Friday, 14 October 2022 16:55

Water quality results reinforce need for action

Written by  Staff Reporters
Lake Heron. Photo Credit: Environment Canterbury Lake Heron. Photo Credit: Environment Canterbury

Hundreds of water samples taken from Ōtūwharekai Ashburton Lakes and streams over the past year confirm that water quality remains a concern, according to Environment Canterbury.

The water monitoring results were presented to the Ashburton Water Zone Committee by Environment Canterbury and the Department of Conservation (DOC), who are part of the Ōtūwharekai Working Group to restore lake health and cultural values.

The findings from the results show negative and some positive changes across the different lakes and streams of the catchment, says Dr Tim Davie, director of science at Environment Canterbury.

“These are small to medium-sized lakes and streams in the high country, which means results often fluctuate from year-to-year due to climate conditions and other variables.”

Davie says, however, that the results seem to show increasing nutrients and algae, which are causing worsening water quality over the past ten years.

“Work is already underway to reduce nutrients entering the waterways from farming activity, and the nearby long-drop toilets in the huts settlement have been decommissioned. However, these actions could take some time to make a difference to water quality results,” he adds.

According to Davie, there is some good news.

“The positive news is there had been a real willingness by landowners and local farmers to continue to go beyond their regulatory requirements to address issues in the catchment, so we’re confident change is possible.”

All of the lakes in Ōtūwharekai are above their Tropic Level Index (TLI) limit, meaning they do not meet the outcomes for freshwater health expected by the community. The TLI measures overall lake health by assessing nitrogen and phosphorus (nutrients) and algal biomass (algae).

The amount of algae in the lakes was generally high for these types of lakes but there were some individual differences from lake-to-lake.

“It was pleasing to see Te-Puna-a-Taka/Lake Clearwater decrease in algae biomass this summer but it’s too early to say if this is pause in decline or reversal of the degrading trend,” says Davie.

“On the other hand, Ōtūroto/Lake Heron, is showing a continued increase in algae, and high numbers of the nuisance algae Ceratium, which is very good at outcompeting other algae for nutrients.”

Department of Conservation technical advisor – freshwater Dr Tom Drinan says nitrogen concentrations in streams have increased significantly in the Ōtūwharekai catchment in the last ten years.

“Most sample sites have seen a two to three-fold increase in nitrogen concentrations, with current concentrations being very high for these high-country streams,” he says.

“For comparison, nitrogen concentrations at our reference site at Paddle Hill have remained consistently low during the same ten-year period. These worsening nitrogen concentrations continue to pose a risk to the ecological health of these streams and the lakes and rivers they flow into.

“Encouragingly, there has been some reduction in phosphorus concentrations over the same period at these sites.”

The Ōtūwharekai Working Group was established in 2019 to instigate collaborative and urgent action to halt and reverse the degradation of Ōtūwharekai ecology and values.

The Group is made up of Papatipu Rūnanga with connection to the area – Te Rūnanga o Arowhenua, Te Ngāi Tūāhuriri Rūnanga and Te Taumutu Rūnanga – as well as Te Rūnanga o Ngai Tahu, Environment Canterbury, farmers in the area, Department of Conservation, Toitū Te Whenua LINZ, Ashburton District Council, Central South Island Fish & Game, the Ministry for the Environment and Ministry for Primary Industries.

More like this

Rare species discovered at stream restoration site

Rare Canterbury mudfish and tadpole shrimp have been discovered at an environmental restoration site at Bennetts Stream in North Canterbury which is part of a biodiversity initiative being carried out by Waimakariri Irrigation Limited (WIL).

Speedy chair

OPINION: Federated Farmers and its members don’t have much love for regulations-obsessed regional councils.

Say nothing!

OPINION: Normally farmer good organisations are happy to use the media to get their message across to politicians and the consumers.

New board resurrects show

The new chair of the Canterbury A&P Association (CAPA) board, Sir David Carter, is pleading for public support for this year's Christchurch Show.

Featured

Boost for hort exports

The horticulture sector is a big winner from recent free trade deals sealed with the Gulf states, says Associate Agriculture Minister Nicola Grigg.

Better animal genetic gain system

A governance group has been formed, following extensive sector consultation, to implement the recommendations from the Industry Working Group's (IWG) final report and is said to be forming a 'road map' for improving New Zealand's animal genetic gain system.

SIDE 2025's new schedule, venue

Annual farmer gathering, the South Island Dairy Event (SIDE), is set to make history as it heads to Timaru for the first time.

Taranaki piggery goes solar

Installing 400 solar panels at their Taranaki piggery and cropping operation will have significant environmental, financial and animal welfare benefits for the Stanley family.

National

The show is on!

It was bringing in a new Canterbury A&P Association (CAPA) show board, more in tune with the CAPA general committee,…

Food charity to hold online auction

Meat the Need, New Zealand’s dedicated charity delivering locally sourced protein meals to food-insecure communities, is launching an online National…

Machinery & Products

An ideal solution for larger farms

Designed specifically for large farms that want to drill with maximum flexibility, efficiency and power, the new Lemken Solitair ST…

Landpower increases its offering

Landpower and the Claas Harvest Centre network will launch the Claas Scorpion and Torion material handling solutions to the market…

» Latest Print Issues Online

The Hound

Leaky waka

OPINION: Was the ASB Economic Weekly throwing shade on Reserve Bank governor Adrian Orr when reporting on his speech in…

Know-it-alls

OPINION: A reader recently had a shot at the various armchair critics that she judged to be more than a…

» Connect with Rural News

» eNewsletter

Subscribe to our weekly newsletter