Timaru District Council’s Pareora pipeline renewal project is making good progress despite challenging weather conditions and difficult ground conditions causing slight delays and putting the expected completion date of the project at September 2024.
The Pareora pipeline renewal is a series of major physical works undertaken to secure Timaru city’s main water supply while protecting internationally significant cultural heritage. Running approximately 37 kilometres from the Upper Pareora Gorge in the Mackenzie District to Claremont on the edge of Timaru, this critical piece of infrastructure passes through areas of cultural significance to mana whenua and New Zealand’s highest concentration of extant Maori rock art.
“The existing 90-year-old pipeline is still an impressive bit of engineering.”
Installed in the 1930s, the Pareora pipeline is a critical component of the Timaru water supply, providing the bulk transfer of raw water from the Pareora River intake to the Claremont water treatment plant and storage reservoirs. This source provides approximately 60% of water consumed in the Timaru supply on an annual basis.
Numerous sections of the pipeline were in poor condition and leaking. The renewal of the pipeline is necessary to ensure the continuity of the Timaru water supply and minimise water loss. Timaru District Council Principals Three Waters Specialist Grant Hall says the pipeline renewal is a three-stage project with sections one and three being completed and commissioned in 2022.
The most technically challenging section two through the gorge is still underway by Hadlee and Brunton. They are working in steep and undulating terrain with arable and mixed-stock farmland. “The existing 90-year-old pipeline is still an impressive bit of engineering, as it transports water from the river intake, through the gorge and all the way to Timaru without needing pumps,” Grant says.
“While the whole job is challenging, getting the water through the gorge was particularly difficult, so while a majority of the pipeline will be new, we’re also adopting an innovative liner technology to reuse the current pipe. Our forebears knew what they were doing, and they picked the best route through the gorge, so we’d be foolish to abandon it.”
“The proven liner technology enables us to continue benefiting from this route, while ensuring the pipe is good for decades to come and lessens our impact on a culturally significant area.”
Recent progress on section two includes the completion of the Wetlands Stage near its west end. Then an urgent water main upgrade required in Timaru meant resources had to be diverted, and the project’s completion date was pushed out by several months. About 2,440 metres of 4.3 kilometres of the pipeline have to date been either lined or replaced by open-cut excavation.
A total of 2,140 metres has been lined with the Amex pressure lining system, while 300 metres of open-cut excavation used DN450 PE100 PN10 pipe through a wetland and an area with an active slip zone. A further 1,865 metres of lining is scheduled to be installed from March through to September 2024.
This timeline is weather-dependent however the contractor and the Council have been able to accelerate the programme by arranging longer shutdowns of the main and relying on Timaru’s alternative source of water supply.
© Waterford Press Ltd 2024 – Independent Print Media New Zealand
