No quick fix for Waikato River as second report card shows 'deteriorating' trend

The Waikato River Authority has funded many projects around Lake Karāpiro in the past decade, including removal of car bodies and waste as well as riparian planting.
Christel Yardley/Stuff
The Waikato River Authority has funded many projects around Lake Karāpiro in the past decade, including removal of car bodies and waste as well as riparian planting.

The health of the Waikato River continues to decline despite millions of dollars and hundreds of hours put into restoring the country’s longest awa over the past decade.

The Waikato River Report Card for 2010-2019, released on Wednesday, showed overall there was more deterioration than improvement when it came the river’s water quality and ecology.

Problem areas in water quality included E coli, total nitrogen and dissolved oxygen, all scoring more points in the “deteriorating” column.

There were also more deteriorating trends in the ecology of the river when it came to tracking insects, aquatic plants, algae and riparian health.

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Waikato River Authority Crown co-chair Paula Southgate said the authority planned to ramp up its efforts to fix the wellbeing of the river over the next 10 years.
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Waikato River Authority Crown co-chair Paula Southgate said the authority planned to ramp up its efforts to fix the wellbeing of the river over the next 10 years.

But there were also some signs of improvement around water clarity, water temperature, arsenic and chlorophyll a​, a measure of the amount of algae growing in the water.

The report card formed the core of the Waikato River Authority’s five-year report for the Crown and the river iwi of the Waikato River.

The report was prepared by Niwa and data collected from five zones was used: Huka-Ōhakuri near Lake Taupō; Ōhakuri-Karāpiro; Waipā; Mid-Waikato and Lower Waikato where the river enters the Tasman Sea.

A total of 65 sites were used to measure water quality and 27 for water ecology.

The water quality trends showed total phosphorus, which included all types of the chemical, was still a major problem mainly for smaller streams feeding into the Waikato River.

Dissolved oxygen, which is the oxygen in the water that freshwater fish filter to breathe, was also at the extreme end of the “deteriorating” scale in the report.

Niwa freshwater scientists Neale Hudson and Elizabeth Graham worked on the report and said it would take time for the river to respond to the mitigation work the river authority had undertaken.

“Take nitrogen, that’s in the landscape because of its historical activity and it’s slowly working its way to the river,” Hudson said.

The Waikato River Authority, back row: Danny Loughlin, Roger Pikia, Paula Southgate, Dylan Tahau, Wikitōria Tāane. Front: Tipa Mahuta, Erina Watene-Rawiri, Jackie Colliar, Nachelle Griffiths and Stu Kneebone.
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The Waikato River Authority, back row: Danny Loughlin, Roger Pikia, Paula Southgate, Dylan Tahau, Wikitōria Tāane. Front: Tipa Mahuta, Erina Watene-Rawiri, Jackie Colliar, Nachelle Griffiths and Stu Kneebone.

“The mitigation work is intended to reduce the amount getting into the river at some point.”

There was some lag time and so it was “going to get worse before it gets better”.

“That just depends on the dynamics of how the material is transported to the river, whether that’s via groundwater or surface flow.”

The river authority funded $30 million for almost 200 projects aimed at restoring the health of the river.

Its iwi co-chair and Crown co-chair Tipa Mahuta and Paula Southgate said an 80-year timeframe was needed to see significant improvement.

Southgate said there was no “quick fix” to restore the river.

“The reality is the river isn’t as healthy as we all want it to be but the goal of being able to swim and take food from the river is something we are committed to.

“The key is to learn from the good work of the past 10 years and really push harder over the next 10.”

Southgate said the authority is reviewing its strategy for the river and it would likely put a focus on elevating restoration work above what’s already been achieved since 2010.

Five year report

  • 2,168,104 native trees and shrubs planted.
  • 64,279 non-native trees planted, such as poplar for erosion control.
  • 393km of waterway fencing completed.
  • 406 community engagement events held.
  • 10,163 people attended those events.
  • 1756ha of riparian land restored.
  • 386ha in production forestry/mānuka.
  • $30m distributed to nearly 200 projects.