Heavy rain is likely to be responsible for flushing additional amounts of an unidentified foamy substance into the Waikato River at Hamilton this morning, says Waikato Regional Council.
Staff have received further reports of a foamy discharge from a stormwater pipe situated at the northern end of the St Andrews golf course today.
The foam has been seen starting to disperse downstream in nearby Pukete.
Further samples of the substance have been collected by regional council staff today for testing, and inquiries are being carried out in the area.
In the meantime, Hamilton City Council staff are carrying out checks of their stormwater network to see if they can identify a possible source for the discharge.
Any members of the public who believe they might know the source of the discharge are urged to contact Waikato Regional Council on 0800 800 401.
The foamy discharge was first noticed about 11am yesterday (Sunday 28 April) and reported to the regional council by concerned members of the public.
While it had been hoped some initial results of samples collected yesterday might be available this afternoon, the council has now been told it might take several days to determine what the substance is.
Because the detergent-like substance remains unidentified, it is not known what – if any – environmental impact it may have.
For that reason, people drawing water from the river immediately downstream of the site are urged to exercise caution and, if concerned, to use alternative water sources until test results are available.