Everything about the water infrastructure being installed in Frimley is large-scale – from the large diameter polyethylene pipes and the drill rig installing them, to a massive five-tonne pipe connector.
The pipe-laying is one of a number of significant projects in the Hastings Drinking Water Strategy either completed or underway, designed to improve drinking water safety and add capacity and resilience to the district’s water network.
Fulton Hogan has been contracted by Hastings District Council to complete the pipe installation, project managed by the company’s Three Waters Department manager Joe Symonds.
The pipes (500mm striped for raw water; 560mm and 630mm blue for drinking water) have been fusion welded together, doing away with traditional ‘joints’ that were a weak point in traditional pipe materials. Using HDPE removes the risk of contaminants getting into the water system through joins, and the pipes have seismic resistance during earthquakes, giving the network resilience and strength.
A drill rig set up on Frimley Rd is boring the hole underground for the pipe, through which the pipe will be drawn back. Using this technique means the need for long disruptive stretches of open trenching is avoided, minimising disturbance and reinstatement costs.
But the connections still require major excavations. The six-metre by six-metre hole at the intersection of Nottingley Rd and Frimley Rd is where a five-tonne ‘three-legged’ connection detail, measuring approximately four metres by four metres, will be installed. It will sit atop a 150-tonne concrete anchor block.
It will be moved into the hole in about two weeks, after which it will be connected to the new and existing pipes, the hole filled, and the road and roundabout reinstated. “All up, about another seven or eight weeks, depending on weather and ground conditions,” said Mr Symonds.
Further into the project, connections will also be required at the Frimley Rd intersection with Hapuku St, and where the pipes to and from the new water treatment and storage facility will join onto the water main.
Hastings District Council’s Frimley project manager Herman Wismeyer said the two main parts of the project – the pipe work and the storage and treatment facility – were proceeding well.
Construction of the treatment and storage facility got underway last week after the Resource Consent process was completed. “While the pipe work alone would have improved the network, by having both parts of the project we achieve those aims around water safety, capacity and resilience to a far greater level.”