CITY OF CAPE TOWN – COASTAL MANAGEMENT: Cape Town’s Fight to Hold the Line
The City of Cape Town is investing in the protection and enhancement of its coastline, in line with nature, for the long-term. A range of projects are underway to sustainably and effectively minimise risks from sand and sea as the municipality battles against waves, wind, storms, and ever-changing climatic conditions.
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Cape Town’s 307 kilometres of coastline stretches from Silwerstroomstrand on the Atlantic side to Kogel Bay in False Bay, and nearly all of it is under pressure. Sea levels here are rising at around 6.3 millimetres a year, almost double the global average, while parts of the city are sinking through subsidence, a combination researchers say significantly amplifies flood and erosion risk. Add a coastline that has retreated by an average of 38 metres since 1937, and it becomes clear why the City’s Coastal Management Department has been racing to protect infrastructure built decades before anyone planned for a rising sea.
Maria le Roux, Head of Coastal Engineering and Optimisation at the City of Cape Town, arrived at the department sideways, having spent the drought years working on subsea pipelines for the city’s temporary desalination rollout. The original brief in the coastal management office was slower and more deliberate: build a strong engineering team, focus on vulnerability assessments and coastal risk planning. “But, because of the situation with things literally washing away, we jumped straight into building capital projects,” she says.
That shift has defined her tenure ever since, and it has taught her just how little room South African municipalities generally have to plan properly. “In South Africa and Africa, for municipalities to look at large developments along coastlines, it is very complex in terms of planning because, apart from all of the risks and variables, there is additional complexity from the dynamic coastline – especially with Cape Town where the coastline is so sensitive from an environmental perspective,” she explains.
Much of that sensitivity is inherited rather than designed. Like most coastal cities, Cape Town’s older neighbourhoods were built hard against the high-water mark long before anyone considered coastal risk or modelled sea-level rise, leaving little buffer between engineered structures and open water. Layered on top of that is a scale of public use few other cities have to accommodate: surfing beaches, promenades, tidal pools and recreational nodes all pressed against the same borderline. “The social component for massive, large-scale coastal protection structures comes with footprints, concrete works, rock revetments, and how you combine that with public and recreational use, which for the City of Cape Town is massive, makes for highly complex and challenging projects,” le Roux says.
Few municipalities elsewhere in the country even have a coastal engineering unit to grapple with that complexity, something she is conscious of every time Cape Town takes on a new intervention. “Many municipalities along South Africa’s coastline do not have coastal engineering unites or even coastal engineers all. We try to share as much information as we can so that contractors and consultants can learn from what we are doing in Cape Town.”
Then there is the winter storms, which answers to nobody’s programme. “I have been involved in projects where you miss a weather window and that’s it; you have to wait another year to start,” le Roux says of the Atlantic seaboard in particular, a coastline she describes as dynamic, storm-prone, and built up so tightly against the sea that “there is no construction space and that is why you often cannot complete major projects in less than three years.”
A SHOWPIECE RISES
Nothing captures that difficulty, or the payoff for working through it, quite like Muizenberg. “We are particularly excited about Muizenberg – this is a once in a lifetime construction project for a metro and it is 100% a showpiece for Cape Town,” le Roux says, a confidence built on seven years of coastal unit groundwork rather than a sudden leap.
Construction on the stepped revetment began in February 2025, replacing the aged, failing seawall along Surfer’s Corner with a three-metre promenade and accessible beach ramp, timed for completion in 2026. Even that schedule has already been squeezed once. “We had to cut the construction period from a comfortable two and half years, down to two years, and then to 20 months, just to ensure we had a buffer with consultants still on their tender term.” It is the kind of project, she says, that only an “amazing team of contactors and consultants” could deliver, and she singles out Guerrini Marine Contractors, who have worked across several of the department’s toughest sites, for particular praise.
Across the water in False Bay, Strand poses an entirely different engineering problem. Where the Atlantic coastline is boxed in by development, False Bay still has room to breathe, which shapes how each structure is designed. “Strand is a one-kilometre gravity seawall and, unlike Muizenberg, it is a vertical seawall and not a stepped structure,” le Roux explains. “We are in the second phase of this historical project with the first phase completed 10 years ago.” Rock revetments in front of the seawall are planned as a future adaptation measure, and climate change is already forcing revisions to the underlying assumptions: shifting wind direction is altering hydrodynamics and sand movement, while drought has disrupted sediment supply. “That is why we are preparing for further work and allowing for future adaptation in all designs,” she notes.
Table View tells a different story again, and le Roux treats it as the clearest proof yet that concrete is not always the answer. When she joined the City, the plan on the table was a large seawall, similar to the one at Sea Point, aimed at stopping sand blowing onto roads and properties nearby. “Windblown sand causes a lot of damage, and it remains an expensive problem in Cape Town,” she says of the original thinking. Her team recommended against it. “We didn’t believe it would work there. We went back to a design that Coastal Management has been working on for years which is to rehabilitate the dunes.”
The results speak for themselves: “It has been a huge success story, and coastal dunes are the best possible defence if you have the space for the sand. It can defend against storm events, it mitigates windblown sand, it promotes biodiversity and recreation, and there are many more benefits.” A three-kilometre stretch of new parking bays and a three-metre walkway have since replaced what was previously just cars parked on sand, and le Roux is unequivocal about where this leaves her thinking. “We are 100% behind design with nature and, anywhere with space, we would recommend this approach.”
SMALLER FIXES
Not every intervention carries Muizenberg’s scale, but each has taught the department something. At Fisherman’s Lane, a road built directly on the high-water mark was partially washed away, a reminder that “every coastal node has its own processes and hazards and there is never a one size fits all solution.” Monwabisi, home to one of the largest tidal pools in the southern hemisphere, offers a different kind of lesson, this one about the long tail of past decisions: a groin and artificial beach built in the 1980s, and modelled at the CSIR at the time, turned out to be the reason that half the road is inundated with sand today. As le Roux puts it, “these developments are not sustainable if you don’t plan them well.”
Small Bay in Blouberg, completed in April, needed a costlier structure than most residential stretches would justify simply because a sewage pump station sat behind it. The sewer lines run through the seawall by gravity. “Now the whole area is home to a large underground structure to protect the road and the services,” le Roux explains, with the road itself designed like a slipway so that any overtopping water rolls harmlessly away rather than pooling against infrastructure. Big Bay and Milnerton took a very different route to the same goal, both built entirely in-house during the Covid-19 lockdown using geo-containers.
“At Big Bay, we had no choice. Gabions, rock revetment, concrete walls would all have taken too long and could have destroyed the beach,” le Roux recalls. Milnerton was meant to retreat the coastline slightly, rarely an option the City can afford to take, “but, again, this was during the Covid period and budgets were cut, storms were coming in, and we needed to act quickly.”
Across every one of these projects, the same pattern has emerged: where there is room to work with the coastline rather than against it, that is the option Cape Town’s engineers reach for first. Hard structures remain essential where space has already run out, as at Strand and Small Bay, but Table View has become the department’s reference point for what is possible when dunes are given the chance to do the job. With sea levels continuing to climb, letting nature share the workload may prove one of the City’s most valuable defences yet.