Operation of the scheme
Weirs across the natural lake outlets will establish
a spill height at the existing mean annual lake level. Natural
fluctuations in lake height above this level, which invariably
occur during flood events, will remain unaffected.
The maximum drawdown of the lake during generation will not
exceed a level 920mm below the mean annual leve which is the
lakes lowest natural level. Normal daily operation is expected
to maintain the lower lake level well above this minimum.
A minimum flow of 1000 litres per second measured at the existing
slack line just upstream of the east branch will be maintained
at all times.
In order to improve efficiency the generator will, in normal
operation, either run at full power or be shut down to conserve
water for periods of high electricity demand. Occasionally
the generator may be run at partial power to maintain the
minimum lake level if lake inflows are low.