Major work starts on Waiwhakaiho stopbanks

Work starts next week on raising stopbanks along the Waiwhakaiho River at The Valley as part of a project to improve flood defences.

The contract for Stage 1 of the three-stage, $1.5 million Taranaki Regional Council project has been let to Taranaki Civil Construction. Stage 1 involves:

• Raising the earth stopbank between Constance St and Vickers Rd, with a retaining wall constructed along a 120m section to avoid encroaching into the river channel.
• Increasing the height of rock-filled baskets (gabion baskets) upstream of Constance St, and between Vickers Rd and the mouth of the Mangaone Stream.

"The work will raise the level of the stopbank by between 0.5m and 1.5m along the entire section," says the Council's Rivers Manager, John Philpott. "The objective is to increase the level of protection from a one-in-50-year flood to a one-in-100-year flood. We've also taken into account the impact of climate change over the next 50 years."

He says the work schedule has been designed to minimise the impact on traffic along Rifle Range Rd, but some disruption is inevitable. "We're sure workers and shoppers at The Valley retail centre will appreciate the need for this work."

The Stage 1 work is expected to be finished in early April. Investigation work has started on Stage 2, upgrading flood protection along the Mangaone Stream downstream of Katere Road, with work planned for late this year.

In Stage 3 of the project, three detention dams will be built in the upper Mangaone Stream catchment to further limit the flow of floodwater into the Waiwhakaiho basin. This work is scheduled for 2012-13.