Major repairs to the banks of Purga Creek at Peak Crossing School
26 Jul 2012
The January 2011 flood left South East Queenslanders with many challenges as they rebuilt lives, farms and infrastructure. One challenge that is less well known, but has major impacts on water supply and the health of our rivers and Moreton Bay was the erosion damage to river banks.
Serious stream and river bank erosion occurred throughout Lockyer Creek, the Mid and Upper Brisbane Rivers, the Stanley River and the northern Bremer including Purga Creek. Many landowners adjoining major rivers and streams, including the Peak Crossing Primary School on Purga Creek, lost valuable land, fences and irrigation equipment and many rural roads and bridges were damaged.
Bank erosion during the floods resulted in many millions of tonnes of sediment being moved into streams, rivers and, in many cases, Moreton Bay. These sediments cost the community dearly. They increase the cost of producing drinking water, fill in dams and reservoirs, reduce the health of streams and rivers and pollute Moreton Bay.
For the Peak Crossing School, the January 2011 floods eroded a 70 meter Reach of Purga Creek along the school boundary, leaving a 7 meter sheer cliff that posed significant risks to student safety, threatened school infrastructure and, if left un-remediated, would result in future severe loss of school lands, the school tennis court and school buildings.
Following the floods, Seqwater approached SEQ Catchments, a not-for-profit company whose focus is to protect the natural resource values of the region, for assistance in helping repair the bank erosion at the Lowood Pump Station.
SEQ Catchments Chief Executive Officer, Simon Warner, explains "prior to the floods, the banks were steep and grassed with only occasional trees: They did not have the number and diversity of trees and shrubs whose roots would otherwise bind the top couple of metres of soil. As a result, the banks were vulnerable to the high flows that were experienced in Purga Creek during the floods".
The more complex challenge for SEQ Catchments was to determine how it could be repaired and how the resilience of the creek could be increased to guard against future damage. SEQ Catchments sought a range of expert advice to develop a restoration plan that relied on strengthening and battering the damaged banks and building natural resilience through extensive planting of riparian vegetation.
The restoration plan was of significant interest to the Queensland Reconstruction Authority, which had a mandate to help the community rebuild following the floods. With NDRRA funding from the Reconstruction Authority and with the help of the school Parents & Citizens Association, which relocated the boundary fences and a number of small buildings, SEQ Catchments was able to remediate the site.
Head of the Reconstruction Authority, Major General Dick Wilson, inspected the works with Scenic Rim Regional Council Mayor, John Brent and SEQ Catchments' Chair, Robert Smith; and planted a ceremonial tree on the banks with School Captains, Mitchell Lait and Kensey McNamara.
Major General Dick Wilson said, "It’s great that SEQ Catchments was able to engage local contractors, Klan Brothers, to manage the earthworks and Thomas Bell to undertake the tree planting. Mark Klan not only operated the machinery, but he went to the school as does his daughter; and his father was taught in one of the old school buildings that was moved onto the school grounds."
"SEQ Catchments has done a great job with the site, Mayor John Brent said. “Every year the trees and shrubs can mature on the restored banks, the better able they will be to resist floods like those we saw in January 2011. Importantly these works have helped us build the knowledge to repair other degraded rivers throughout South-east Queensland".
On 31 July SEQ Catchments took out honours in The Australian Business Awards 2012, winning the Environmental Sustainability category in recognition of its ground breaking work in the natural resource management (NRM) sector. The award specifically recognises SEQ Catchments' achievements in working with the community to protect and restore South East Queensland's unique natural environment and biodiversity.