Otago Regional Council (ORC) have completed their investigation into why hundreds of native fish died in a spring fed creek near the Wānaka showgrounds in early February.
Touchstone Project leader Chris Arbuckle said he was alerted to the dead upland bullies and koaro by two locals, and immediately contacted Otago Regional Council (ORC) to investigate possible pollution.
Manager Compliance, Tami Sargeant, said the most likely source of the fish death was that an ammonia-based product was flushed down the drain.
“The source of ammonia in an urban environment is likely to be household use of cleaning products, septic systems or improper disposal of ammonia products, but we have been unable to identify how the ammonia-based household product entered the drain.
“The mud tanks have been cleared to prevent further pollution occurring, and the creek has been re-inspected and no more dead fish have been seen,” said Sargeant.
The creek is monitored regularly through a Touchstone and ORC water quality project, and a stormwater drain exiting from Landsdown Road has been the source of pollution there before.
“The drain has a history of people dumping whatever in it so it’s one we keep an eye on,” said Arbuckle. “Last year during the Wānaka A&P Show it was full of blue paint, flowing from the same suspect drain.”
“Most stormwater is not treated before it drains into our local waterways, which is why it is important to only drain rain and avoid flushing things into the stormwater network that could be harmful for the environment,” said Sargeant.
Read edition 1016 of the Wānaka Sun here.