An alarming number of dead fish in the Milnerton Lagoon last week sparked outrage as residents claim this is due to high levels of pollution.
The City received widespread complaints from residents about worsening foul smells around the Milnerton Lagoon – the stench reaching as far as Table View and Bloubergstrand areas as well.
Residents spotted approximately 500 dead fish, consisting of juvenile mullet species, primarily Southern Mullet (Liza richardsoni), at the mouth of the Milnerton Lagoon on Thursday, 3 March.
The fish have since been collected in the shallows and on the eastern shoreline. The fish were removed for disposal by a team from the Table Bay Nature Reserve on the same day.
Caroline Marx from the Milnerton Central Residents’ Association (MCRA) wrote to the City’s Mayco member for water and sanitation, Zahid Badroodien last week about the stench.
“As reported on Wednesday morning 2 March, there have been widespread complaints about worsening foul smells around the Milnerton Lagoon this week.
Today (3 March) the sandy bed of the Lagoon is strewn with small dead fish, which can only be seen where the incoming tide has caused the murky dark river water to clear. Dead fish have also been spotted on the banks. Your urgent official response as to the cause of this is appreciated,” the letter reads.
Marx further stated in the letter that given the photos and videos of recent non-compliant effluent discharge from Potsdam Waste Water Treatment Works (WWTW), it would be appreciated if the water test results on the actual effluent being discharged is shared with the affected communities.
“This needs to include chlorine and COD levels as heavy dosing of chlorine will reduce the E. Coli levels. However, the non-compliant effluent may still cause major damage to the ecosystem and by overloading the system with nutrients cause toxic algal blooms,” the letter further reads.
The pollution in the Milnerton Lagoon has been an ongoing problem for years. The public group on Facebook, ReThinkTheStink, is holding the City accountable. The group aims to raise awareness and drive change around the alarmingly high levels of pollution in the rivers, vleis and oceans around Cape Town.
The MCRA says in a media statement it notes with deep concern the continued frequent discharges of large volumes of poorly treated effluent from Potsdam Wastewater Treatment Plant into the Diep River over the past months.
“The Erica Road stormwater outlet similarly continues to discharge significant volumes of highly polluted water into the Lagoon except when over-pumping occurs for about seven hours a day on weekdays. Independent water testing shows E. Coli levels of 70 million cfu/100 ml here on 21 February. This together with pump station failures (apparently again on 5 March in Milnerton Ridge) leading to raw sewage spills into the stormwater has led to poor quality river water and widespread recent reports of foul smells,” the statement reads.
The MCRA says such discharges have had a massive detrimental impact on the ecosystem of the river with the virtual disappearance of sand prawns and other aquatic life.
“The fish biopsy results are awaited but it would be disingenuous of the City of Cape Town to claim fish deaths are unexpected. We again request and encourage the City to share both the datasheet of the Potsdam discharges in recent months as well as the Diep River water quality results,” the MCRA says.
Residents last week reported the stench and blamed the City for not caring about the ecology.
A resident says a huge pump can be seen pumping thousands of litres of raw sewage into the vlei. This happens opposite Milnerton High School.
Badroodien says the City is diverting polluted stormwater streams into the sewer where this is technically possible and is manually pumping polluted stormwater into the sewer to lessen the pollution load into the lagoon.
The pumping will continue until the outfall water quality improves.
The City says in a statement that they are investigating the causes of a fish die-off at the mouth of the Milnerton Lagoon.
“The City has initiated an investigation to determine the possible causes of the fish die-off, including an analysis of the water quality. In the meantime, we continue to monitor the situation,” the City says.
