An extraordinary repair

Repairing the only pipeline supplying water to the northern half of Balclutha recently involved ingenuity and extensive health and safety measures due to the tricky location suspended above the Clutha River.

At the same time, the COVID-19 lockdown provided a window of opportunity to undertake the unique repairs while less traffic travelled on State Highway 1.

A methodology was established to build scaffolding down both sides of the Balclutha Road Bridge to construct a working platform in the middle, with a jet ski watching over the crew as part of an appropriate maritime safety plan, Citycare Water Clutha Branch Manager Kerrod Baldwin says.

The valves to isolate the pipe for repair are located in sites subject to significant traffic flow and could only be operated during low traffic volumes – so the reduced traffic during Alert Level 4 lockdown was the perfect timing to schedule the repair, he says.

During the repair a secondary water supply was connected using layflat hoses across the bridge so residential drinking water supplies were unaffected.

On the day of the repair, as a result of the reduced consumption of industrial electricity during lockdown, Contact Energy spilled water from the Clyde hydro dam resulting in the Clutha River rising.

As access to the pipeline had been provided from above, this flood did not affect the repair process, Kerrod says.

The expert Balclutha team carried out the repair safely and the pipeline was reinstated two hours later.

This bespoke repair solution for repairs on Balclutha Bridge is a repeatable process, which will come in handy if further repairs are needed in the future.