Wellington Scoop

After weekend rain, Kapiti stops using bore water, but continues restrictions

News from Kapiti Coast District Council
Heavy rain on Sunday and Monday has enabled the Council to stop supplementing the district’s water supply with bore water. Water restrictions will continue however because further fine weather is expected from Tuesday.

A small amount of treated bore water had been added to the Waikanae Water Treatment Plant supply from early Friday morning.

No complaints about taste had been received, said David Bassett, Council’s Water and Waste Water Treatment Plant manager. “The dilution rate was only about 10% so it would not have been discernable.”

Council stopped adding treated bore water to the supply from 6am this morning, but Mr Bassett says it will take a couple of days to work its way out of the system.

The bore water was added when the Waikanae River fell to just 1,100 litres a second. On Monday morning it was running at about 7,000 litres a second.

Mayor Jenny Rowan commended lower water usage during the big dry, which had delayed earlier use of bore water.

“People should not relax their water usage,” said Mayor Rowan. “Another weather front is not expected until at least Sunday, but we are hopeful bore water will not be needed again this summer so long as people remain careful.”

The fact that water consumption was lower than normal last Saturday when rain was predicted the following day and people were at home to use water, shows people understand that the water situation is serious, she said.

Press Release – Kapiti Coast District Council – March 15
As the big dry continues to bite, the Kapiti Council has started using a small amount of treated bore water to supplement the main supply to properties in Waikanae, Paraparaumu and Raumati. It is the first time bore water has been used since December 2010.

Council staff at the Water Treatment Plant behind Waikanae opened the valve to the bore water system just after 8am today. At this point they are using around 20 litres a second to supplement the main water supply which comes from the Waikanae River.

The water is coming from Bore KB4 which is near the Waikanae Park.

“I doubt whether anyone will notice any difference in the treated water they drink at home,” said David Bassett, Council’s Water and Waste Water Treatment Plants manager. “The dilution rate at 20 litres a second is around 10% which is a very small percentage.”

Mr Bassett emphasised that the bore water went through the same treatment phases as water from the Waikanae River plus two extra steps.

“The two extra steps are at the start of the process where we treat for iron and manganese which appear in higher concentrations in bore water. The bore water is then blended with the river water for further treatment before entering the reticulation system.”

Mr Bassett was confident there would be no problem with calcium build-ups (scaling) of electrical appliances as only a very small amount of bore water was being used.

Council’s trigger for using bore water is when the Waikanae River falls below 1100 litres a second. It is currently running below that figure.

“There is always a balancing act between the river flow and consumption. At present residents are being especially helpful by holding consumption down in line with current water use restrictions. The less water they use, the less blending we have to do.”

It was clear recent publicity about water restrictions was having an impact. “Earlier this week consumption in Waikanae was 6.7 million litres, Paraparaumu 10.5 million litres, Ōtaki 4.2 million litres and Paekākāriki 0.86 million litres.

“Following significant publicity, the figures dropped to 6.5 million litres in Waikanae, 10 million litres in Paraparaumu, 4 million in Ōtaki and 0.78 million in Paekākāriki. Clearly people are heeding the warnings and helping out by cutting back on their water use.”

Mr Bassett said the use of bore water would stop as soon as significant rain fell in the headwaters of the Waikanae River.