Spring rain inflows and low outflows have allowed Lake Hawea to replenish and the level of the hydro storage lake is the highest recorded for almost three months.
A period of sustained spring rainfall in the Upper Clutha has raised the lake above 339 metres above sea level for the first time since mid-June.
Contact Energy has been limiting outflows from the lake to less than 12 cumecs for the past week, which also helped raise the lake.
The improving South Island hydro generation position is reflected by the fact power is being sent to the North Island for the first time for months, resulting in falling wholesale electricity prices.
The Upper Waitaki hydro-electric lakes of Tekapo and Pukaki have also benefited.
Lake Tekapo is about 30% full and Lake Pukaki about 21% full. In Fiordland, Lake Te Anau is about 58% full and rising, while Manapouri is 51% full.
