The eThekwini municipality is spending R1.2-billion to replace a 24-km pipeline that is more than 70 years old and has exceeded its 50-year design life.

eThekwini municipality’s Water and Sanitation Unit project executive Sduduzo Mtshali explains that the Southern Aqueduct has been supplying water to about 1.2-million people through 33 reservoirs and, owing to wear and tear, is no longer performing optimally.

He states that the Southern Aqueduct was originally constructed as a twin pipeline made of steel and concrete. However, one pipeline had deteriorated to such a degree that engineers had to decommission it, which had resulted in water rationing in some areas.

“Currently, only a single pipeline is operational and, with growing water demand, its capacity is no longer sufficient. Having only one pipeline is a significant vulnerability, as there is no fallback option when repairs need to be carried out,” Mtshali said.

The decision to invest in replacing the pipeline was taken in early 2024 and the project was launched in April that year.

An oversight visit by eThekwini Mayor Cyril Xaba on June 11 revealed that the first two work packages are now 50% complete.

The Southern Aqueduct project involves replacing the 975-mm-diameter concrete pipeline with new steel pipes ranging from 1 000 mm to 1 600 mm in diameter to enable greater flow capacity.

The project is divided into eight work packages.

Work Packages 1 and 2 started in 2024 and are almost complete. The construction of a new 1 200-mm-diameter steel pipeline from Shallcross road to Chatsworth Reservoir was undertaken in Work Package 1.

Work Package 2 involved the installation of a 1 400-mm-diameter steel pipeline from Shallcross to the Northdene area.

Work Packages 3 to 6 started in April this year, with pipeline installation under way from Northdene through Paradise Valley Nature Reserve and Westville and ending in Reservoir Hills at the Durban Heights Water Treatment Works.

The construction team is employing innovative methods, including pipe jacking; a trenchless technology used to install underground pipelines without extensive surface excavation.

To help prolong pipeline lifespan, the project includes a viscoelastic corrosion protection coating with zero cathodic disbondment and self-healing properties.

Additionally, a cathodic protection system is being implemented to provide secondary corrosion resistance owing to severe stray currents stemming from nearby high voltage overhead power lines and electrified railway lines.

“As eThekwini municipality, our priority is the delivery of reliable water infrastructure. Once the new pipeline is operational, many of these losses will be eliminated, ensuring a more reliable water supply to our communities. “In addition, the construction of the Umkhomazi dam by uMngeni-uThukela Water will augment raw water for the city and further improve its water situation,” Mtshali said.