Ohinemuri River in Karangahake Gorge turns orange

The Ohinemuri River north of Tauranga has turned bright orange.

Hauraki District Council said it was aware of the issue turning the water in the river orange.

“This is likely from water coming out of old mine workings,” it said in a post on Facebook.

“Waikato Regional Council is investigating the issue and advise for safety reasons, please do not enter the water.

“Our Paeroa water supply intake is upstream of this so is not affected however we’ll be monitoring the situation carefully.”

A regional council spokesperson said it was “urging people to treat bright orange discolouration of the Ohinemuri River as contaminated”.

Senior incident response officer Robert Isaac said the worst-case scenario was the discoloured water being due to a mine shaft collapse, as old mines contained many heavy metals and contaminants.

The Ohinemuri River has turned orange. Photo / Hauraki District Council

The incident was reported to the council about 3pm.

Council staff were at the river assessing the discoloration.

Isaac said staff had yet to identify the source of the discoloration, which appeared to enter the Ohinemuri River downstream of the Waitawheta River.

“Until we can ID the source we need to treat this as worst-case scenario as we are getting reports of people standing in the water.

“If this is an old mine shaft that has blown out then people should not be using or touching the water.”

The worst-case scenario is the discoloured water being due to a mine shaft collapse, Waikato Regional Council says. Photo / Waikato Regional Council

“Other scenarios could include a collapsed out forestry dam or other erosion.”

Isaac urged people to follow the regional council’s Facebook page for updates.

- SunLive