17 December 2019
Milnerton lagoon, which is part of the Diep River estuary, is so polluted that the Milnerton Canoe Club is not able to offer a beginner or development programme due to risk of youngsters falling into the water. This is despite the estuary being part of the City of Cape Town-run Table Bay Nature Reserve.
Milnerton Canoe Club chairperson Richard Allen said Lotto funds were available for development programmes, but the club, situated on the Milnerton Lagoon at Woodbridge Island, could not risk children getting sick when they inevitably fell out of their canoes while getting the hang of the sport.
Allen said the club used to have about 20 youths in their beginner programme, but as parents got wind of the poor water quality, they pulled their children out. “The last time we ran a beginners programme was about six or seven years ago. Now we just have a group of about seven kids whose parents are aware of the water quality, but the kids are good enough not to overturn their canoes,” he said.
Allen said not only was the polluted water a health risk, the club spent “many years of arguing and fighting” with City authorities before they eventually provided the results of the monthly water quality tests conducted in the lagoon and the rest of the estuary.
Allen sent the latest results he had after speaking to GroundUp in late November. The results reveal bacteriological pollution levels up to 300 times the national guidelines for intermediate contact, which applies to activities such as canoeing, sailing, or fishing.
The national intermediate contact guideline recommends 1,000 or less colony forming units (CFU) of E.coli per 100ml. E.coli is used as a bacteriological indicator for pollution levels.
But results sent to Allen by the City’s Scientific Services from samples taken on 17 September, reveal E.coli CFU counts of 99,000 per 100ml at the Loxton Road bridge to Woodbridge Island, right in the middle of the Milnerton Lagoon. At the mouth of the Milnerton Lagoon, the E.coli count was five times the limit, at 5,000 CFU per 100ml.
The results clearly reveal pollution enters the estuary through stormwater channels and from the Potsdam Waste Water Treatment Works, as the count at the stormwater outfall from Theo Marais Park – Montague Gardens was 250,000 CFU per 100ml. At the stormwater channel from Bayside Mall the count was 300,000 per 100ml. The Potsdam Waste Water Treatment Works (WWTW) also discharges treated effluent into the Diep River. The results show that the effluent contained 270,000 E.coli CFU per 100ml.
Allen told GroundUp that the lagoon was “particularly disgusting” because “In the summer months there is no flushing from the rain, so we’re dealing with the runoff from Joe Slovo informal settlement and Montague Gardens industrial area”.
He said the rehabilitation of the old wooden bridge to Woodbridge Island, which has just been completed at a cost of R23.4 million, was merely “a bridge over a sewer”. The canoe club had about 30 members, about half of whom were “avid paddlers” and included Springboks and paddlers who regularly won major races.
They very rarely if ever fall out of their canoes and know to spit out any water which splashed onto their faces. However, he said children were regularly found on the beach playing in the lagoon water flowing out to sea. “There is a tiny signboard warning that you swim at your own risk but nobody reads it.”
Beyond the extremely high bacteriological pollution, the fresh water flow into the estuary from Potsdam WWTW via a channel built in 1991, as well as from storm water channels, has led to long-term ecological changes. This is according to a BSc. Honours research paper by Michal Viskich published in 2014.
Viskich’s study revealed “unacceptably high microbial levels” recorded in the lagoon, and a “marked decrease in the number and abundance of invertebrate species”. The permanent fresh water flows from city infrastructure such as the WWTW and storm water channels, had led to “massive changes in sand prawn abundance and distribution in the lagoon”, with sand prawn now only found in sections near where salinity from sea water flow was present. These changes, Viskich noted, had occurred in a “relatively short time period of only 16 years”. The changes and “disturbances” had also led to the “expansion and new introduction of exotic and invasive species” such as the European beach hopper (Orchestia gammarella), the highly invasive mosquito fish (Gambusia affinis) and the invasive reef-building worm (Ficopomatus enigmatica)”.
Head of the Milnerton Central Residents Association’s environment portfolio, Caroline Marx, said she had been dealing with the issue of pollution in the Diep River and Milnerton Lagoon “for the past six or seven years”.
Marx said there are 18 sites in the reserve where the City takes test samples from every month and “some sites are better than others; it depends on where the stormwater drains are”. The monthly tests were only for bacterial pollution, not for heavy metals such as mercury.
She said due to her position in the residents association, she collected the monthly water quality test results, but in order to do so, she had to sign a non-disclosure agreement barring her from sharing the results with the media.
Marx said that this year she had to sign this agreement again after initially signing it some years ago. “Who I can share the results with is not clearly defined, so I don’t share them with anyone in case they leak them to the press. It took me a lot of arguing to get them. I threatened to PAIA (submit a request under the Promotion of Access to Information Act) and the only reason [I got them] is because I’m on the water quality working group in the PAAC (Protected Area Advisory Committee).”
Marx made a proposal to subcouncil that the water quality test results be made available to “all affected parties” and all councillors voted in favour of the motion. Meanwhile Allen said he was happy to share the results as he had never signed a non-disclosure agreement.
Table Bay Nature Reserve Protect Area Advisory Committee chairperson Gordon Laing said the committee was “really concerned” about the water quality in the estuary. He said over three months ago a formal request was made to City to make the results of monthly water quality tests public. “We are still awaiting a response,” said Laing at the end of November.
Since an initial assessment survey of the bulk sewers in Milnerton and Blaauwberg area was conducted in 2015 at a cost of R3.5 million in consultants’ fees, the City has been rehabilitating the system, according to Mayoral Committee Member for Water and Waste, Xanthea Limberg.
She said that to date, the completed projects included: The rehabilitation and upgrade of the Sanddrift bulk sewer at a cost of R70 million; Upgrading bulk sewer in the Joe Slovo/Phoenix area at a cost of R1.5 million; and raising of sewer manholes in the Dunoon sewer outfall so that if the newly built Du Noon No 2 pump station failed, the existing Du Noon bulk sewer surcharges and the existing manholes would no longer overflow and spill into the Diep River Estuary system. This cost R600,000.
Limberg said that the City was nearing completion on a low flow diversion system that would divert stormwater from Joe Slovo/Phoenix to the sewer systems feeding Potsdam WWTW. This is to be completed in December, at a cost of R2 million.
She said other projects in the pipeline were: Diversion of the Du Noon Bulk Sewer to prevent blockages caused by the “ongoing disposal of foreign materials into the existing system. This is expected to be completed by 2020 at a cost of R4 million; a new Montague Drive bulk outfall sewer to be completed in 2026 at an estimated cost of R330 million; and other bulk sewer rehabilitation projects in the Blaauwberg/Milnerton areas, with a budget of R200 million to begin beyond 2026.
She said the agreement “merely requires that the data not be distributed or published without the City’s consent”. An inland water quality report is due to be compiled and completed by March 2020 by consultants who are being paid up to R200,000.
A coastal water quality report, which Limberg’s department last year stated would be available early this year, has yet to be released.