Napier flooding: Incoming rain not expected to 'cause us an issue'

Hawke's Bay regional Civil Defence emergency management group manager Ian Macdonald said the forecast for this evening and into tomorrow was for rainfall rates of about 4mm per hour.

A civil defence expert says rainfall forecast in Napier in the next 24 hours is "not expected to cause us an issue''.

Hawke's Bay regional Civil Defence emergency management group manager Ian MacDonald said the forecast for this evening and into tomorrow was for rainfall rates of about 4mm per hour.

Speaking at a media conference at the Napier fire station, Macdonald said based on the advice from Hawke's Bay Regional Council river engineers, the forecast rain would not cause an issue with rivers.

"They don't consider that to actually cause us an issue. The rivers in Hawke's Bay are perfectly fine, there is lots of room in the rivers in terms of capacity. This was a pretty sudden event in a pretty small area and it's all just surface flooding.''

About 30 people are set to spend Tuesday night at Kennedy Park Resort after being evacuated from their homes.

Napier mayor Kirsten Wise said it was unclear whether any more people would have to join them due to more rain on Tuesday evening.

"Based on the forecasts, which as you can imagine we're following incredibly closely, at the moment we're not anticipating any sort of event to the extent that we had last night," she said.

Asked why the call was not made earlier, to declare a state of emergency, she said there was ''quite a process" to go through.

There had been no warning of the heavy downpour until 12pm on Monday.

The rainfall had peaked at 6pm, and the state of emergency was declared at 8pm.

She said the standard state of emergency period was seven days, but that could be shortened depending on the next few days.

She said it was testament to the support provided to residents that no one was hospitalised as a result of the flooding.

"I'm not aware of anyone that was hospitalised.''

Anyone who felt unsafe or considered their welfare to be at risk should call 111.

Asked whether the Napier City Council should face scrutiny over the performance of the town's stormwater system, Wise said it was expected to cope with a one in 100-year event.

"What we are currently regulated on, is being able to provide infrastructure that can cope with a 1 in 100-year event. This was a one in 250-year event.''

Wise said that with ''change in our world, climate change and other factors" the council needed to consider whether there would be more flooding events and "do we need to invest in our infrastructure for the future".

The council had chose to relieve pressure on the system by discharging contaminated water into a stream feeding into Ahuriri estuary.

Wise said her understanding was that any sewage contamination of floodwaters on Napier streets was diluted.

"With the volume of water that we had ... I have been advised it is heavily diluted by the time it is discharged to the streets."

Hawke's Bay District Health Board medical officer of health Nick Jones said people should avoid contact with the floodwaters if possible.

"We would counsel against people playing in the water.''

Dean Clifford from the New Zealand Police said if any of their staff assessed a need for a road closure, they can take immediate action to prevent danger as they see it driving around.

Both residents and retailers in Napier have pointed out repeatedly that the bow waves caused by vehicles driving through flooded streets have caused damage to their properties.

"If theres a need to close a road, I'm sure that will be done pretty much automatically.

Clifford said police would work with council to get contractors in where more permanent barriers are required.

"It's more likely that we may de-escalate and open some roads up that have been closed during the day as the water recedes."