On 14 November 2019, the City of Cape Town banned windsurfing at Rietvlei due to a "bloom" of blue-green algae. Rietvlei is host to the largest windsurfing club in South Africa. This ban has been instituted despite the fact that the water quality at Rietvlei meets all international and national standards for conducting watersports.

The Milnerton Aquatic Club, the largest sailing club in Cape Town formed in 1976 is unsustainable without windsurfing members. It is the only safe place within Cape Town proper for beginners to learn windsurfing. A similarly-unjustified ban in 2017 almost caused the collapse of the club and if this ban is not ended soon, the MAC could disappear. 

What is Blue Green Algae?
Blue-green algae, or cyanobacteria, are naturally occurring bacteria that are common all over the world in freshwater lakes. High concentrations of the algae forms "blooms" which manifest as a blue-green scum that looks like a paint spill.

Most blue-green blooms are not toxic but some produce toxins that can, in very rare cases, be harmful to humans. People swimming through algal scums may experience skin rashes or upset stomachs and nerve and liver damage are possible from infected water used as a long-term source of drinking water. Notwithstanding the City's alarmist notice referencing risk of death, there are no recorded human fatalties from ingestion during watersports.[1] Recorded health issues are limited to headaches, nausea, fever, flu symptoms, muscular pain, diarrhoea, pneumonia, vomiting, skin rashes, mouth ulcers and eye or ear irritations.

What is the Standard for Managing Recreational Waters?
South Africa has its own recreational waters standards.[2] The City of Cape Town does not apply these but instead applies the World Health Organisation Guidelines for Safe Recreational Water Environments ("WHO Guidelines"), which are considered to be a global standard. The standards in relation to blue green algae are summarised at page 16 of this document: https://fas.org/sgp/crs/misc/R44871.pdf .

They provide that at concentrations of microcystin of:

1. less than 10 micrograms per litre, no action is required;
2. between 10 and 20 micrograms per litre, on-site risk advisory signs should be posted;
3. between 20 and 2,000 micrograms per litre, swimming should be banned;
4. more than 2,000 consideration should be given to prohibiting watersports.

What Happened in 2017?
In 2017, the City closed Rietvlei to all watersports justifying the closure on the basis of the presence of microcystin in the water and the WHO Guidelines. After months of the vlei being closed, a MAC member discovered that the City was applying the incorrect WHO Standards. They were applying the WHO Drinking Water Standards (for the management of drinking water) and not the WHO Recreational Water Guidelines. The City refused to share its test results, but was eventually forced to do so through an access to information application. This revealed that the City had not recorded any of its deliberations around closure and was unable to produce a single test result that exceeded a 9.30µg/l. Faced with legal action, the City eventually reopened the vlei.

Current Situation
On 14 November 2019, the City announced a ban on windsurfing, canoeing, paddling and water skiing (but not any other water sports) via a notice stating that "current levels of toxins … within the vlei necessitates (sic) this precautionary approach. The toxin levels are categorised as Moderate: Exposure Risk (sic) as per the World Health Organisation (WHO) guidelines and holds the risk of long-term health implications with exposure."

Once again, the City has refused to share its test results, but we believe that at the time of the Notice, the concentrations were at the Relatively Low level. The Notice is therefore a misrepresentation of the truth in that:

1. the WHO Guidelines do not necessitate prohibition of windsurfing at Moderate Risk level;
2. the Risk Level at the time of the Notice appears to have been "Relatively Low" and not "Moderate";
3. The WHO Guidelines currently only recommend the posting of advisory signs (which has been done);
4. If the levels increased over 20µg/l, the WHO Guidelines recommend that swimming should be banned (it already is by law);
5. the WHO Guidelines would not recommend considering a windsurfing ban until the concentration level exceeded 2,000µg/l;
6. an overly cautious approach is not consistent with the WHO Guidelines;
7. the risks for the Moderate Risk level are overstated by the City.

What do we Want?
(1)   Unban Windsurfing at the Lake Immediately
The City should be going about its task scientifically and making its decisions rationally based on international best practice. The WHO Recreational Guidelines set out succinctly the role of the City.

It is -
"not to deter the use of recreational water environments but to ensure that they are operated as safely as possible in order that the largest possible population gets the maximum possible benefit. The adverse impacts of recreational use of coastal and freshwater environments upon the health of users must be weighed against the enormous benefits to health and well-being - rest, relaxation and exercise - associated with the use of these environments."

The water is currently safe and windsurfing should be allowed.

(2)   Implement the WHO Recreation Guidelines Going Forward
It is important that the City adopts a rational, consistent approach to regulating recreation at Rietvlei. The City must adopt and publish standards and apply them consistently. It must also educate its officials so that they interpret the standards properly. The WHO guidelines are an appropriate standard to adopt.

(3)  Take Steps to Get Rid of the Grass and Algae
The City must actively manage the water and must take steps to get rid of the water grass and weed growing around the banks of the Vlei and physically break up the algae scums. The City has an obligation to make sure that the maximum number of people derive the maximum benefit from the Lake.

Thanks for reading this far. Please help us get support for this petition by sharing it on social media and with your friends. We have a meeting with the City on Thursday 21 November and would like as many signatures by then as possible.

[1] Paragraph 8.73 of the WHO Recreational Water Guidelines.
[2] South African Water Quality Guidelines, Volume 2 – Recreational Use.