Wairoa's town water supply reached crisis levels yesterday, causing the town's largest employer Affco to cut its supply last night.
Heavy rain during the weekend caused extremely high levels of sediment to enter the river, meaning the water treatment plant was unable to treat water to the standard required, said
Wairoa District Council engineering manager Neil Cook.
The plant started processing water again about 7am today when the turbidity level - the cloudiness of the water - went below a certain point.
"Prolonged periods of rain mean the river is dirty with high turbidity and that means we can't safely make water," Mr Cook said.
"This rain went on for quite a long time and kept flow rates in the river elevated. A high level of sediment came with that.
"When that happens, one of the first things to go is the Affco water supply.
"There's just not enough water to keep the town and Affco going.
"That's not ideal but that's effectively the policy we follow to protect the health and wellbeing of the town, which comes first," Mr Cook said.
One Affco worker said water was vital to the plant, especially with washing and sterilising while processing.
The meatworks is the town's largest single water-user and its water was cut off at 6pm yesterday, causing the night shift to finish early. Today's chain had not started by 9.30am.
"It's regrettable that Affco have to get cut off. Maybe it is part of what we need to be talking to them about - how we can make that less likely," said Mr Cook.
"Maybe more storage. But that all comes down to dollars."
Some homes experienced low water pressure overnight, he said.
"While the town reservoirs were low, most people around town still had water. We didn't have to put on any water restrictions but we do suggest that people delay washing their clothes for a few days to let the tanks fill up again."
The reservoirs were down to 10 per cent of capacity and the water treatment plant had to wait for the sediment to ease before it could start treating water again.
Mr Cook said it was uncommon for the catchment to remain fully flooded for a long time but every rain event was different.
"This was a long slow one and not high-intensity."
Council operations manager Bill Lewis said several roads were closed by flooding yesterday but rain eased overnight and the roads were open again.
- NZPA
