$750,000 damage to flood protection systems

Severe rainfall and flooding throughout the Wellington Region in the first week of January caused an estimated $750,000 damage to flood protection systems, Greater Wellington Regional Council says.

The Hutt, Waikanae and Otaki rivers were all affected. Preliminary damages estimates are around $450,000 for the Hutt, $120,000 for Waikanae and $210,000 for Otaki.
The Hutt River peaked around 1527 cumecs at Taita Gorge (a 25-year return period) while the Akatarawa River had an 80-year return period and Whakatikei River had a 60-year event. The Waikanae River experienced an 80-year return period (381 cumecs) while the Otaki River had a 40-year event (1574 cumecs).

“Although our flood protection works generally held up well against the deluge, we will need to repair bank edges, stopbanks and willow lines. Several property owners are also asking us for support and advice about measures they can take to protect their land,” says Greater Wellington Landcare Committee chairperson Chris Laidlaw.

“It’s important to remember that we can only do so much to control the forces of nature in flood plains,” said Cr Laidlaw. “But our defensive systems are getting better all the time and that’s encouraging. This flood would have caused a lot more damage five or ten years ago.”

Greater Wellington staff have been assessing the damage and meeting with affected parties since the floods of 6th January.

“We’re working with local councils, such as Kapiti Coast District Council (KCDC), to discuss further options and solutions with landowners. At Otaihanga, where some houses were flooded, KCDC and Greater Wellington will be meeting with landowners to discuss issues such as flood warning systems, gravel extraction within the river system, and the possibility of house-raising.”

Staff are investigating why water got onto the wrong side of the Waikanae flood wall and may look at making some changes to the design.

On the Hutt River, similar flood damage repairs will be required but there was only minor damage to the major new works being constructed in the Ava-Ewen stretch.

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