Gold Coast City Council’s project aimed to reduce the impact of current and future floods within the Nerang River System and ultimately challenged conventional thinking on flood planning in Queensland.
Following the raising of the Hinze Dam wall in 2012, GCCC was expected to comply with traditional flood planning laws by lowering flood planning levels to reflect the reduced flood impact on the community. To ensure the resilience gained by raising the dam wall was not lost in the following years, GCCC conducted research which revealed the long term benefits in keeping planning levels as they were.
Through the use of evidence-based research and community consultation, GCCC gained the support of the community, who chose not to lower flood planning levels. By showing leadership and engaging with the community, the flood protection offered to the communities surrounding the Nerang River will extend beyond 2060. Had planning levels been lowered, the benefit of raising the dam would have been relatively short-lived.
After three severe floods in less than 24 months, Council sought a permanent, cost effective solution to the temporary levees erected and dismantled for each flood from 2010 to 2012. It was also desired to protect more homes than the temporary levees had the capability to.
Flood mapping for the whole of shire was undertaken and progressed to detailed analysis for St George. This flood mapping formed the basis for decision making about the possibility and location of levee/s.
As a result, an earthen levee was constructed August 2013 - October 2013 (Stage 1), followed by a block wall November 2013 - February 2014 (Stage 2). Earthen levees left in place from previous floods connected the various sections. Four streets were currently being raised in St George.
It is also necessary to identify prime areas of population at risk and implement developmental controls to ensure any future development responds to the level of risk the area faces.
Government funding is also being allocated to homes outside the levee to reduce the risk of over floor flooding by raising homes or installing private mitigation devices. There were 22 projects underway at the time of nomination.
Highly Commended: Lake Macquarie City Council
The 'Development Guidelines for Resilient Housing in Lake Macquarie' is an innovative project that allows Council and developers to ensure new homes built in existing suburbs will be at a reduced risk from flooding. It gives builders and developers design options for homes that can be adapted to higher flood levels and increased flood frequencies resulting from the effects of rising sea levels. The Guidelines have been included in the Lake Macquarie Development Control Plan to complement more traditional controls on buildings in flood prone areas such as floor height requirements and set-backs from the lake foreshore.
The Guidelines apply four principles for the design of flood-resilient housing:
1. Site analysis and design - to ensure the building is located on the safest part of the site and leaves room for protection works
2. Relocation - buildings can be disassembled and moved to safety if there is an increase in flood risk as a result of rising sea levels
3. Raising of floor height - buildings can be raised or have their floor levels altered to prevent over-floor flooding if flood levels increase
4. Redundancy - buildings are designed to allow a change of use of ground floors as flood levels increase
The guidelines add to the flood-risk management options available to Council and developers. They apply to infill or replacement developments in established suburbs, so do not encourage additional development in flood-prone areas. Every year Council approves 40-60 applications to renovate or replace homes on flood-prone land. By applying development controls and/or resilient building guidelines based on the flood hazard over the life of the new asset (50 - 100 years) the new buildings will comply with flood risk thresholds over their useful life, even if sea levels rise as predicted.
This project allows continued safe enjoyment of living in foreshore suburbs around the lake while managing the predicted increase in flood risk resulting from rising sea levels.
Highly Commended: Launceston Flood Authority
This $55 million initiative funded by the Australian, Tasmanian and Local Governments, is reconstructing the levees of the Launceston Flood Protection Scheme to reduce the risks against potentially devastating and catastrophic impacts of flooding. The project includes community awareness and flood preparedness delivered by the Council through a community flood education strategy.
Launceston is Tasmania's second largest city: a city of some 70,000 people, with a portion of its CBD and major northern suburb, Invermay, situated on the natural floodplain at the confluence of the Tamar River estuary and the North and South Esk Rivers.
Launceston has been subject to 35 significant floods since the early 1800's, with the 1929 flood reputedly being the worst, displacing over 4000 residents resulting in 22 deaths and rendering many buildings uninhabitable. Most of Invermay and much of the lower CBD was inundated during this flood.
Invermay is a thriving inner suburb containing cultural icons such as Launceston's Queen Victoria Museum and Art Gallery, a University Campus and Aurora Stadium. The flood prone area of the CBD is a mixture of residential and commercial enterprises and is home to Boags Brewery and historic buildings, many associated with Launceston's port history.
Much of Invermay is below the high tide level and is reliant upon levees for its sustainability. In the event of a major flood today, up to 1,660 properties would be inundated and up to 7,000 people would require emergency accommodation for potentially several months.
By reconstructing the levees of the Launceston Flood Protection Scheme, flood protection to the 95th percentile; 1 in 200 ARI flood has been afforded to the community, providing increased community resistance and resilience, greater opportunity for appropriate development and enhanced lifestyle based around the City's iconic river systems.