Local Govt | National News Video | Parliament Headlines | Politics Headlines | Search

 

Hot weather in ChCh sees less water in rivers

Hot weather and easterlies: less water in rivers, groundwater levels drop

The sustained hot, dry weather in Canterbury for much of January has depleted water sources in the region, say Environment Canterbury water scientists.

Since July 2007, rainfall throughout most of Canterbury has been at a ten-year low, driven by the dominating easterly winds characteristic of the La Niña weather pattern.

“Groundwater levels are much lower than at the same time last year and are continuing their steady decline since last summer,” said Dr Howard Williams, ECan groundwater scientist.

River and stream flows have also been adversely affected by the lack of rainfall as have soil moisture levels which are as low or lower than two summers ago, he said.

“Mid January, 25 of the 34 major catchments within the Canterbury region experienced partial or full irrigation restrictions on some or all of their tributaries,” he said. Groundwater in the West Melton area near Christchurch is also under restriction.

“Substantial rainfall is needed in the next few weeks otherwise many more rivers will be running at flows where irrigation restrictions will be applied on both groundwater and river water abstractions.”

General state of river and stream water The main alpine rivers are flowing at below average levels for this time of year. The Waiau and Waimakariri Rivers are at 60 percent of average for December and the Rakaia and Rangitata Rivers are around 80 percent of their average flows.

Flows in North Canterbury for December were well below average with the Waipara River below 20 percent of expected flows. In South Canterbury flows in rivers are only marginally better, with river flows around 50 percent of the December average.

The Selwyn River at Coes Ford, Irwell River and Harts Creek in Central Canterbury are well below their minimum flow.

General state of groundwater In general, groundwater levels are significantly lower than at the same time last year. Around 85 percent of the region’s moderate to deep monitoring wells (greater than 30 metres deep) are at below average groundwater levels. Similarly, 75 percent of the region’s shallow monitoring wells (less than 30 metres deep) are at below average groundwater levels.

Regional detail North Canterbury Kaikoura and Waipara areas groundwater levels are well below average. In Kaikoura, most monitoring wells are at historic lows for the time of year. In Waipara most wells are setting new historic lows, while the remainder are at average to low levels. In contrast, wells in the Ashley – Waimakariri groundwater zone display generally average levels of groundwater, with only a few wells showing low to historic low levels. These average groundwater levels are in part buoyed up by water discharged to ground associated with the Waimakariri Irrigation Scheme.

Mid-Canterbury Groundwater levels within the Christchurch – West Melton area are generally lower than average for this time of year. In many cases they are lower than the low levels encountered in early 2006 (a previous dry period) and for some wells record lows are being recorded. Three of the Christchurch-West Melton monitoring wells indicate groundwater levels below 1st trigger levels, placing part of the area on restriction, whilst groundwater levels in the other two trigger wells are close to the 1st trigger level. Both the Selwyn-Waimakariri and the Rakaia-Selwyn groundwater zones are displaying levels far below those of last year, nearer those recorded from the summer of 2005-6. In the Selwyn-Waimakariri zone many groundwater levels are at very low to historic lows. Similarly, in the Rakaia-Selwyn zone, nearly all groundwater levels are below average levels with most of these at very low to historic low levels. In the Ashburton-Rakaia zone all groundwater measurements are below average levels and most are at very low to historic low levels.

South Canterbury In the Mayfield-Hinds groundwater zone, 73 percent of groundwater levels are below average levels. Shallow groundwater levels between the Rangitata River and Coopers Creek are at low levels with some wells at record lows for this time of year. In the deep aquifer at Orton, groundwater levels are at an all time low. Shallow wells near the Orari River are at below average levels with some wells at or near record lows for this time of year. Shallow wells closer to the Waihi and Te Moana Rivers are at average levels for this time of year. In the Upper Waitaki groundwater levels overall are decreasing, with approximately a quarter of all wells monitored exhibiting their lowest levels since monitoring began a year ago. In the Pareora-Waihao zones, shallow groundwater associated with the Pareora and Otaio Rivers continues to drop to low or very low levels, associated with a lack of river recharge. The Waihao River area fares better, with average water levels. Deeper groundwaters are at low levels for the three years of record.

The most recent monitoring data are available at: http://www.ecan.govt.nz/Our+Environment/Water/Groundwater/Groundwater+Levels

Irrigation restrictions For an updated list of irrigation restrictions go the Environment Canterbury homepage (www.ecan.govt.nz) and click on Irrigation restrictions, bottom right.


ends

© Scoop Media

 
 
 
 
 
Parliament Headlines | Politics Headlines | Regional Headlines

Gordon Campbell: On The Life And Times Of Peter Dunne

In the end, Mr Pragmatic calmly read the signs of impending defeat and went out on his own terms. You could use any number of clichés to describe Peter Dunne’s exit from Parliament.

The unkind might talk of sinking ships, others could be more reminded of a loaded revolver left on the desk by his Cabinet colleagues as they closed the door behind them, now that the polls in Ohariu had confirmed he was no longer of much use to National. More>>

 

Gordon Campbell: On Labour’s Campaign Launch

One of the key motifs of Ardern’s speech was her repeated use of the phrase – “Now, what?” Cleverly, that looks like being Labour’s response to National’s ‘steady as it goes’ warning against not putting the economic ‘gains’ at risk. More>>

ALSO:

Lyndon Hood: Social Welfare, Explained

Speaking as someone who has seen better times and nowadays mostly operates by being really annoying and humiliating to deal with, I have some fellow feeling with the current system, so I’ll take this chance to set a few things straight.. More>>

ALSO:

Deregistered: Independent Board Decision On Family First

The Board considers that Family First has a purpose to promote its own particular views about marriage and the traditional family that cannot be determined to be for the public benefit in a way previously accepted as charitable... More>>

ALSO:

Transport Policies: Nats' New $10.5bn Roads Of National Significance

National is committing to the next generation of Roads of National Significance, National Party Transport Spokesperson Simon Bridges says. More>>

ALSO:

Gordon Campbell: On Why Labour Isn’t Responsible For Barnaby Joyce

As a desperate Turnbull government tries to treat the Barnaby Joyce affair as a Pauline Hanson fever dream – blame it on the foreigners! We’re the victims of the dastardly New Zealand Labour Party! – our own government has chosen to further that narrative, and make itself an accomplice. More>>

ALSO:

Rail: Greens Back Tauranga – Hamilton – Auckland Service

The Green Party today announced that it will trial a passenger rail service between Auckland, Hamilton and Tauranga starting in 2019, when it is in government. More>>

ALSO:

Housing: Voluntary Rental Warrant Of Fitness For Wellington

Wellington City Council is partnering with the University of Otago, Wellington, to launch a voluntary Rental Warrant of Fitness for minimum housing standards in Wellington, Mayor Justin Lester has announced. More>>

ALSO:

 
 
 
 
 
 

LATEST HEADLINES

  • PARLIAMENT
  • POLITICS
  • REGIONAL
 
 

Featured InfoPages

Opening the Election