Ageing infrastructure is the cause of the large sinkhole in Montague Drive and Link Road in Montague Gardens.
The roads have since been cordoned off for repairs after a large sinkhole was reported on 21 August due to a collapsed sewer line, the City of Cape Town has confirmed to TygerBurger.
Based on an assessment of bulk sewers situated in the Milnerton and Blouberg area, the sewer line in Montague Drive was determined to be ageing and has deteriorated due to sulphuric acid corrosion.
The City has confirmed that the extent of the damage is being assessed in order to determine the scope of work required and timelines for repairs. “Repairs commenced this week and are currently under way,” the City’s Mayco member for water and sanitation Zahid Badroodien says.
The recommendation in the assessment report was for the bulk sewer to be rehabilitated. This resulted in the City initiating the Milnerton bulk sewer project as a priority.
The ward councillor in the area, Anthony Bernadie, told TygerBurger that local business owners logged service requests right after the sinkhole appeared.
“I immediately alerted senior management at the roads department, water and sanitation department and senior traffic officers. City teams were on site within 30 minutes. Upon assessment it was found to be a collapsed sewer line. Repair work commenced immediately and is set to continue until full restoration is complete,” Bernadie said.
The City says a contractor was on site to do an assessment of the extent of the damaged sewer line before the actual remedial work can be done.
“This is in the interest of safety as it will also afford the ease of operating the large mechanical equipment during the excavation process,” the City says.
Bulk sewer upgrade project
The collapse of the sewer line happened after the City broke ground on the next phase of the R470 million Milnerton bulk sewer upgrade project, with construction of a new pipeline set for completion by 2025. This project entails the construction of a new bulk sewer in Montague Gardens using micro-tunnelling technology.
The City says the rehabilitation of the bulk sewer will be undertaken in successive phases:
- Phase 1 (March 2023 – Feb 2025) – Minerton sewer project repairs and
- Phase 2 (March 2025 – Aug 2026) – Rehabilitation of the Montague Drive sewer.
Given that the existing pipeline is under the busy Montague Drive roadway, pipe rehabilitation will make use of trenchless technology.
The City will also use a robotic crawler to first profile pipes which will then determine the best method of repair.
All work will occur underground with minimal surface-level disruption to residents and traffic.
Badroodien said last week it was a joy to break ground on yet another major upgrade project.
“The existing bulk sewer under Montague Drive is operating at full capacity, with an upgrade needed to accommodate future growth in this part of the city.
“That is why we are constructing an entirely new bulk sewer, which will operate alongside the rehabilitated existing pipeline.
“The City’s goal is to steadily restore the environmental health of the Milnerton Lagoon through a combination of infrastructure upgrades and dredging of the waterbody to remove pollution build-up in sediment,” Badroodien said.
