CEO of the Goulburn Broken Catchment Management Authority, Bill O’Kane has rejected
claims by the Member for Benalla that the decommissioning of Lake Mokoan
will have a major impact on flooding in Benalla.
current operational rules see the diversion of up to 2500 mgl a day from the Broken River
and Holland Creek into Lake Mokoan. Mr O’Kane said the diversions do not
materially affect flood heights in Benalla in a major flood. This was confirmed in the Benalla flood study
conducted by Cardno Willing after the 1993 floods.
study concluded that even if the Lake
Mokoan inlet channel was
1km wide it would only lower flood heights in Benalla in a major event by less
than 5cm. This makes sense because the Broken River
peaked in Benalla during the 1993 event at 112,000Ml/day and often the channel
is not being operated during major floods.
O’Kane did agree with Mr Sykes that the decommissioning of Lake Mokoan
will have an impact on the frequency and height of minor floods.
be healthy, rivers must flood and to increase the height and frequency of minor
floods without increasing the height and frequency of major floods gives us the
best of both worlds.”
O’Kane said the1963 Parliamentary Report into Lake Nillahcootie
clearly states that its purpose was for water harvesting only.
Willing looked into this issue too and concluded that even if Nillahcootie was
empty at the beginning of a major flood event, it would have a negligible
impact on flood heights in Benalla.
more information telephone Bill O’Kane (or his personal assistant Kathy Fuller)
at the GBCMA on 58 201100.