Otago’s longterm freshwater ratings trend low

MOST of Otago’s freshwater sites have a longterm rating of poor or fair for swimming suitability, a new report shows.

Otago regional councillors received a summary of test results for human health risks, relating to faecal contamination and potentially toxic cyanobacteria, in Otago’s rivers, lakes and coastal waters this week.

The results, presented during a data and information committee meeting, were from 27 freshwater and coastal sites, taken between December 2020 and March this year.

Council staff said that across both coastal and freshwater sites, 458 samples were taken.

The ‘‘unsuitable for swimming’’ category was met on 13 occasions due to faecal contamination risk and the ‘‘caution advised’’ category was met on 10 occasions.

For cyanobacteria, no river sites had a riverbed algae bloom; however, two lake sites had a floating algae bloom that reached an amber alert mode.

Most of Otago’s freshwater sites had a poor or fair longterm grade, and only Lake Hawea had an ‘‘excellent’’ longterm grade, the report said.

The freshwater sites that received a poor rating were: Lake Hayes; Taieri River at Outram and Waipiata; and Manuherikia River.

Coastal site results looked better, with nine of the 15 coastal sites monitored receiving a good or excellent rating.

Otokia Creek and Kakanui Estuary were poor.

Committee chairwoman Alexa Forbes said it was a ‘‘sobering read’’.

While some councillors began comparing the results to previous years’ results, strategy, policy and science general manager Gwyneth Elsum said they were not comparable.

The report was an ‘‘advisory service’’ for people to know where was safe to go swimming, not for looking at trends.

The level of bacteria was often dependent on rainfall, so results would be worse following a rain event, she said.

However, Cr Gary Kelliher said he felt it was a ‘‘very positive’’ report, considering it had been a dry season, but with a ‘‘huge’’ rainfall at the beginning of the year.

Chief executive Sarah Gardner said the results did not quite ‘‘stack up’’ when comparing them to the ‘‘aspirational’’ targets that the council set for itself.

Following the meeting, Cr Kelliher said he was disappointed that council staff were unwilling to acknowledge his view.

‘‘My disappointment is that there are landowners making expensive and transformational changes on their properties and at some point the regional council needs to acknowledge these good works, and encourage it to continue.’’

Not acknowledging where results looked better from previous seasons gave the impression that nothing would satisfy the regional council, he said.