‘Unusual’ early water demand spike in Gisborne as warm season approaches

Pictured: The Waingake water treatment plant. With a dry summer predicted by Niwa, Gisborne District Council is urging conservative water use. Photo / Ben Cowper

A surprise early demand spike for water struck Gisborne ahead of a summer which is expected to be warmer than usual for the region.

Residents of Gisborne were told to be sparing with their water usage this month as the council urgently fixed part of the city’s water pipeline.

The water supply was unexpectedly put under more pressure as the warmer weather had caused the city residents to double their water usage, from 500 cubic metres per hour to 1000cu m per hour.

The council said this level of usage was unusual so early in spring, and with a dry summer predicted, they urged residents to be conservative with water.

Despite the rain scattered throughout this week, National Institute of Water and Atmospheric Research (Niwa) principal forecasting and media scientist Chris Brandolino says signals show Gisborne could experience warmer days than normal during November and December.

“The second half of November could be very warm, with a 55% chance of temperatures [being] above average,” Brandolino said.

He said the Niwa outlook for October through to December shows chilly temperatures will be a theme in Tairāwhiti this week, with some rain to be expected.

By this Friday, the weather will have an upward turn to warmer temperatures, which will be the theme for much of the rest of the year.

“The rest of October will have a warmer-than-usual theme.”

However, he said water tanks will be thankful for the end of October and the start of November, as wetter-than-usual weather is to be expected all over the North Island, including in Tairāwhiti.

“So that would be potentially some good news from a water perspective.”

After the first week in November, the weather signals will be trending toward a period of settled and potentially unusually warm weather for what’s considered average for November, which may persist into December and possibly even the new year.

“Doesn’t mean every day will be dry and warm, but that’s just kind of the [weather] theme.”

Early indications also show from mid-January into mid-March, there may be a lean toward unsettled weather and wet weather, “with maybe increased odds for rain”.

Clearer indications of summer weather patterns will be released by Niwa towards the end of November, he said.

When the council carried out pipe repairs from the Mangapoike dams to the Waingake treatment plant earlier in the month, it temporarily affected the city’s treated water volumes.

High water usage meant the council had to dip into an alternative water supply from the Waipaoa Treatment Plant.

Council drinking water manager Judith Robertson says the damage to the pipe joint was caused by land movement, with the river undermining a section of the pipe.

Robertson said it’s common for water usage demands to increase into November and December and decrease over the Christmas break.

She said there is also high demand in January and February, especially when there are multiple days of sunny weather.

“The level of demand experienced [last week] was unusual so early in spring.”

As predictions show this summer could be a dry one, Robertson shared some tips and tricks for water conservation:

• Consider installing rainwater collection tanks for garden watering.
• Limit sprinkler usage – direct watering or dripper irrigation can provide effective garden watering.
• Manage swimming pool water treatment to avoid needing to empty and refill pools - this includes the smaller-framed pools often put up and filled multiple times over the summer. Use a cover on the pool to minimise evaporation.
• Fix leaking taps and running water cisterns.