New insulated pipe for Omakau bridge to be installed for winter

Work will begin on a new insulated pipeline on the Ida Valley - Omakau Road bridge near Omakau during May.

The Central Otago District Council (CODC) Water Services Team approved the project 10 April 2025 and the installation is scheduled to begin 19 May and planned to take up to three weeks.

In the interim, the water services team has confirmed that Fulton Hogan has taken precautions to ensure that the water does not freeze in the current pipe before the works are completed by utilising a system whereby the water is constantly flowing.

Historical data has shown that the previous freeze of the water line followed a consistent five days of frost and -5 degree Celsius temperatures. A 25mm line has been installed on the Ophir side of the bridge to combat this, ensuring that there is always water flow when required. To be clear, this is a controlled restricted flow with a throttled valve that is monitored by the Fulton Hogan team.

The water team is working with the CODC Roading Team, who will be completing maintenance works on the bridge entrances at the same time under a cost sharing approach for Traffic Management, given that this is a substantial cost and the inconvenience for the community because of multiple closures.

The roading team will start the process of getting out notifications and coordinating the traffic management requirements.

The new PE water main with be insulated by utilising an air gap system within a PVC conduit pipe, which is secured to the downstream side of the bridge with brackets. The PVC pipe will be painted for UV protection and to blend in with the metal railing currently along the bridge. The air gap system has shown to provide the same level of insulation as a foam-based system.

The PE Pipe lengths required manufacturing and were ordered following CODC's approval. The manufacturers confirmed yesterday (Wednesday 23 April 2025) that they are now available for delivery on to site from Ashburton.