The future of a popular swimming pontoon at Cromwell’s Alpha Street Reserve is in limbo after safety concerns forced its removal last week just months after it underwent specialist repairs.

Central Otago District Council (CODC) made the call to haul the structure from the Lake Dunstan swimming area last Wednesday (January 7) after reports it was potentially taking on water.

The council was alerted to the issue on Tuesday, January 6, by several members of the public.

Staff were onsite that afternoon to erect emergency signage prohibiting use of the structure, before removing it entirely the following day.

“Part of the pontoon appeared to be taking on water, making the structure unstable,” the CODC parks manager told The Central App on Monday.

“With a large number of people using it at the same time, the added weight caused the pontoon to partially submerge and tilt significantly, creating a safety risk.”

Parents at the lake while the pontoon was in use last week said they were concerned the structure could flip, or swimmers could be hit or caught underneath as it tilted out of the water at a sharp angle as people played on it. 

The Alpha Street pontoon appears to be taking on water, shortly before it was removed for assessment last week. Image: The Central App

The structure is now at a contractor’s yard for assessment, but its future remains undecided.

“Once the cause of the issue has been confirmed, a decision will be made on whether it will be repaired, replaced, or another solution implemented,” the parks manager said.

The failure comes despite a major maintenance program carried out last year.

CODC owns and maintains four swimming pontoons on Lake Dunstan - at Lowburn, Bannockburn, and Burton Creek, in addition to the one at Alpha Street - all of which were serviced approximately six months ago.

“All pontoons were removed from the water during winter 2025 for inspection and repairs by a specialist contractor,” the manager said.

Following those repairs, the council said the pontoons were thoroughly inspected and reinstalled in spring.

All four pontoons undergo the same annual inspection cycle and, while the Alpha Street site is empty for now, the other three remain in use.

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