Neglect turns Cape Town’s Diep River Canal into a stinking sewage trap

Years of neglect have turned Cape Town’s Diep River Canal into a sewage-filled nightmare for residents, impacting on both wildlife and the quality of life in the area.

Despite repeated complaints and meetings with city officials, residents said that a vital silt trap remains uncleaned, leading to unbearable smells and ecological devastation in this southern suburbs community.

Residents are calling for urgent intervention and the re-establishment of proper maintenance protocols to restore the canal to its original state.

Joan Stokes has lived next to the Diep River Canal for 35 years. In the early days, she recalls a well-maintained system where the City of Cape Town regularly cleared the silt trap next to her house. Today, however, the canal is a site of chronic neglect, filled with layers of silt, raw sewage and other filth that has created an “absolutely horrific” situation for residents.

The canal was originally converted from a river with a specific purpose: to manage silt runoff. Stokes said in an interview with Daily Maverick that upstream, toward Constantia, the waterway is still a “proper river” with natural banks.

To prevent silt from blocking the entire canal, a silt trap was constructed next to her home. This trap was designed to catch silt during the winter rains, and in the past, the City of Cape Town would dispatch a “big digger-loader machine and tip trucks” to remove the accumulated silt. This system worked for years. “In 1990, when I moved in here, that used to happen,” Stokes said.

However, she said the system began to deteriorate as the council grew “very slack” and began outsourcing work to contractors, who Stokes said “don’t actually care a thing about looking after council property”.

Over time, the maintenance programme ceased. Stokes said the silt trap was now “completely, completely neglected”.

She said that without a dedicated team, the layers of raw sewage were left for Mother Nature to come along in the winter when rain washed away the top layer, but the heavier silt remained.

Unbearable stench and ecological devastation

The problem, however, is not just silt. According to residents, when the sewage pumping station in St Jones Road failed, it sent “raw sewage” cascading down the canal.

During summer, when water levels are low, the sewage collects in the silt trap and doesn’t get washed away, creating layers of lingering filth.

“The rest of the layers stay here because they’re heavy. So the silt doesn’t wash away. It’s just that the top layer will wash away,” said Stokes.

“In the summertime, the smell is unbearable because it wafts over,” Stokes said, adding that this smell permeated the entire community, including a retirement village in Plumstead.

Malcolm Russell, a resident of the nearby Rathfelder Retirement Village, lives in a unit that overlooks the silt trap in the Diep River Canal. Russell said the smell was a constant reminder of the city’s failure to clean the silt trap.

“When it was very hot, we felt as if we were physically living on a sewage farm. The smell was overpowering,” said Russel.

Russel and Stokes said they had complained and notified the city about the issue many times over the years, but nothing had changed. The canal remained heavily polluted, affecting the community and wildlife such as bird and fish species that once frequented the canal.

Russel said he had witnessed the ecological devastation first-hand. “The fish that were in the canal all died,” he said. He and other residents had to warn unhoused people not to eat the dead fish, which he said were probably killed by “whatever toxics came down in the sewage”.

The once-thriving birdlife, including kingfishers and ducks, has also disappeared. “The fish are dead. The kingfishers don’t come,” said Stokes, lamenting that “the whole ecology is being messed up”.

In the past financial year, from 1 July 2024 to 30 June 2025, there have been six pump station failures, “which did unfortunately overflow into the canal”, according to Zahid Badroodien, the city’s mayoral committee member for water and sanitation.

These were:

• 3 July 2024 – stormwater ingress;
• 9 July 2024 – stormwater ingress;
• 2 February 2025 – generator did not start;
• 12 February 2025 – rising main failure;
• 25 June 2025 – stormwater ingress; and
• 30 June 2025 – generator trip.

Call for urgent action

The residents said attempts to engage the city have been met with indifference. According to Stokes, the silt trap has not been emptied for the past six years. When Deputy Mayor Eddie Andrews came for a site visit a few months ago, he was “so [un]interested”, said Stokes.

However, the city said in response to Daily Maverick that this was not accurate and that a team had been cleaning the trap annually.

Badroodien said that water and sanitation’s catchment, stormwater and river maintenance branch cleaned the trap once a year during the summer when the water level in the trap was at its lowest. This year, they planned to clean it in September.

Russell described how a previous, successful cleaning effort involved putting sandbags across the entrance to the silt trap and using large pipes to divert the water, allowing a Bobcat mini digger-loader to scrape the bottom.

However, he said the city had never managed to return and clean the bottom of the canal after the last pump failure fault.

Residents are now looking for a new solution. Stokes is hoping that a department can be mandated to clean the silt trap twice a year and respond better to sewage spills.

She said that the work needed to be done methodically by an efficient company, not by contractors with “broken-down bakkies and machinery” who “do nothing”.

Badroodien said that a Bobcat machine was still operational and was placed inside the silt trap with the assistance of an excavator and trucks. The last clean-up took place from 1 May to 30 June 2025, from the M3 down to Roscommon Road, he said.

“The city has budgeted approximately R140-million for maintenance this financial year, of which the Diep River Canal will also benefit,” he said.

With regard to the series of pump station failures, Badroodien said preventative maintenance was conducted on the pump stations to avoid sewage spills.

“Sewer network interventions include proactive sewer cleaning, and jetting is now conducted every three months, along with ongoing manhole integrity inspections and the replacement of missing or damaged covers,” he said.

In addition, during this financial year, R1.25-billion will be spent to conduct proactive work to upgrade Cape Town’s sanitation network and pump station infrastructure – including R355-million on sewerage pipe replacements and R214-million in pump station upgrades.

“More than R1-billion was spent on various projects to help bolster proactive efforts to assist with preventing sewer overflows during the previous financial year,” said Badroodien.

In terms of the plan to address the long-term environmental impact of sewage pollution on the canal’s ecosystem, including the death of fish and the departure of birds, Badroodien highlighted interventions planned for the Diep River catchment from the Liveable Urban Waterways programme.

These include:

• Wetland rehabilitation and extension;
• Removal of invasive alien plant species;
• Canal rehabilitation, removal, and renaturalisation;
• Stormwater attenuation ponds to retain water;
• Installation of litter traps and sediment treatment areas;
• Tree planting and landscaping, development of public parks;
• Creation of pedestrian pathways;
• Development of educational spaces and programmes; and
• Provision of recreational opportunities.

Residents told Daily Maverick that all they wanted was for the city’s promises to be translated into concrete action, putting an end to the ongoing ecological and public health crisis they faced. DM