Tough summer for water supply looks likely

Greater Wellington and the region's four city councils are calling on residents to go easy on garden watering, as the warm, dry weather makes a tough summer for water supply look increasingly likely.

The cities’ two main water supply rivers are lower than is usual for this time of year and on Sunday 2 December the system supplied 194 million litres of water to the cities, exceeding last summer's maximum supply for one day.

"Even though we’ve had a bit of rain over the weekend, our rivers aren't as full as usual and demand has hit a level we don't usually see until well into January," said Greater Wellington's Parks, Forests and Utilities Committee Chairman, Rex Kirton. "Taken together with recent forecasts of a long, dry summer, we may find it tough to meet all demand for water later in the summer."

Outdoor water use, particularly garden watering, is the main reason for surging demand. A garden hose left running for an hour can account for 1,000 litres of water. That’s as much as a family would use on a winter day.

As river levels drop, Greater Wellington relies increasingly on storage lakes at Te Marua (which hold three weeks' average water supply) and the Hutt aquifer to meet demands from Wellington, Hutt city, Porirua and Upper Hutt.

"We're watching water use and our storage pretty closely. We'll be working with local authorities on extra watering restrictions if our water reserves start to run down," said Cr Kirton.

For now, Greater Wellington and the region's city councils are asking people to take extra care with their water use in the coming weeks, to help avoid the need for tougher restrictions.

"We'd like all gardeners to mulch exposed soil beds (to slow water evaporation), check their soil needs moisture before watering, target watering at the root zone of plants and time sprinkler sessions to 30 minutes. These few simple steps can make a real difference," Cr Kirton said.

Routine watering restrictions are now in effect in Wellington, Hutt city, Porirua and Upper Hutt with unattended watering (such as sprinklers) limited to a two-hour period in the morning or early evening. For each city's watering restriction details and more water conservation tips, see www.bethedifference.gw.govt.nz