Flood barrier installed in Whanganui's Kowhai Park as a precaution after day of heavy rain

Horizons Regional Council's Ged Shirley said a water barrier was installed in Kowhai Park last night as a precaution for potential flooding. Photo / Bevan Conley

A flood barrier was installed at Kowhai Park on Monday night as a precaution against possible major flooding from the Whanganui River.

Horizons Regional Council emergency management controller Ged Shirley said the decision to install the water-inflated barrier was made late on Monday afternoon and Horizons roading crews had the barrier fully installed before 7pm.

Shirley said Horizons' modelling of water levels suggested the high flow of the Whanganui River, combined with a king tide and a storm surge, could have resulted in the river breaching flood banks at the park.

"Luckily, the way things eventuated at high tide later in the evening, that wasn't needed," Shirley said.

Shirley said the storm surge didn't end up affecting river levels very much as wind speeds dropped overnight.

However, the barrier was still in place this morning and a decision on when to remove it would be made after the river reached high tide.

MetService meteorologist April Clark said a council weather station in the Whanganui hill country recorded 14mm of rain between 7pm and 8pm on Monday.

A weather station at Kauangaroa on the Whangaehu River recorded 9.5mm of rain between 7pm and 8pm, and 15mm over 24 hours.

Whanganui Airport recorded 6mm of rain over 24 hours, as well as wind gusts of up to 96km/h.

Across the region, although a lot of water was in river systems, Shirley said river levels should have peaked this morning, with thunderstorms subsiding.

Clark said there was only a low risk of thunderstorms across Whanganui today, with showers expected to become more frequent and heavier in the evening.

"There are still some showers around, but nowhere near as active as we've seen in the past few days, so we're slowly on the easing trend," she said.

She said strong winds were expected today, with potentially gale-force gusts in exposed areas.

Clark expected the rough weather to ease going into tomorrow and the rest of the week, with only isolated showers remaining.