The Collapse of a Precipice: A Crisis in Water Management
The collapse of an ancient and rare palmiet peatland in the Hemel-en-Aarde Valley in September 2023 has exposed serious failures and tensions in the management of South Africa’s water resources. The event, which washed away the popular Onrus estuary and deposited millions of tonnes of mud on private properties, raises critical questions about whether this was a natural disaster or a man-made catastrophe—and if the latter, who should be held accountable?
The Flood That Changed Everything
On 24 September 2023, the Western Cape experienced a Cut-Off Low (COL), a slow-moving low-pressure system that brought 300mm of rain over parts of the province within 48 hours. This extreme weather event led to widespread flooding, landslides, and destruction across the Cape Fold Mountains. In the Hemel-en-Aarde Valley, 135mm of rain caused a dark tide of mud and water to flood the Onrus estuary, turning the ocean black for several days.
Fishermen observed a mass exodus of West Coast Rock Lobster and a die-off of molluscs, including endangered abalone. The riverbed was raised by two metres, and the estuary—once a major tourist attraction—was transformed into a messy dune. The dark clouds of peat rolling in the floodwaters indicated that the peatland had been severely compromised.
The Peatland: A Vital Ecosystem in Decline
What remains of the peatland is now obscured by reeds, with deep ravines fanning out from it, littered with blocks of peat. According to wetlands expert Kate Snaddon, the Onrus River originates at Babilonstoren mountain, 16 kilometres away. Over time, a blockage formed, creating a wetland filled with palmiet (prionium serratum).
“When palmiet dies and decomposes, peat is formed, but it happens very slowly, at a rate of about a millimeter a year,” says Snaddon. Over centuries, more than 30 hectares became covered with peat, reaching depths of nearly eight metres. A healthy peatland functions as a vast carbon sink and a natural filtration system, ensuring a steady flow of clean water downstream.
However, the peatland has faced significant threats. Roads have been cut through it, invasive plants have encroached, and rivers have been impounded, depleting base flows. In 2019, a fire broke out, further damaging the area. The fire burned underground for months, and despite efforts to extinguish it, the peatland began to erode.
The Fire and Its Aftermath
The fire on Camphill Farm in January 2019 spread rapidly, and firefighters struggled to contain it. Winemaker Anthony Hamilton Russell proposed using sandbags and releasing water from De Bos dam, but the municipality rejected the idea, fearing it would affect the community’s water supply. The fire eventually smoldered for nine months, leaving the peatland vulnerable.
Rehabilitation efforts were delayed due to the pandemic, and when the first rains came, they washed away ash, creating head-cuts that undermined the peatland. Over the next two years, the head-cut moved 1,500 metres up the valley, releasing over six-million cubic metres of peat and silt downstream.
The Estuary: A Once-Thriving Ecosystem
Anton Kruger, a kite surfing instructor in Onrus, recalls the estuary’s former beauty. “As kids we used to draw salt prawns and pencil bait from the shallows. You can’t do any of that now,” he says. The estuary has been downgraded to a category F resource, meaning it no longer functions as an estuary.
Kruger joined the Onrus Estuary Forum and discovered dangerously high levels of e-coli in the lagoon. He also found that the amount of water entering the estuary was often barely a trickle. Despite his findings, no one seemed interested in addressing the issue.
The Dam: A Source of Contention
De Bos Dam supplies water to several communities, including Hermanus, Onrus, and Zwelihle. However, the dam has been over-extracted for years, leading to the drying out of the peatland. Russell notes that the peatland used to flood in the 1980s but has not done so in recent decades.
The dam was initially intended to meet the needs of these communities until 2000, but the population has since more than doubled. Despite this, the operating rules from 1973 still apply, and the municipality has exceeded its water allocation limit more than 80% of the time since 2003.
Muddy Waters and Environmental Accountability
In November 2024, a meeting was held by the Breede-Olifants Catchment Management Agency (BOCMA) to address concerns about the ecological damage. BOCMA confirmed that the municipality had over-extracted water, but historical over-extraction would not be held accountable.
Environmental consultant Barry Clark emphasized the challenge of balancing water demands between agriculture, domestic use, and the environment. While the 1998 National Water Act prioritized the environment, implementation has been problematic.
The Road to Recovery
Following the environmental disasters, the Overstrand Municipality launched a project to restore the Onrus Catchment. However, no timelines have been given, and the process must follow strict environmental management protocols.
Kruger has taken legal action, laying criminal charges against officials involved. He argues that the loss of the peatland is irreversible, and the cost of partial restoration is estimated at hundreds of millions of rands.