Increased risk to Lake Taupō and Waikato River users due to record high levels

The Waikato River is running fast and high due to a very wet year in Lake Taupō. Photo / Supplied

Higher lake levels in Lake Taupō and stronger flows in the Waikato River are prompting calls for swimmers and river and lake users to take extra care this summer.

Floating from the Control Gates Bridge to a reserve just above the Huka Falls is a popular activity for thousands of people each summer but conditions are far more dangerous than in previous years, says management authorities.

Lake Taupō Harbourmaster Jamie Grant says that with the Waikato River currently running at about twice its usual volume, attempting a river float trip would be too dangerous.

The wettest winter since records began in 1905 has meant Lake Taupō was just below full, and in turn the Taupō Gates are fully open, with maximum flow in the Waikato River, significantly higher and stronger than usual.

“My advice would be not to do it at these high lake levels. It’s really dangerous and Mercury can’t slow [the river] down, the lake is too full and for pretty much the last three months it has been running at maximum.”

Mercury, which manages the Waikato hydro system, is also warning swimmers and other lake and river users to be aware of the risks of the stronger currents and changeable, faster flows.

Mercury general manager portfolio Phil Gibson says people should follow water safety rules: to know the weather and water conditions before they get in, to be aware that this summer’s conditions are likely to be different than what you may be used to, to watch out for others particularly children, and use equipment such as lifejackets correctly.

North of Karāpiro, varying water levels may mean there will be downstream impact on low-lying land including some pathways and the Grantham St carpark in Hamilton.

There are more drownings in rivers than any other environment in New Zealand and 83 drownings have been recorded in 2022 so far, against 78 at the same time in 2021.

Taupō District Mayor David Trewavas said the river can be more hazardous than people expect, particularly at high flows, and he urged river and lake users to ensure they had the proper safety gear and knew what to expect.

Water levels at Lake Taupō are the highest for this time of year that they have been since Mercury took over management of the Waikato Hydro System in 1999.

Gibson said swimmers should be aware of the potential for stronger currents and changeable, faster flows.

“Jumping into the river and lake are part of the Kiwi summer, but we are reminding swimmers and other lake and river users to take into account the higher water levels and stronger flows.

“We strongly encourage everyone to follow the usual water safety rules: know the weather and water conditions before you get in – and these are likely to be different than what you may be used to, watch out for others particularly children, and use equipment such as lifejackets correctly.”

The higher flows also have the potential to impact the Aratiatia Rapids spillway release, increasing the volume of water in the hazardous no-swim zone.

Mercury’s Hamilton Control Room monitors and influences the lake and river flows using the Taupō Gates and the eight hydro power dams in the Waikato Hydro System.

“We’re coming out of the wettest winter we’ve had since records began in 1905,” Gibson said.

“The team are on deck 24/7 across the Christmas period to manage this unusual and challenging situation.”

Lake levels at Taupō are still within Mercury’s allowed operating range, but the Taupō Gates, where the lake waters enter the Waikato River, are now fully open with maximum flow downriver.

Inflows to Lake Taupō and tributaries feeding the Waikato River system have been above the 80th percentile range for the last six months.

On-shore winds, combined with higher lake levels might mean it feels like high waves on the shoreline at this time.