Flood gates opened on dam wall option
A PROPOSAL to raise the height of Rocky Creek Dam has been put back on the agenda for Rous Water.
Cr Sue Meehan put forward a successful notice of motion at a meeting last week requesting further information about the feasibility of raising the wall as part of Rous Water's Future Water Strategy.
Technical services director Wayne Franklin said the strategy, which aims to deliver water security for the region to 2060, is considering a whole raft of measures including desalination, using reclaimed storm water and a second dam at Dunoon, along with strategies to reduce demand.
He said all the options have been run through a "coarse filter" by the project reference group (a group of stakeholders and residents) and the option for raising the wall at Rocky Creek Dam was deemed unviable.
"Based on the criteria, we determined that it was unlikely to be a suitable method... The key reasons were that Rocky Creek Dam was built in 1953 and there is no outlet arrangement for environmental flow releases... If we raise the wall, there would be a requirement from State Government to make environmental flow part of a revised licence for the dam.
"We did some hydrological modelling to determine the increased capacity, offset by the environmental flow release, and in terms of the increase in secure yield, it was only about 1000 megalitres a year. We are looking for as much as an additional 6000 megalitres... So in terms of meeting that, it fell well short of the mark."
Mr Franklin said the other reason it had previously been rejected is that it would require flooding a significant part of the Nightcap National Park, which is World Heritage listed and "may not be legally possible".
However, the option is now back on the table and will be considered alongside all of the other proposals.
A draft report by consultants MWH is expected to be prepared by mid-year, considering the triple bottom line of economic, environmental and social factors for each option.
"Raising Rocky Creek Dam will now be assessed on those criteria, the same as all the other options," Mr Franklin said.
He said many people considered a second dam at Dunoon "a foregone conclusion" but he said at this stage it was not.
"It is only one of the options."