Upgrading Rangiora’s water supply

Rangiora’s water supply was upgraded to meet drinking water standards and to improve pressure distribution during peak demand.

The solution was to develop a headworks at Kaiapoi where high quality ground water was available from a borefield. This water would be delivered to a new 4.2ML reservoir at the Southbrook Headworks via an 8.6km, DN500 rising main.

Opus provided high level concept development including pipe material selection, pumping systems, electrical and control systems. We also ran risk workshops and prepared consent applications for pipelines and structures, including detailed landscape architectural design for the Southbrook headworks.

The headworks needed to include a transfer pump station to deliver bulk water via a 3km DN375 transfer pipeline to the existing Ayre St headworks at the top of Rangiora. A distribution pump station at the Southbrook headworks delivers water at a constant pressure to various parts of the reticulation network.

We also managed the tender process for three contracts and provided construction monitoring and administration. Our technical expertise and understanding of local conditions were invaluable to the project.

The project allowed Waimakiriri District Council to discontinue chlorine dosing and make the supply system more resilient. The project came in nearly 8% under budget.

“Well done on a very successful tender process. It is really pleasing to have three contracts let to good contractors and all within budget.” Gary Boot, Project Delivery Manager, Waimakiriri District Council.