KEY POINTS:
Geothermal activity, rather than pollution, may be behind the blackening of one of Rotorua's streams.
Environment Bay of Plenty has been investigating the health of a section of the Puarenga Stream after a member of the public raised concerns about the blackened colour of the water along the Sulphur Flats walking track.
The walking track starts at Amohau St, just past Hinemaru St, and makes its way along the Puarenga Stream, eventually finishing back on Amohau St, at the intersection of Sala St and Te Ngae Rd.
Compliance officer Steve Pickles said the regional council received a complaint this month about the stream being black.
He said scientists were not 100 per cent sure about the cause of the water's colour as final tests were still a couple of weeks away.
However, he said, initial findings showed the area's geothermal activity was behind the blackened water.
Mr Pickles said the blackened water was caused by a lack of oxygen, which could be caused by the geothermal activity.
"I think it's typical of that area," Mr Pickles said.
It was possible the darker water could come and go.
"I suppose after a period of rainfall it'll flush out a bit [of dark water]."
- NZPA
