Residents around Sullivan Lake are bracing for another stench-filled summer from decaying vegetation and decomposing wildlife.

Although Whakatane District council has set aside a budget to clean the lake, work to remove the Mexican water lily is not due to start until at least June next year.

Brian Corbett has lived beside the lake for more than 20 years and been a member of the Sullivan Lake Care Group since 2013.

“It’s got weed growing all over it. We have people coming to visit and they ask us, ‘whatever has happened to the lake?’ It used to be so attractive for visitors.

“It’s getting worse, and if something isn’t done about it goodness knows what will happen.

He was also sad to see the legacy of the late Sir William Sullivan, who developed the southern end of town and created the lake, falling into decline.

He had heard from another person living by the lake that the council would no longer be spraying the weeds with herbicide as people complained about the smell of the dying vegetation.

As well as the Mexican water lily (Nymphaea mexicana), he said maintenance of other weeds growing around the edge of the lake is unsightly.

He worries about the welfare of birdlife on the lake.

"I occasionally see white herons (kōtuku) and black swans on the lake, but there is nowhere near as many as there used to be."

“The weed is spreading. It’s only going to get worse the longer they leave it.

Invasive Mexican Water Lily has engulfed large sections of the lake, particlularly near the King Street entrance, and is spreading throughout the lake.

Susan and Steven Barton have been trying to get the council to remove the invasive lily and remove silt from the lake for the past eight years. They say the weed was introduced to the lake via the council’s stormwater system during flooding about 10 years ago.

“It was only a small patch when I told (open spaces operations manager) Ian Moloney about it eight years ago. Now it has taken over large areas of the lake and is spreading southward," he said.

“At the King Street end [of the lake] there has been, particularly over the summer months, a horrific stench emanating from decaying vegetation and dead wildlife such as fish, ducks, eels and algal bloom.”

The couple say the area has been neglected to the point where people urinate in bushes because there are no nearby toilets.

Council Response 

Ian Molony said the council had allocated budget in the draft Long Term Plan 2024-2034 to implement recommendations from a report by environmental scientist Keith Hamill, Sullivan Lake Water Quality & Options for Improvement.

Through the long-term plan deliberations process, this funding had been deferred to the 2025-2026 financial year.

“Budgeted works will commence after July 2025 and include mechanical removal of the water lilies and organic sediments starting at the King Street end of the lake.

“This will be followed by bottom lining to prevent regrowth. Further harvesting of macrophytes (aquatic plants) will also be undertaken within the lake beyond the water lilies.

“From July 2026, works to establish wetland areas and further harvesting of macrophytes will be carried out.”

Though she lives across town, youngster Quinn Johnston is a regular visitor and loves to feed the ducks in the area around the edge of the lake that Whakatāne District Council keeps clear of lilies. 

He said there were no plans to spray all the lilies this year.

“The decomposition of these will exacerbate the poor water quality and create odour issues, particularly with the warmer temperatures. Council staff, however, will continue to maintain the visible perimeter between the bank and the lilies through spraying.”

LDR is local body journalism co-funded by RNZ and NZ On Air.