9 Aug 2024

Canterbury river and lake levels drop as dry winter persists

7:01 am on 9 August 2024
Aerial shots of Lake Camp, inland from Ashburton, taken on August 2 showing the water level in the high country lake

Aerial shots of Lake Camp, inland from Ashburton, taken on August 2 showing the water level in the high country lake. Photo: Owen Payne / Environment Canterbury

Dry winter conditions are causing rivers and lakes across the motu drop to low levels - affecting the ecology of the waterways as well as pushing up power prices.

The Canterbury Regional Council says a lack of rain and snow melt continues to put significant pressure on lakes and rivers across the region, including at the popular Lake Camp/Ōtautari.

Vanessa Wright has been visiting the Ashburton Lakes (which includes Lakes Camp and Clearwater) in the Hakatere Conservation Park, since she was a child.

"My mum and dad took me there when I was a kid and my dad, a builder, built a bach out of leftovers from every job that he had and I grew up swimming in Lake Camp and jumping off the raft with my sisters."

Vanessa Wright’s kids swimming in Lake Camp in October 2021, when the water level was much higher.

Vanessa Wright's kids swimming in Lake Camp in October 2021, when the water level was much higher. Photo: Vanessa Wright/Supplied

She said the beautiful Lake Camp, nestled in the Canterbury high country was known to have fluctuating levels - but it was currently lower than she had ever seen it.

"It's definitely the lowest point since Environment Canterbury started their recording, there is no swimming area anymore, we are seeing dead kākahi (freshwater mussels) on the beach, I got a photo on Saturday of hundreds of them dying."

A member of the Lake Clearwater Hutholders Association, she said the group want to see a diversion from the nearby Balmacaan Stream reinstated, in a bid to protect the lake's health.

Fish & Game held a consent to divert water from the stream into Lake Camp, but relinquished it in 2020, after it had been in place for more than 50 years. The diversion structure was then wiped out in a flood the following year.

A map showing a number of the lakes in the Hakatere Conservation Park, in mid Canterbury.

A map showing a number of the lakes in the Hakatere Conservation Park, in mid Canterbury. Photo: Environment Canterbury

Wright said without the diversion, many were concerned about the falling lake levels and the impact it would have on water quality, native wildlife and the ability to use the lake for recreational purposes.

"I'm not an expert in this area but if we are spending millions of dollars trying to turn other lakes around then surely it is more sensible and cheaper to actually put the diversion back in place while it is still in an OK state before we have to spend millions of dollars to try and turn it around."

But the Canterbury Regional Council maintained Lake Camp was in good condition, despite being at a low level.

Lake Camp in the Hakatere Conservation Park at higher levels in January 2022.

Lake Camp in the Hakatere Conservation Park at higher levels in January 2022. Photo: Samantha Gee/RNZ

Council monitoring water quality

Council's water science manager Dr Elaine Moriarty said lack of rain this year was having a widespread impact on the region's waterways with some rivers - like the Hurunui - so low they could be crossed on foot.

"We really are seeing some of the driest conditions we have seen since the 1980s, some are the driest they have ever been so it's quite unprecedented for us to be heading into summer with our rivers and lakes at such a low level."

She said the council was not seeing a negative impact on Lake Camp's water quality as a result of the low water levels but it would continue to be closely monitored for negative impacts over the coming months.

The lake had a depth of up to 18 metres at the centre, which Moriarty said made it more tolerant of fluctuations that shallower lakes and helped it to support aquatic life during dry times.

She said the regional council could not hold a consent to divert water as they were the regulator, but council staff were happy to discuss resource consent applications with interested parties - though there was currently very limited water available for diversion and no structure in the stream to enable it.

Rising power prices

Meanwhile, Transpower acting chief executive John Clarke said the country's hydro lake storage was at about 57 percent of what it would normally be at this time of year.

"We have done some modelling that looks at what if that continues and at this stage that might lead to things like having to ask consumers to conserve electricity in a few months time, but certainly there is no immediate need for concern.

But in the meantime - it's having an impact on wholesale power prices - which have doubled in the past three weeks.

Amid the rising costs, associate energy minister Shane Jones said the Government was exploring the option of intervening into the electricity market to force major energy generators to cut prices to major users.

Clarke said it was working with the Electricity Authority on what actions could be taken in coming weeks if hydro lake levels continue to recede.

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