The 2016 stormwater management plan (SMP) is designed to substantially reduce the number of properties within the catchment that would be affected by very large flood events, including a 100 Year ARI flood.
A 100 Year ARI flood is a flood that will occur on average once every 100 years, and has a 1 in 100 (1%) chance of occurring in any given year. It is the most commonly applied standard in Australia for providing an acceptable level of flood protection for the community.
The 2016 SMP was submitted to the Stormwater Management Authority for approval in March 2016 and builds on the 2012 SMP (gazetted as the SMP in 2013).
It includes recommended flood mitigation infrastructure works in two categories, Part A Works and Part B Works.
Part A Works comprise the following projects to mitigate flooding generated from the mainly urban sub-catchment of Glen Osmond, Parklands and Keswick Creeks:
- South Park Lands and Glenside detention basins (on Parklands Creek)
- Lower Brown Hill Creek upgrade (downstream of Anzac Highway)
- Flow Diversions from Keswick Creek to Brown Hill Creek (an underground culvert system principally along Le Hunte and Leader Streets, Wayville and along Anzac Highway)
- Brown Hill Creek upgrade – Area 1 (between Forestville Reserve to Anzac Highway)
- Ridge Park flood control dam (combined with the Unley Council stormwater harvesting scheme)
- Glen Osmond Creek minor upgrade works (along Glen Osmond Creek)
In addition to the above works, the Department of Planning, Transport and Infrastructure (DPTI) has constructed the Brown Hill Creek diversion culvert as part of its Goodwood Junction rail upgrade project. These works are outlined in Section 10.7 of the 2016 Stormwater Management Plan.
Part B Works are applicable to the upper Brown Hill Creek part of the catchment (upstream of Forestville Reserve). To determine the works in this part of the catchment, further investigations were undertaken based on initial options identified in the 2012 SMP. The findings of these investigations are detailed in the Part B Report.
The 2016 SMP also proposes other initiatives to help reduce the impact of major flooding over the catchment, including:
- Improved planning policies and assessment processes to ensure that new development is designed to reduce flood risk and potential exposure to flooding;
- Greater use of water sensitive urban design in streetscapes and new developments;
- Community awareness about flood risk and flood preparedness;
- Clarifying responsibilities and promoting good practice for maintenance of creek channels; and
- Project funding for water quality works.
The 2016 SMP also identifies environmental and community benefits that could be achieved in addition to flood protection measures, including improved biodiversity, creek rehabilitation and improved recreational amenity in open space areas traversed by watercourses.