December 8, 2014
The South Burnett Regional Council has begun work on Gordonbrook Dam’s spillway to repair damage caused by the 2013 floods.
Water flowing over the spillway during the floods scoured out the northern side of its bank, eroding away tons of soil.
The water also scoured out large holes in the spillway’s bedrock floor, some more than four metres deep.
At their peak, about 2800 megalitres of floodwater flowed over the spillway every hour.
The erosion of the northern embankment and the floor would continue in future floods, causing even more of the bank to collapse into the Stuart River, without remediation work.
Water Portfolio chair Cr Barry Green said the first stage of repair work would involve using shotcrete to rebuild the northern embankment wall.
Shotcrete is projected concrete which undergoes placement and compaction at the same time.
“This $1.245 million project is being funded through Natural Disaster Relief and Recovery Arrangements,” Cr Green said.
Full remediation of the spillway is expected to cost $4.5 million.
However most of the funds for the project will come from the Federal and State governments.
The Council’s contribution to remediation work is expected to be about $80,000.
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Gordonbrook Dam was originally built in 1941 to provide water for Kingaroy’s RAAF training base.
In 1987, the dam wall was raised and the catchment area expanded to 229ha to meet increasing water supply demands.
In 2007, a $2.4 million emergency pipeline was built to link Gordonbrook to Boondooma Dam when Gordonbrook looked like it might run dry during drought conditions.
In February, water from Boondooma Dam was used to supply Kingaroy when elevated levels of trihalomethane was discovered in Gordonbrook’s water.
This problem is expected to be fixed late next year when upgrades to the Gordonbrook water treatment plant are completed.
Until that time, Kingaroy will continue to be supplied with water drawn from Boondooma Dam.