Wivenhoe Dam optimisation study out for public consultation
THE State Government is looking at removing the rural flood mitigation strategy as part of its long-term optimisation plans for Wivenhoe and Somerset dams.
A public meeting in Fernvale on Thursday night went through the discussion paper for the optimisation of the dams, which was one of the recommendations from the Queensland Flood Commission of Inquiry.
The paper discusses the three flood strategies for Wivenhoe: a rural flood mitigation strategy which keeps open the low-level brides; an urban mitigation strategy which protects houses and buildings in a larger flood; and a dam safety strategy which protects the dam structure from rare and extreme floods.
Currently 37% of the dam is used to store water, 5% is used to enforce the rural flood mitigation, 24% to enforce urban flood mitigation and the uppermost 34% protects the dam wall from extreme events.
In the new strategy favoured by the government, the 5% rural strategy is removed while the urban strategy increases to 35% while the uppermost dam safety margin is reduced to 28%.
The discussion paper said the advantage of this strategy is that it would provide more room to save houses and buildings in Brisbane and Ipswich and it would link up with a new upper flow limit 16 hours downstream of Wivenhoe at Mogill (after the Lockyer Ck and Bremer River join the Brisbane River), to avoid the possible need for more damaging releases for dam safety.
The downside is more frequent inundation of low-lying crossings at Savages Crossing, Colleges Crossing, Burtons Bridge and Kholo Bridge.
The dam operators would still aim to keep open the Geoff Fisher bridge on the Brisbane Valley Highway at Fernvale as part of this strategy.
The public consultation period is open until June 30 and comments and feedback will be included in the final report due to be released later this year.