Effective stormwater management and flood mitigation is one of the most significant issues facing South Australia’s City of Charles Sturt and its residents. Many suburbs within the City have a long history of flooding because the land is flat and close to sea level and much of the stormwater infrastructure is ageing.
To reduce the risk of flooding, Council has released the first computer generated flood plain mapping to be produced as part of Council’s Urban Stormwater Master Plan (USMP). The USMP was developed in 2002 as a holistic approach to effective stormwater management, including flood mitigation, improving water quality, urban amenity and using stormwater for community benefit. It involves a detailed analysis of every water catchment, plus flood plain mapping.
So far, five catchments representing close to 50 per cent of the City have been analysed and, of these, three have been mapped. The mapping of these catchment areas indicates that 20 per cent of properties in these areas would be at risk of flooding in a one in 100 year rainfall event.
“This mapping is ground breaking because the technology is new and we are the first Council in Australia to use it on such a significant scale,” Charles Sturt Mayor, Harold Anderson said. “For the first time we have comprehensive information about flood risk so we can implement strategies to deal with the problem and plan for future development over the next 50 years.”
Mapping information can also assist organisations involved in handling emergency work during floods, such as the State Emergency Service, Metropolitan Fire Service and police.
Significant funding will be required to replace or upgrade stormwater infrastructure in Charles Sturt. However stormwater engineers, Tonkin Consulting, said that if Council does nothing, the damage bill from a major flood could be many times greater than the cost of rectification.
A cost benefit analysis is currently underway to determine infrastructure priorities and the likely cost of the work required to reduce the risk of major flooding. Council has already begun discussions with the State Government about sharing the cost, which could amount to tens of millions of dollars.
The City of Charles Sturt is not alone with this problem. The Metropolitan Adelaide Stormwater Management Study, a joint State and Local Government study conducted in 2004, estimated that more than $160 million worth of stormwater drainage work is required across the metropolitan area. Most metropolitan Councils have now commissioned, or will be commissioning, USMPs.
For further information contact Peter Lockett, City of Charles Sturt CEO, on (08) 8408 1101.
