Streams not as clean as they may seem: study

Bullock Creek flows close to its source near Stone St, in Wanaka. Fish and Game Otago is working...
Bullock Creek. PHOTO: TIM MILLER
High levels of E. coli, excess sediment and water quality issues are just some of the findings from a survey into three Wanaka waterways.

The Upper Clutha Lakes Trust and the Otago Fish & Game Council commissioned Wildlands Consultants to assess the effects of stormwater runoff from urban development in the town.

The survey focused on sediment quantity and quality and its effect on plant and animal life in Bullock Creek, Stoney Creek and Water Race Drain.

Ecologist Melanie Vermeulen sampled 20 sites across the three waterways over four days in September last year.

One interesting finding was that different sites along Bullock Creek had better water quality levels than others, Ms Vermeulen said.

"Everyone is proud of Bullock Creek because it is a community stream and aesthetically pleasing and so I think people assumed the water quality was very good.

"The Touchstone citizen science project had sampled water at the top of Bullock Creek and also at the bottom but the study that I did looked at several sites in between and it really showed how variable the sites are along the whole length of Bullock Creek."

Sediment had the biggest impact on fish life in the stream.

She had found sediment "still hanging around" where there had been breaches in the past from the nearby Meadowstone subdivision into Bullock Creek.

In her report, Ms Vermeulen recommended "it will be important to focus on improvement of sediment management during future subdivision developments".

The report was presented to stakeholders in Wanaka on Tuesday.

Results from the investigation may be used by the community to create a water management plan which included priorities for action to be implemented by the Queenstown Lakes District Council and the Otago Regional Council for future management of the catchment, she said.

kerrie.waterworth@odt.co.nz

 

Comments

Sediment streams into Lake Wanaka from the Beacon Pt Road approach running down the road, and across and downthe beach into the water. This has been made worse by the QLDC requiring drainage from a property to go to a collection spot partway down this beach roadway. It regularly, overflows and has increased the sediment problem since the QLDC required this structure before much more sediment stayed on land.

E.coli are proven in all four southland catchments are by far the majority are from ducks not farmers. Thats a fact and if you dont believe it ask environment southland

The ducks mainly live on farms so must be the farmers fault?

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