Most of the world's 60,000 big dams were designed to last 50 to 100 years

Parts of the Lower Sundays River Canal will face a three-month shutdown for rehabilitation work, the Department of Water and Sanitation (DWS), the Lower Sundays River Water User Association and the Nelson Mandela Bay Metropolitan Municipality (NMBMM) announced Tuesday.

The announcement revealed the closure was scheduled from June 10 to Aug. 15, SA News reported.

The Lower Sundays River Canal is a part of the Lower Sundays Government Water Scheme (LSGWS). The LSGWS canal system provides bulk water to two main groups: agricultural users in the Sundays River citrus area and domestic users in areas like Kirkwood, Uitenhage, Enon and the Nelson Mandela Bay Metro.

This canal is part of the larger Orange-Fish-Sundays Inter Basin Transfer Scheme, which moves 740 million kiloliters of water every year from the Gariep Dam to the Eastern Cape through the 80 km Orange-Fish Tunnel.

The canal needed repairs after a section of it collapsed in May 2017, about 4.4 km south of Enon. To keep water flowing to users, the department built a temporary embankment using a plastic membrane. However, another section of the embankment failed 200 meters downstream from the original collapse.

The DWS, Association and NMBMM explained in a joint statement that "the canal will not be completely shut down, but there will be intervals at which, upon completion of certain segments that are being repaired, water will be allowed to flow through to the dams to supply end users," SA News reported.

It further mentioned that the major domestic users impacted by the closure will be the towns of Addo, Paterson and the Nelson Mandela Bay Metro.

"The reduced supply to the Nooitgedacht WTW [Water Treatment Works] will also be offset by increased supply from the western systems through Loerie and Churchill Dams, and Loerie and Elandsjacht Water Treatment Works managed by Gamtoos Water User Association and the Metro respectively," the DWS, Association and NMBMM noted.

Before the shutdown takes place, the Loerie and Scheepersvlakte Balancing Dams will be filled to 100% capacity and refilled during open flows.

"The department continues to hold meetings with these stakeholders to discuss action plans to mitigate any possible challenges and bottlenecks as the planned shutdown gets implemented," the department said.