Moutoa floodgates opened to relieve pressure on Manawatū River

The Moutoa floodgates, shown here on the Horizons Regional Council webcam overnight, were opened at 2.05am. Photo / HRC

Horizons Regional Council has opened the Moutoa floodgates to prevent the lower Manawatū River from flooding neighbouring properties after days of rain.

The floodgates on the stretch of river between Foxton and Shannon were opened at 2.05am, Manawatū-Whanganui Emergency Management Group controller Ged Shirley said in a press release.

That diverted water down a spillway which acted as a shortcut to the sea, Shirley said.

“The bottom stem of the Manawatū River is windy and has a relatively shallow gradient, slowing water down. As this happens, the channel fills, risks significantly overtopping a 30-kilometre stretch and flooding adjacent properties.

“Diverting flood flows down the spillway reduces this downstream risk. However, this diversion has no impact on water levels upstream.”

Shirley said there was a “common misconception” that opening the gate acted like a plug, draining upstream and dropping river levels through Palmerston North and the Tararua district.

People who leased land along the spillway had been told on Monday afternoon that the gates could be opened, and had moved stock and dropped fences ahead of time, he said.

Staff monitoring waterways across the region had decided they did not needed to open the Makino floodgates, which protect Feilding.

Although the region has no heavy rain watches or warnings, Shirley asked people to stay prepared, with rain still falling in areas that had already seen “significant inundation”.

He advised people to stay away from low-lying areas and avoid floodwaters, which should be treated as contaminated.

Anyone with flooding should contact their local city/district council.

“Flooded streams and rivers are also dangerous. Currents will be strong and debris such as logs will often be difficult to see.”

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