In September 2014, the Brown Hill Keswick Creek (BHKC) Stormwater Project released the ‘Part B Report’, detailing investigations into eight options to mitigate flood risks in upper Brown Hill Creek.
A brief summary of the report can be found here (629kb). The full Part B Report and Appendices can be viewed at right. All options involve two types of work along upper Brown Hill Creek to reduce the risk of flooding during high stormwater flows:
- Creek capacity upgrade works in critical sections (which vary for the eight options) – to increase the capacity of the creek so it can carry more water; and
- Creek rehabilitation works along its full length – to assist the flow of water along the creek and improve its biodiversity.
In addition, all of the options include undertaking creek rehabilitation works to rehabilitate the creek towards achieving ‘good condition’ in order to assist flow capacity along the full length of upper Brown Hill Creek.
Under the Natural Resources Management Act, creek owners are responsible for maintaining the creek in good condition. This is explained in the brochure: ‘Urban Creeks – A property owner’s guide to managing healthy urban creeks’ produced by the Adelaide and Mount Lofty Ranges Natural Resources Management Board (AMLRNRMB) in conjunction with the City of Burnside, which can be accessed here.
The Part B Report, prepared by the BHKC Stormwater Project, identifies Option D as the preferred option.
This option involves upgrading the capacity of the creek at critical sections over the full length of upper Brown Hill Creek, as well as upgrading specific choke points such as bridges.
Option D was identified as the preferred option for Part B flood mitigation works as:
- It has the lowest capital cost ($35.5m) and lowest ongoing maintenance costs compared to the other seven options
- It provides the required (100 year ARI) level of flood protection
- For shorter duration storms it provides a higher than 100 year ARI level of flood protection
- It satisfies the project councils’ endorsed position to give preference to a feasible ‘no dam’ solution
- It does not require bypass culverts in suburban streets
- It is within the budgeted cost for Part B works as estimated in the SMP 2012 Stormwater Management Plan
- It preserves existing sites of heritage significance
Final decision making process
A six-week consultation process on the Brown Hill Keswick Creek Stormwater Project’s Part B Report for upper Brown Hill Creek occurred between May 13 and June 23, 2015. The outcomes of the community consultation process were then reported to the five catchment councils. The full community consultation report can be accessed here.
In September 2015, the five catchment councils unanimously agreed on Option D – ‘Creek Capacity Upgrade’ – as the preferred option for Part B Works, enabling the project’s Stormwater Management Plan to be finalised for the Stormwater Management Authority’s approval.