Callide Dam Safely Passes Flood of Record
13 Feb 2013
During January 2013, Callide Dam was closely monitored to ensure that excess water was being safely managed via controlled water releases through the dam gates as it passed a flood of record.
SunWater Acting General Manager Infrastructure Management Tim Donaghy said that the dam safely passed a flood of record and handled a significantly larger volume of water than the previous flood of record in 2011.
“Callide Dam has six radial gates that are each 9m high by 6m wide. At the peak of the previous flood event in 2011 only the 2 central pair of gates were opened at around 17 cm passing approx. 1,750ML of water per day. In comparison, at the peak of the recent event in January 2013 all six gates were open at around 3.2m, passing an estimated173,000ML of water per day,” Mr Donaghy said.
“With regard to the nearby Kroombit Dam, it also passed a flood of record in January 2013 and the peak flow of water was 1.6m above the spillway crest passing approx. 99,000ML of water per day via the spillway which is nearly 7.5 times the capacity of the dam,” he said.
In December 2012, the operating level for Callide Dam was revised following regular monitoring undertaken after the January 2011 flood event that detected an increased rate of seepage in some sections of the dam embankment.
Mr Donaghy said that as a precautionary measure leading into the wet season, SunWater adopted a reduced operating full supply level of 214m AHD, which is 2.1m below the full supply level. This means that the dam will now be considered to be full when it reaches 214m AHD, or the equivalent to 82% of the Full Supply Level.
At the time SunWater notified customers, the Dam Safety Regulator, Banana Shire Council, high priority irrigation customers and the Department of Environment and Water Supply of this decision.
During the course of 2013 SunWater will undertake further assessments of the embankment to determine what is required to bring the dam back to its previous operating level without compromising its safety.
“The dam performed extremely well during the recent event and SunWater would like to assure the community that the dam is safe,” he said.
Mr Donaghy added that while SunWater has received queries about whether water could be released from Callide, Kroombit, Cania or any other SunWater dams to mitigate flooding, it is important to note that these dams are not designed or currently operated to provide downstream flood mitigation, and therefore pre-emptive water released for the purposes of flood mitigation cannot be made without extensive consultation with the community, and particularly with those water users whose supplies could be potentially affected by such actions.
“Callide, Kroombit, Cania and the other SunWater dams in the region are designed to store water to their intended capacity and then safely divert any excess water inflows over the spillways, through release gates or outlet works,” he said.
SunWater is aware of community concerns regarding the dam during this most recent significant wet weather event and is undertaking a post event review of the dam operations as a matter of course.