Urgent repairs to Nagle Dam-Durban Heights WTW Aqueduct 3: From Tuesday, 5 July 2022, to Monday, 11 July 2022

Urgent repairs to Nagle Dam-Durban Heights WTW Aqueduct 3: From Tuesday, 5 July 2022, to Monday, 11 July 2022

STATEMENT: Urgent repairs to Nagle Dam-Durban Heights WTW Aqueduct 3: From Tuesday, 5 July 2022, to Monday, 11 July 2022

Friday, 01 July 2022

A leak has occurred in one of the four Nagle Dam-Durban Heights Water Treatment Works (WTW) raw water pipelines, necessitating urgent repairs to do be done in order to prevent a potential hazardous situation. The leak is on Aqueduct 3 in the vicinity of Annet Drive, Reservoir Hills, Durban, which has worsened over the past three months, from a drip to a constant flow that is visible by passers-by.

Similar to the other three aqueducts, this is a high-pressure pipe that coveys large volumes of water for treatment at the plant. In interest of public safety and to prevent further water loss, Umgeni Water has taken a decision to shut down Aqueduct 3 from the morning of Tuesday, 5 July 2022, so that this essential work can be undertaken. In terms of the work schedule provided by the contractor, it will take six days for the repairs to be completed, which includes a day for draining and drying of the inside of the pipe. This means that the pipe will begin receiving water again from Monday, 11 July 2022. Umgeni Water has informed Ethekwini Water and Sanitation of the urgent nature of the work and of its duration.

Aqueduct 3 conveys, on average, 180 million litres (Ml/d) of raw water daily from Nagle Dam to the Durban Heights WTW. During the shutdown, there will be a reduction in the amount of treated (potable) water Umgeni Water normally supplies to EThekwini Water and Sanitation. Similarly, due to reduced volumes of raw water reaching the plant and potable water being produced during the period when Aqueduct 3 will be offline, it may not be possible to maintain the on-site Reservoir 2 at a minimum of four (4) metres.
This level is required for there to be sufficient head pressure to supply Ethekwini Water and Sanitation’s reservoirs in high-lying areas, particularly in the South of Durban. Therefore, consumers in Umlazi, Chatsworth, Northdene and surrounding areas are likely to experience low pressure or intermittent water supply.

Umgeni Water wishes to apologise for any inconvenience that may be caused.
At this stage, aqueducts 1 and 2, which were severely damaged in the April 2022 floods, remain decommissioned while awaiting completion of repair work on them. As a consequence, Umgeni Water is using three and intermittently the fourth emergency shaft pumps to transfer water from Inanda Dam to the Durban Heights WTW, as an augmentation measure. To mitigate possible risk of failure, the fourth shaft pump is brought into use for five (5) days in a week, thus allowing it rest period of two (2) days. In the period in which the shaft pumps are used, the full required volumes of raw water reaches the plant for treatment; conversely, a deficit occurs in the remaining two days.

At this stage, replacement of the 180 million litres of raw water that will be temporarily lost from Aqueduct 3 is not possible due to implementation of available contingency measures. Umgeni Water provides an assurance that everything possible will be done to try to complete the work on Aqueduct 3 within or even before the allocated timeframe.

There are significant benefits to restoring Aqueduct 3 in the shortest possible period. This includes increased volumes of raw water being conveyed through it, thereby further reducing the shortfall in raw water. As this deficit reduces, more drinking water will become available for supply to Durban.

Corporate Stakeholder Management Unit, Office of the Chief Executive