By Zimkita Mavumengwana
When South Africans talk about water security, the conversation often turns to taps running dry, ageing pipes, or the spectre of another Day Zero. These are real and urgent concerns. But they are only part of the story. The National Biodiversity Assessment (NBA) 2025 reminds us that the infrastructure delivering water to our homes begins long before treatment plants and reservoirs, it begins in our rivers, wetlands and catchments. As we mark Wetlands Day on 2 February, it is a timely reminder of the vital role these ecosystems play in sustaining life and water security.
What the National Biodiversity Assessment reveals about freshwater ecosystems
The National Biodiversity Assessment (NBA), released in late 2025, paints a sobering picture of the state of South Africa’s freshwater ecosystems. Around 65% of river length and 86% of wetland ecosystem extent are threatened, and only about a quarter of the country’s river length remains in a natural or near-natural condition. Pollution, unsustainable water abstraction, habitat modification or degradation, and invasive alien species are steadily eroding the ability of these systems to function. This is not only an environmental concern; it is a growing risk to the water supply on which households, agriculture and industry depend.
Pic: Jeremy Shelton
What often gets overlooked is that rivers and wetlands are not simply “nice to have” environmental features, they are ecological infrastructure. Healthy freshwater ecosystems filter pollutants, regulate flows during floods and droughts, recharge groundwater and reduce the cost of water treatment. The NBA 2025 highlights the outsized importance of Strategic Water Source Areas, which make up only 10% of the land area of South Africa, Lesotho and Eswatini yet supply roughly half of the water to these countries. When these areas are degraded, no amount of downstream engineering can fully compensate.
The NBA 2025 makes a clear case: investing in ecological infrastructure is as crucial to water security as investing in pipes, dams and treatment works. This is not an argument against built infrastructure, but for a more balanced approach – one that recognises that grey infrastructure and healthy ecosystems can work together. Restoring wetlands, protecting rivers from pollution, managing invasive species and securing natural flow regimes are practical, cost-effective ecological infrastructure interventions that strengthen water resilience over the long term.
Signs of progress and reasons for optimism
Encouragingly, this is not a story without solutions. Across the country, partnerships between government, scientists, landowners and communities are demonstrating that restoring ecological infrastructure can improve water quality, reduce flood risks and create jobs. These examples reinforce an important message from the NBA: safeguarding nature is not at odds with development, it underpins it.
Pic: Jeremy Shelton
This message is powerfully captured in a short film titled ‘Flow for Life’ accompanying the NBA findings, which traces the journey of water through our landscapes and highlights the quiet work that rivers and wetlands do every day. Rather than focusing on crisis alone, the film invites us to see freshwater ecosystems as allies – living systems that, if cared for, can help secure a reliable water future for South Africa.
As the country grapples with water challenges intensified by climate change and growing demand, the real question is not whether we can afford to invest in ecological infrastructure — it is whether we can afford not to. By protecting and restoring the natural systems that supply and clean our water, we invest in resilience, equity and long-term security for both people and nature.