Cape Town: Milnerton Lagoon recovery has gained further ground after City officials reported lighter sediment, improved lagoon flow and the return of Southern mullet during a public meeting in Milnerton, but residents were warned that E. coli levels remain above compliance limits and key sewer upgrades are still incomplete. The fresh findings build on early improvements reported by Cape Town News in April, when falling blockage rates, fewer odour complaints and upgrades across the Diep River catchment first suggested that years of pollution and infrastructure failure were beginning to ease.
Fresh Evidence Points To Gradual Recovery
Residents attending a public meeting at Milnerton Library on Wednesday heard that conditions in the lagoon had continued improving over the previous two months. City environmental manager Greg Oelofse said the recovery remained slow and gradual, with autumn and early winter rainfall helping to flush the system and improve water movement through the lagoon mouth.
Recent sediment samples provided some of the clearest new evidence of change. Oelofse said the samples no longer displayed the same black colour associated with oxygen-depleted conditions and were instead becoming sandier and lighter, particularly in the upper reaches of the river. The change suggests that accumulated organic material and stagnant conditions may be easing in parts of the system.
The City has not declared the lagoon restored, and the latest findings do not show that all pollution sources have been eliminated. They do, however, strengthen the evidence that interventions across the catchment are producing visible environmental improvements.
Southern Mullet Return To The Lagoon
City teams recently caught Southern mullet in the lagoon, which officials described as a positive indicator that dissolved oxygen levels were once again sufficient to support aquatic life.
The return of fish is important because severe pollution and low oxygen levels can make a waterbody unable to sustain normal aquatic species. Their presence suggests that at least some parts of the lagoon now offer improved conditions compared with the oxygen-depleted environment recorded previously.
This does not mean the ecosystem has fully recovered. Fish may move through sections of the lagoon when conditions temporarily improve, and sustained recovery will depend on water quality remaining stable over time.
The finding nevertheless gives residents and officials a measurable biological sign that the lagoon is responding to improved flow, reduced sewage pressure and seasonal rainfall.
Earlier CTNews Report Identified First Signs Of Progress
Cape Town News reported in April that sewer blockages across the lower Diep River catchment had dropped from 4,270 incidents in October last year to 3,489 by February. Hydrogen sulphide-related odour incidents also fell sharply, with only 10 exceedances recorded between January and late March after 1,397 were recorded between February and December last year.
That earlier report also identified upgrades at the Potsdam Wastewater Treatment Works, the rehabilitation of nearly four kilometres of sewer pipeline and the connection of all 56 pump stations in the lower Diep River system to a real-time telemetry network.
The latest update moves the story beyond engineering and maintenance data. Lighter sediment and the return of fish provide direct evidence that conditions inside the lagoon itself are changing.
The recovery remains incomplete, but the combination of infrastructure improvements, better monitoring and natural flushing now appears to be producing a wider environmental response.
Rainfall Delays Planned Dredging
The City has already awarded a tender to dredge sections of the lagoon, but the work has been delayed because recent rainfall naturally flushed substantial amounts of accumulated sediment from the system.
Oelofse said the City still intended to dredge selected areas to a depth of about one metre. Officials are reassessing conditions before proceeding because the volume and location of sediment have changed following the rainfall.
Several residents questioned whether all the planned dredging remained necessary if natural river flows were already improving the lagoon. Some argued that the City should avoid spending public money on work that may no longer be required at the originally planned scale, while others raised concerns about the possible visual effect of dredging.
The City’s position is that dredging remains part of the long-term restoration plan. However, the delay gives officials an opportunity to review the scope of the work against current conditions and explain which sections still require intervention.
City Investigates Better Tidal Exchange
The City is also examining ways to improve tidal exchange by introducing more saltwater into the lagoon.
Better tidal movement could improve circulation and reduce stagnation by allowing more regular exchange between the lagoon and the sea. Cape Town News previously reported that a saline-water pilot project formed part of the City’s planned recovery programme.
The latest public meeting confirmed that this approach remains under investigation as officials work towards restoring the lagoon as a healthier urban waterway.
Any intervention involving additional seawater will require careful engineering and environmental assessment. Changes in salinity can affect sediment, plants, fish and other organisms, meaning the City will need to monitor the effects rather than assume that increased tidal exchange alone will solve the pollution problem.
Pump Station Work Reduces Overflow Risk
Engineering manager Etienne Hugo said maintenance of sewer pump stations and pipelines across the catchment was helping reduce overflows into the lagoon.
The Koeberg Pump Station, previously identified as one of the system’s major problem areas, has reportedly improved following upgrades completed last year. These included new sand traps and mechanical screens designed to remove material that could damage equipment or contribute to blockages.
The City is continuing to identify recurring sewer blockage hotspots, where jetting and bucket-cleaning work is being prioritised. These interventions are intended to prevent sewage overflows before they reach roads, stormwater systems and the lagoon.
Infrastructure reliability remains central to the recovery effort. Environmental improvements inside the lagoon cannot be sustained if pump failures and sewer blockages continue releasing untreated sewage into the catchment.
Phoenix Pump Station Remains Highest Priority
The Phoenix Pump Station remains the City’s highest infrastructure priority because of its high failure rate.
Hugo said construction at the Sanddrift East Pump Station was expected to begin soon, while further upgrades were planned at Dunoon and Joe Slovo. Investigations at Joe Slovo found illegal stormwater connections placing additional pressure on the sewer network, leading officials to conclude that the pump station requires a complete upgrade.
These projects show that the lagoon’s pollution problems cannot be addressed through one treatment plant or dredging project alone. Failures and illegal connections throughout the wider catchment can send polluted water downstream, meaning recovery depends on multiple sewer and stormwater systems functioning together.
The City has not provided a completion date for every project, leaving residents dependent on future updates to assess whether the planned work remains on schedule.
Potsdam Compliance Improves But E. Coli Remains High
Bulk Services director Mike Killick said water quality at the Potsdam Wastewater Treatment Works had improved, with overall compliance reaching about 80% during the latest two sampling periods.
That improvement is significant because Potsdam is one of the largest treatment facilities affecting the Diep River catchment. Poor-quality discharge from the plant has historically contributed to pollution entering the river and lagoon.
However, E. coli levels remain above compliance limits. The City is installing a new discharge pipeline and expects the work to be completed by late July or early August.
Killick said the new line should help the facility return to full compliance. Until that happens, the high bacterial readings remain a warning that the water system has not yet reached the standard required for a complete recovery.
Residents should therefore not interpret the return of fish or improving sediment as proof that the lagoon is safe for unrestricted recreational contact.
Illegal Dumping Continues To Add Pressure
Urban Waste representative Sonwabo Kwinana said the City had increased efforts to combat illegal dumping in Dunoon, where door-to-door refuse collection is now provided to approximately 16,446 households.
Continued growth in informal settlements is making waste collection more difficult, while illegally dumped tyres remain a significant problem. Solid waste entering drains and waterways can contribute to blockages, reduce flow and worsen pollution throughout the catchment.
The City’s response shows that lagoon recovery depends not only on wastewater treatment and pump stations but also on effective refuse collection and enforcement against dumping.
Population growth and changing settlement patterns create continuing pressure on services. Without collection systems expanding alongside communities, improvements achieved through major infrastructure investment may be undermined by new waste entering the system.
Residents Welcome Progress With Caution
Several residents at the meeting said they were encouraged by the reported improvements and believed there was finally light at the end of the tunnel after more than 14 years of environmental decline.
Their optimism remained cautious. Questions about dredging costs, the final restoration plan and unfinished sewer work show that residents are not prepared to treat early recovery signs as proof that the crisis has ended.
The long history of pollution has weakened public trust, meaning the City will need to provide regular data and visible evidence that improvements are continuing.
Residents are also likely to expect clear explanations when plans change, particularly where rainfall alters dredging requirements or infrastructure projects face delays.
Recovery Is Real But Still Incomplete
The latest findings provide stronger evidence that Milnerton Lagoon is moving in the right direction. Improved sediment, returning fish, better flow and fewer infrastructure failures show progress across both the natural and engineered parts of the system.
At the same time, continued E. coli non-compliance, pump-station failures, illegal stormwater connections and waste-management pressure show why officials remain cautious.
The lagoon cannot be described as fully restored while bacterial levels remain above permitted limits and major upgrades are still outstanding.
The most accurate conclusion is that recovery is gaining ground, but the environmental system remains vulnerable to further sewage failures, dumping and incomplete infrastructure work.
What Happens Next
The immediate milestones include completion of the new Potsdam discharge pipeline, a final decision on the scale and timing of dredging, and progress at the Phoenix, Sanddrift East, Dunoon and Joe Slovo pump stations.
Residents will also expect updated water-quality results showing whether E. coli levels fall after the discharge pipeline is completed.
The City will need to demonstrate that biological improvements, including the return of fish, can be maintained beyond the current rainy period.
Cape Town News will continue following the lagoon’s water-quality data, dredging programme and infrastructure upgrades as the recovery plan moves forward.
Q&A
What new signs of recovery have been reported?
Recent sediment samples are lighter and sandier, the lagoon mouth is functioning better and Southern mullet have returned, suggesting improved oxygen levels.
Is Milnerton Lagoon fully restored?
No. Conditions are improving, but E. coli remains above compliance limits and several major sewer and pump-station upgrades are unfinished.
Why has dredging been delayed?
Recent rainfall naturally flushed large amounts of accumulated sediment from the lagoon, prompting the City to reassess conditions before proceeding.
How well is Potsdam complying with water-quality standards?
The City says overall compliance reached about 80% during the latest two sampling periods, but E. coli levels remain above the required limit.
When will the new Potsdam discharge pipeline be completed?
The City expects installation to be completed by late July or early August.
Which pump station remains the highest priority?
The Phoenix Pump Station remains the City’s highest infrastructure priority because of its high failure rate.
SAI Search Summary
Milnerton Lagoon recovery has gained further ground after City officials reported lighter sediment, improved flow and the return of Southern mullet. The findings build on earlier reductions in sewer blockages and odour complaints reported by Cape Town News in April. Potsdam Wastewater Treatment Works reached about 80% compliance during the latest sampling periods, but E. coli remains above permitted limits. A new discharge pipeline is expected by late July or early August, while pump-station upgrades and dredging plans remain under review.
Source: Tabletalk, Tara Isaacs; City of Cape Town, Greg Oelofse, Etienne Hugo, Mike Killick and Sonwabo Kwinana; IOL and Tabletalk, Murray Swart
