ORC successfully ran three separate water-based programmes over summer, covering water quality monitoring across lakes and rivers, freshwater pest education and engagement and a boatie watercraft safety campaign around coastal and Central Otago.

The separate summer programmes all registered positive levels of public engagement and understanding around the educational aspects of water health, personal boat safety and aquatic pest controls.

Summer recreational water quality monitoring programme

ORC’s Water Quality Scientist, Helen Trotter, says the summer recreational water quality monitoring programme, which ran from December to March, incorporated weekly testing.

This was carried out at more than 30 river, lake and coastal sites across Otago to assess potential health risks from bacteria and toxic algae in waterways.

“Water quality was generally suitable for swimming across Otago during summer- even if the weather was less than ideal at times,” Ms Trotter says.

In total the programme collected and analysed more 450 water samples from over 30 sites.

She says high bacteria counts at levels unsuitable for swimming were detected at 10 sites during the summer, representing about 3 % of all samples collected.

“For most sites this meant a single occurrence which was typically associated with rainfall in the surrounding catchment, immediately prior to the sampling,” she says

Toxic algae blooms were identified at three monitored sites; Butchers Dam near Alexandra, Lake Waihola south of Dunedin and Tomahawk Lagoon, on Dunedin’s coastal outskirts.

Ms Trotter says while no blooms were observed at the monitored river swim sites, toxic algae was confirmed at several other rivers sites across the region and were then listed on the ORC toxic algae notifications webpage.

“In several cases, toxic algae observations were initially reported by members of the community which is a good sign people are engaging with the resources available on LAWA, via the ORC website.”

“We encourage people to take an active interest in how to keep themselves, their pets and others in their communities safe,” Ms Trotter says.

During the off-season LAWA will display the long-term grade for monitored swim sites which indicates the generally suitability of a site for swimming and other water-contact recreation.

Ms Trotter says there is an explanation of the grading system and the monitoring history for each site, which can be viewed under the Why this status? tab on LAWA’s web site.

ORC’s recreational water quality programme will recommence in December 2025.

Water quality and conditions can change quickly at any time of the year. For advice on whether it’s recommended to swim, go to the swim smart checklist on lawa.org.nz.

Summer survey of awareness of ORC’s annual Check, Clean Dry (CCD) campaign

During last summer two Central Otago-based ORC ambassadors surveyed 320 recreational water users, from a total 830 interactions with members of the public.

ORC’s Manager Environmental Implementation Libby Caldwell says while there had been some “solid” areas of awareness around the Check, Clean, Dry (CCD) campaign, to keep watercraft free of pests, there remained room for improvement – between those who were ‘aware’ (238 people/ 74 %) of CCD and those ‘unaware’ (82 people/ 26 %).

“Checking, cleaning and drying watercraft to prevent the transfer of unwanted pests to new locations should be priority for watercraft users and swimmers. Some pests, both plant and animal, have the capacity to become easily established and cause devastation to waterways,” Mrs Caldwell says.

“Of the 320 people surveyed, 238 (74%) were ‘aware’ of CCD but the remaining 82 (26%) were in the ‘unaware’ category,” she says.

It was good that 36.6% of people aware of CCD ‘almost always’ did a Check, Clean (38.7%) and Dry (64,3%), she says.

However, Mrs Caldwell noted that of those ‘unaware’ of CCD, 56.1 % almost never did Check, 47.6% almost never did clean and 17.1% almost never did Dry.

“There’s still a sizeable gap in the adoption of accepted practice, and a key change would be to see as move by those ‘aware’ of CCD from doing CCD ‘sometimes’ to ‘often’,” Mrs Caldwell says.

Mrs. Caldwell states that while 35.3% of respondents used dishwashing liquid or hot water (6.6%)—both proven methods

for removing pests—24.4% did not clean their watercraft at all or did so insufficiently, and 27.8% relied only on a water rinse.

For drying, the majority (67.5%) correctly allowed their equipment to dry for mor than 24 hours, while 32.5 % dried it for

less than the recommended time in total.

Origins and activities of the 320 respondents

About 73.1% of the 320 respondents were from Otago, 10.3% from Canterbury and 6.5% from Southland and the balance from West Coast (0.3%), North Island (1.9%) and elsewhere (7.8%).

The most common activity of respondents was swimming, 54.9%, boating at 47.9% and fishing at 19.6%. The frequency of doing freshwater activities was 50.9% a “few times a week’ and about 13% each for “daily” and “weekly” frequency.

Swimming - 54.9%

Boating - 47.9%

Fishing – 19.6

Kayaking, at 12.6%

Jet skiing - 10.4%

Other activity – 6.3%

Water Skiing – 0.9%

Scuba diving/Snorkelling 0.3%

Freshwater Pest Awareness

272 of respondents (85.3%) were able to list at least one freshwater pest.

The most common freshwater pest named was Didymo, listed by 95.6% of the 272 respondents, followed by Lagarosiphon, at 47.4%.

Mrs Caldwell highlighted that while it was encouraging people were well aware of Didymo and Lagarosiphon,

they needed to recognise other pest not yet in the region such as the Gold Clam or Hornwort to help check their spread.

“Thorough washing of watercraft and trailers and then drying for more than 24 hours is the best combatant,” she says.

Didymo - 95.6%

Lagarosiphon - 47.4%.

Gold clam – 11%

Lake Snow – 9.6%

Hornwort – 5.5%

Carp – 4.8%

Egeria 3.3%

Hydrilla – 1.8%

Parrots Feather – 1.5%

(Total percentage is more than 100% as respondents could name more than one pest).

ORC Harbourmaster Steve Rushbrook on public engagement

Mr Rushbrook says the Harbourmaster team has had a good year out on the water, with great engagement with the public in Central Otago especially, over the holiday periods.

He says the number of incident reports have not been high and generally people appear to be more conscious of being safe on the water.

“We’ve found only a very small percentage of people are not wearing their lifejackets and have to be reminded.”

Mr Rushbrook highlighted the team is still seeing quite a few vessels without identification on them.

He is urging people to read the navigational bylaws around what is required; to display an identifying name or number on their vessel.

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