Zeekoevlei is utilized by schools and clubs for sailing and rowing, but a harmful algal bloom has resulted in its closure since December.
- Ongoing pollution from the Big Lotus River, along with high temperatures, has led to an outbreak of cyanobacteria (often referred to as blue-green algae) in Zeekoevlei.
- The flower emits a dangerous poison, resulting in the shutting down of the vlei.
- Sailing clubs, crew teams, and educational institutions that utilize the vlei for learning and leisure purposes are now barred from entering it.
- Toxin concentrations in the high-risk category range from 20 to 30 micrograms per liter. The most recent measurements reached as high as 276 micrograms per liter.
Zeekoevlei, a venue utilized by many sailing, rowing, and other leisure clubs, has remained shut since December because of hazardous toxin levels resulting from algae growth.
The harmful substance microcystin is created by a specific kind of bacteriacalled cyanobacteria. It is also known as blue-green algae even though it is not an alga. Fast growth, or 'blooms' of cyanobacteria occur due to high levels of nutrients in water - primarily from sewage pollution and agricultural fertilizers - along with warm weather. Microcystins have severalserious ill-effects on health, including significant liver injury.
Zeekoevlei is an essential component of the City-run False Bay Nature Reserve, and is a listedRamsar Site, which makes it a wetland of global significance.
The Ramsar Convention seeks to conserve wetlands that are "essential for human existence".
However, Zeekoevlei is supplied by the Big and Little Lotus rivers, which pass through areas affected by pollution. The Big Lotus River is the more contaminated one. It originates just south of the Cape Town International Airport and is channelized for most of its path, passing through various informal settlements and small industrial zones, along with farmland in Philippi that is heavily treated with fertilizers.
The vlei has been shut down multiple times in the past because of high pollution levels, such as faecal bacteria, nitrates, and phosphates. In March 2022, GroundUp stated that the extended closure of Rietvlei, and Zeekoevlei, along with other water sources,hit local businessesand stopped the general public, especially kids, and people in canoeing and rowing groups, from participating in water activities.
In August 2023, we reportedthat the City of Cape Town halted recreational fishing at Zeekoevlei due to the fish being "deemed unsafe for human consumption."
The Zeekoevlei Yacht Club, in a communication addressed to the mayor, mentions that the vlei, which is surrounded by Grassy Park, Lavender Hill, and Pelikan Park, serves as an "economic lifeline" for the yacht club and other sporting organizations, along with the nearby neighborhoods.
"It serves as a crucial public asset," the letter states.
The yacht club mentioned that the pollution results from the City's "failure to stop the flow of contaminated wastewater via the Little and Big Lotus Rivers."
"The ongoing closure of Zeekoevlei without the release of public evidence, clear deadlines, and engagement with interested parties highlights significant worries about adherence to these legal obligations," states the letter.
The City has been excavating Zeekoevlei since June of last year to remove "organic-rich sediment from the vlei bed,"statedDeputy mayor and member of the Mayco responsible for urban planning and the environment, Eddie Andrews.
"Enhancing the water quality at Zeekoevlei is among our highest priorities. The dredging process will help eliminate contaminants and boost the general well-being of this environment. The plan is to excavate and take out as much of the nutrient-dense sediment as possible within a span of approximately two years," stated Andrews.
The City's responses to additional questions from GroundUp indicated that the dredging budget exceeds R125-million.
Andrews mentioned that a minimum of two consecutive toxin measurements below 20 micrograms per liter is required before the vlei can be reopened. Presently, readings from 16 February reached as high as 276 micrograms per liter.
The yacht club's commodore, Lara Dugas, stated that the dredging was ineffective unless the continuous sources of pollution were addressed.
Dugas said to GroundUp that the situation "was completely shocking," and it impacted the closure of at least six schools.
Independent freshwater ecologist Liz Day stated that the "ongoing algal bloom and persistent high toxicity levels" indicate that Zeekoevlei's ecosystem is in a severe condition caused by an overabundance of nutrients.
"It's truly a warning that the system requires immediate focus. Many people's means of living rely on accessing the vlei," she stated.
Members of the Zeekoevlei and Rondevlei committee, Sidney Jacobs, stated that the vlei and nearby region are essential for their preserved ecosystem, which is at risk due to ongoing contamination.
Among the roughly 256 native plant species in the region, there are two types of erica that are unique to the area, indicating they do not occur elsewhere.
Zeekoevlei and the nearby nature reserve are also inhabited by 60% of the bird species found in the south-western Cape.
The city's mayco representative responsible for water and sanitation, Zahid Badroodien, stated that the Zeekoevlei catchment area is "one of the city's most intricate and ecologically delicate systems."
Badroodien mentioned that pollution is prevalent throughout the watershed and comes from various sources. He stated that tackling this issue requires ongoing, collaborative efforts instead of single, isolated actions.
Badroodien mentioned that the water and sanitation department, together with many other departments, is working on an action plan aimed at targeting regions that contribute the highest levels of pollution.
He mentioned that the task was "complicated and will require time," although "prompt corrective measures" were being implemented.
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