours, causing extensive damage to homes, infrastructure and ecosystems, costing the city more than $1.5 billion. More than 400 lives were lost, and tens of thousands were displaced.  

eThekwini faces some of South Africa’s most complex river and flood-related challenges. Home to more than 7,400 kilometers of rivers and streams, and facing an increasingly unpredictable climate, the region is particularly vulnerable to both flash floods and prolonged inundation. Rapid, informal urban expansion adds further pressure. Settlements often spread along riverbanks and in low-lying floodplains, where housing, roads and drainage systems are ill-equipped to withstand the heavy seasonal rains that are intensifying with climate change.  

The city has taken bold steps to reform riverine management with the launch of its pioneering Transformative Riverine Management Programme (TRMP) in 2020 — one of the most ambitious efforts in the country to align communities, government and businesses around the value of restoring and protecting urban rivers. 

Rather than treating river restoration as a narrow or localized issue, the TRMP takes a holistic approach, recognizing the many pressures that contribute to flooding in riverine areas, including informal settlements in floodplains, stormwater runoff, solid waste and debris in the city’s rivers, and invasive plant species in and around the city’s water bodies. To address these issues, the municipality is working with communities along river corridors to help clear invasive plants and waste, promote river stewardship and maintain stormwater and sewer infrastructure. All of these actions help strengthen the city’s natural and built infrastructure to better absorb and manage stormwater during heavy rains.

The program has also supported creating retention ponds (a basin that holds stormwater runoff and slowly releases it), weirs and wetlands to slow water flow and reinforce riverbanks. In addition, community-driven early warning systems have been introduced to alert residents ahead of extreme flood events.

These investments in flood resilience make financial sense in the long run. The TRMP helped eThekwini build a solid business case for riverine resilience, showing that every dollar spent could generate between 1.8 and 3.4 times its value in broader social, environmental and economic benefits.

In 2022 alone, the city spent upwards of $1.5 billion in flood recovery, including repairs to roads, sewage systems and power lines — a huge cost for the city. Under business-as-usual scenarios, eThekwini faces annual losses of $9 million in infrastructure repair costs. But with a city-wide TRMP, the city will be able to save upward of $100 million in future infrastructure maintenance and recovery costs, particularly for flood-resilience assets like its culverts (a pipe or tunnel that allows water to flow under roads, railways or pathways).

These interventions go beyond ecological and social gains. They also reduce risk for businesses and insurers. Major floods can lead to soaring insurance premiums for companies with high-value assets, as well as cause significant financial losses for insurers. In this context, the TRMP has helped elevate river management as a shared priority across public and private sectors. It also brings wider benefits, from job creation and urban greening to stronger institutional coordination — showing how a systems-based, participatory approach can generate meaningful progress in riverine resilience. 

Toward a Shared Urban Water Future

The experiences of Cape Town and eThekwini show how cities around the world can strengthen urban water resilience through community-based approaches and the protection of natural ecosystems. While water challenges can be severe, integrating nature-based solutions with forward-looking planning can help communities better manage water risks in a changing climate. 

For Johannesburg, and other cities across the world, climate change, rapid urban growth and aging infrastructure mean the economic, environmental and social costs of inaction will only keep growing. But restoring rivers and catchment areas offers a rare opportunity to tackle multiple challenges at once: floods and droughts, supporting biodiversity, improving equity, making public spending more efficient and helping secure long-term water supply. It’s a lesson worth learning from the cities already leading the way.