Lake Taupo just trickling down river

By JO-MARIE BROWN

Taupo is having its driest spell in 20 years and Lake Taupo's rapidly receding waters are causing headaches for both power generators and boaties.

Just 166mm of rain fell in Taupo between January and April this year - about half the normal rainfall and the lowest amount recorded by the National Institute of Water and Atmospheric Research for that period since 1983.

Mighty River Power chief executive Doug Heffernan said the company's nine power stations along the Waikato River had been reduced to about 30 per cent capacity for the past month because of Lake Taupo's low level.

The hydro-electricity generator had to allow a minimum amount of water to flow through to meet environmental obligations but "there's less water flowing into Lake Taupo than we're required to put down the Waikato River so that's why the lake continues to fall".

At the lake's southern end, low river levels have forced Genesis Power to stop diverting water from the Whanganui and Tongariro rivers to its power stations.

Normally that water would then flow into Lake Taupo and its absence is contributing to the problem.

Four of the lake's 19 boat ramps were unusable because the water was too shallow and another two were marginal, said Taupo harbourmaster Les Porter.

"All I would say to boaties is make sure you use a ramp that will cope with your boat and trailer and also be very careful out on the lake.

"In places where they used to drive their boats across with total safety, there could be a rock lurking close to the surface so they'll need to consult their navigation charts," Mr Porter said.

Lake Taupo is just 24cm above its minimum control level for power generation but Mighty River Power is confident the level will not drop that low.

"There's nothing to suggest that the inflows would be that bad," Dr Heffernan said.

Niwa scientist Dr Jim Salinger said Taupo could expect a dry May but normal rainfall should resume in June and July.