River water use restricted in parched parts of Northland

Some Northland farmers are having to restrict the amount of water being taken from local rivers as the region continues to dry out.

New figures show parts of Northland experienced some of the driest conditions in decades last year, and authorities are keeping a close eye on the situation, with no significant summer rain forecast.

Northland Regional Council's group manager regulatory services Colin Dall said a number of Northland rivers were now below designated 'minimum flow' levels designed to limit the amount of water that can be taken during dry periods to protect river ecology.

"Things are changing as staff carry out manual gauging to confirm low flows in different catchments, but at this point, we've got about half a dozen consent holders who have ceased their takes in accordance with their resource consent conditions (mainly in the Mid and Far North areas) and council has also had to impose restrictions on some other users," said Dall.

He said district councils taking water for public supply and farmers irrigating pasture were among the biggest users among the several hundred people or organisations with resource consent to take water, including some major users consented to take hundreds of thousands of litres daily.

However, there were also hundreds of other Northland users taking relatively small amounts of water who don't need resource consent.

Northland Regional Council Hydrology Monitoring Officer Marcus Schlesier gauging flow rates in the Kerikeri area.
Northland Regional Council Hydrology Monitoring Officer Marcus Schlesier gauging flow rates in the Kerikeri area. Photo credit: Supplied

The council had been advising people for some time not to wastewater and to make sure they had taken sensible precautions for the dry conditions, especially those relying on their own supply/with water tanks.  

"The council has also contacted some of its more vulnerable water take consent holders/water users urging them to conserve water where possible."

With summer now in full swing - and no significant rain forecast - members of the council's hydrology team were currently gauging some of the more critical rivers in the region to ensure they had the most up-to-date data and figures to work with.

"Preliminary information suggests a number of rivers are already below 'minimum flow' levels, and although this isn't unusual over a dry summer, this wouldn't usually happen until February or March and is linked to last year's drier conditions."

Meanwhile, rainfall figures for 2019 had confirmed it had been one of the driest on record in many parts of Northland, and in one case, the second driest where those records stretched back more than a century.

 "Just 1100mm of rain was recorded in the Puhipuhi area north of Whangarei last year, a little over half the average 2000mm annual rainfall and making it the second driest year there since 1914."

 The Kaitaia area had recorded the driest year since records began in 1949 (791mm compared to an average 1350mm) and Kerikeri's 1165mm was the third driest since records began in 1945 and again, significantly under its 1490mm yearly average.

 Whangarei too had had a very dry year, the 837mm recorded at its airport the driest since records began in 1943 (and compared to a yearly average of 1364mm).

 Ngunguru had received 967mm (yearly average 1790mm) and the Brynderwyn area south of Whangarei 976mm (yearly average 1390mm), the lowest rainfall in both areas since records began in the 1980s.

 Dall said with such a large rainfall deficit, it could take the region overall a number of years to recover, even once summer was over and the rain came again.