Willow Place Liner, Queenstown

Queenstown Lakes District Council (QLDC) needed to upsize the pumping station which serviced Kelvin Heights. Unfortunately, the existing 400mm PN6 & PN8 PE pipework could not handle the increased pump pressure so needed to be upgraded. The 700m pipeline ran in a small corridor approx. 5m off the shore line of Lake Wakatipu and along the frontage of the Hilton Hotel. The retaining wall holding up the walk way on the lake edge was also collapsing which meant heavy vehicles and plant could not access the pipeline. H&B’s solution was to line the existing PE pipeline with Amex pressure liner to increase the rating to PN16.

The installation which took one week was extremely challenging due to a number of factors. The existing pipeline was very poorly laid with grade changes and dips of up to 15% with no air valves or scouring points for maintenance. It had not been cleaned in over a decade and the level of contamination we had to remove from the line was extreme. The pipeline was quarter to half full of fat, shingle, rocks and debris for its entirety. This was cleared using a combination of pigging, jetting and robotics. The installation was carried out from either end with minimal disruption to the Hilton Hotel and surrounding residents. The retaining wall to the lake edge was kept intact, the walking track remained open to the public throughout the works and there were no H&S or environmental issues.