Wellington 's drought - Yesterday's extreme has become today's norm

In the weekend I was interviewed for the local Hutt Valley newspapers by journalist, Jim Chipp. This is the article as it appeared in the Hutt News.

Apart from the odd small factual error (understandable taking an interview in shorthand on a pad on the river bank) the situation has been represented well.

Here’s hoping some people will notice and start joining some dots

Local dry spell or global drought?

By Jim Chipp

Hutt News,

3 March, 2014

The region's January rainfall was the lowest since records began in 1879. but is it a passing dry season or the start of something worse?

It could well be the latter, according to Alicetown river observer Robin Westenra.

Karori Reservoir recorded 3.8 millimetres of rain during the month, the lowest since 1879, compared to the long-term average of 81 mm

Wainuiomata Reservoir got even less, with 1.8 mm, the least since 1890, according to Greater Wellington regional council.

The Hutt River flow rate at Kaitoke on February 1 was 1215 litres per second, down 35% on January's average, which was 65% below the long-term average for January.

If the level drops below 600 litres per second, Greater Wellington's resource consent requires it to stop taking water at Te Marua.

Westenra has been taking an interest in the Hutt River’s changes for years and says the long-term trend is grim.

“It seems to me that we've had three really dry seasons in a row," he said.

"I don't see this finishing any time soon.”

It is far from a local dry spell, he said. Most of the world was experiencing drought conditions, other than Eastern Europe.

California was facing a 1000-year drought and declared a state of water emergency in January.

The water supply for Brazil's largest city, Sao Paulo, was critical in the middle of the rainy season.

Westenra said the situation is the same across most of the world, as a result of global warming.

With the Arctic ice melting, the jet stream has changed its pattern bringing cold, Arctic air south into North America and Europe.

At the same time warm air from the south has entered the Arctic through the Bering and Fram Straits, warming the northern hemisphere and bringing drought.

“The worry In my mind is not so focused on sea level rise. It's the desertification of the land and habitat so we won't be able to grow our food," Westenra said.

“To assume that New Zealand's drought, and Wellington's water crisis is just a one-off local situation appears, in my mind, to be pure wishful thinking.”

Greater Wellington is responsible for supplying the region with water and its staff have taken a low- key approach, calling for restraint with garden watering.

It has been an "exceptionally dry start to the 2015 year" which had added to the already dry conditions prevalent since October.

Sprinkler restrictions are in place.

Wellington Water operations manager Noel Roberts said the Te Marua storage lakes were there to underpin supply in times like this, but there was quite a bit of summer still to come.

“We’re okay right now, but can't know how dry it's going to be, or for how long, so extra care from the community now will leave us better placed to cope with worsening dry conditions, should that arise.”

This indicates declines in the flow rates in the Hutt River at midstream

For an update of conditions

Here is the general situation in New Zealand as a whole, in terms of soil moisture deficit, one of the indicators of drought, commpared with the historical average and with last year (also much drier than usual)

Here is how things look in terms of the south Pacific. During February (which seemed cooler than usual) NZ sat in cololer-than-average waters. At present NZ is in waters that are 2-3C warmer than the historic average