New website tells Durban if beaches are 'poo' free or not

A University of KwaZulu-Natal scientist has devised an online warning system to tell beachgoers in real time whether it is safe to “come to the sea”.

Woz’Olwandle, meaning “come to the sea” in isiZulu, has been developed by Dr Justin Pringle a senior lecturer and researcher who co-heads the university's environmental fluid mechanics research group.

This comes in the wake of increasing sewage pollution along the coastline, with Durban’s beaches having often demonstrated critically high levels of E. coli — a harmless bacteria found in the guts of healthy people and animals that indicates the presence of faecal matter in the water.

Pollution has been worsened by ageing and vandalised water infrastructure and the April 2022 floods in KwaZulu-Natal, which has severely affected tourism.

The computer model is based on one that UKZN professor Derek Stretch — who co-heads the environmental fluid mechanics research group with Pringle — devised for Durban some 20 years ago with a former student Dave Mardon but was never considered.

The latest model has been repurposed to process data and estimate concentrations of E. coli at six central beaches over 24 hours, using a key of three “smiley” icons in green, orange, or red to indicate whether conditions are “good”, “acceptable”, or “poor”.

The website is hosted on a US server to prevent outages caused by ongoing load-shedding in South Africa.

It uses daily weather and other data from the Global Forecast System which focuses on earth observation, a weather station at uShaka Beach, and results from Talbot Laboratories which regularly gathers and tests water samples.

Pringle told TimesLIVE the need for the website is twofold. “First, after the floods, no one knew the beach water quality status. Second, sampling water takes time (~24 hrs), so it is out of date when this data is reported back to users.

“Hence, a model is needed to plug the gap: giving users real-time and forecast predictions using historical observations as and when Talbot releases them.

“Going live hasn’t changed the water quality from the storm water drains and the Umgeni river. Simply put, raw sewage is coming out of the Umgeni, and we are headed for a cholera outbreak if nothing is done.”

Pringle said he has approached eThekwini municipality to share the model, which has about 2,000 users since it launched in March, but has received no response.

“I am now running the site at my expense and require financial assistance.”

Pringle said he uses laws of physics to predict the transport of E. coli from the Umgeni river and storm water drains along the beachfront.

“We use the wind and rain information from weather stations to predict how much E. coli lands up in the water and where it goes.

“I am hoping that at the very least it will allow people to make informed decisions on where and when to swim.”

Stretch said the potential health benefits to the public “having access to real-time estimates of water quality are obvious, especially given the current and ongoing sewage crisis”.

The functioning of the model needs basic data such as rainfall, wind speed and direction to accurately predict water quality.

“Furthermore, measured water quality data is needed to continually calibrate and verify the model. This data is available from the city, and their support would be very beneficial for the ongoing development and maintenance of this service to the public.

“In my view the private sector beachfront tourism industry should also be involved in supporting this initiative since it benefits their clients.”

Municipal spokesperson Lindiwe Khuzwayo said the city is aware of the website.

“The city makes use of several platforms for sharing such information with everyone. We are open to sharing our information such a water quality reading at our beaches with residents, visitors and stakeholders.”

TimesLIVE

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