While it’s yet to reach its nadir, water in Lake Taupō is well below seasonal levels, leaving boaties high and dry and electricity generators scanning the skies.

But there’s no rain on the horizon to provide a top-up.

The average for this time of the year, 356.43masl (metres above sea level), was usually 40cm higher than the current lake level, said Mercury Energy.

A company spokesperson said an extended period of low inflows into the Taupō catchment was due to comparatively little rain falling in the ‘right place’.

“However, it’s important to remember that this time of the year, after summer’s traditional dry weather, is when the lake will generally be at its lowest.”

Mercury is responsible for managing the level of the lake, which provides the primary storage for the Waikato River’s series of eight dams and nine power stations.

It has to operate within a maximum high and low (a range of 1.4 metres). The level on May 25 was 17cm above the minimum.

Water flowing down the Waikato, the lake’s only outlet, equates to 1 per cent of the lake’s total volume

Mercury said none of the forecasts it looked at were currently predicting a major rain event.

The unusually low lake level posed a number of problems for the boating public, said Taupō harbourmaster Heath Cairns, with some boat ramps unusable.

“Even if the end of the ramps, effectively the lakebed, was excavated to allow boats to be floated off their trailer, boats would still hit the lakebed as they transited out into the lake,” he said.

He was advising boaties, unless launching smaller, lighter craft, to use Acacia Bay South, Nukuhau, Two Mile Bay, Motutere and Motuoapa Marina – with caution.

“Other ramps have limited operational ability, and some simply can’t be used at all… Four-wheel-drive vehicles with higher ground clearance and better traction would be a safer option.”

Some larger commercial craft were now touching the bottom at their marina berths or when using the channel out to the lake, said Cairns.

“Although I can certainly empathise with these operators, unfortunately there is no quick fix.”

Niwa’s climate outlook to July is forecasting below or near normal rainfall throughout the country, except in the Far North, and the forecaster noted it was possible long dry spells would continue from autumn into early winter.

“Groundwater and dam level recharge and increases in river flow and soil moisture will likely be less pronounced than normal,” said Niwa.

Compounding the issue is the traditional peak in winter energy demand, though Mercury said the increased use of heaters and electric blankets was a predictable seasonal change.

“And we plan this into our careful operation of Lake Taupō and the hydro lake levels, and the flow of the river.

“The South Island hydro lakes are also below average at the moment but have been filling up since a low point in mid-April. The hydro storage in the South Island is now up to 76 per cent of average for this time of year.”

This contrasted with Lake Taupō’s 31 per cent of average.

Yet to be determined downstream is the draw of an extra 150 million litres of water per day from the Waikato, to top up Auckland’s municipal supply.

The issue is the subject of a board of inquiry hearing into Watercare Services Limited’s resource consent application which, if successful, will move it up to a total take of 300 million litres of river water per day.

The Waikato River Authority, Hamilton City Council and Waipā District Council have indicated they will oppose the move and Waikato Regional Council chairman Russ Rimmington​ has said he supported the city’s draft position, saying Auckland had to learn to stand on its own two feet.

Written evidence, following Watercare’s initial submissions, is due from the regional council by June 4, with written copies of further oral submissions from others due by June 18

The board – engaged by the minister for environment to consider the application – is not expected to make a final decision until November 2021.

Credit:Stuff.co.nz