Report identifies “creek capacity upgrade” as preferred option
Upgrading the capacity of upper Brown Hill Creek has been identified as the preferred option for stormwater works in the region to help mitigate flood risks, according to a new project report.
The Brown Hill Keswick Creek Stormwater Project – a collaboration between Adelaide, Burnside, Mitcham, Unley and West Torrens councils – has released its Part B Report as part of its broader Stormwater Management Plan.
The report considers eight options for potential flood mitigation works in upper Brown Hill Creek that have been assessed on technical feasibility, non-technical aspects and financial considerations.
All eight options include rehabilitation works along the full length of upper Brown Hill Creek from Anzac Highway to Brownhill Creek Caravan and Holiday Park to help restore the creek to good condition.
Of the eight options investigated, the report identifies a preferred “creek capacity upgrade” option (Option D) because:
- It is effective in providing the required level of flood protection;
- It satisfies the catchment councils’ endorsed position to give preference to a feasible ‘no dam’ solution;
- It does not require bypass culverts in suburban streets;
- It preserves existing sites of heritage significance;
- It represents the lowest capital cost ($35.5 million) and lowest ongoing maintenance costs compared to the other seven options; and
- It is within the budgeted cost for Part B works as estimated in the Stormwater Management Plan.
Project Chair of the Brown Hill Keswick Creek Stormwater Project, Terry Buss, says investigations into Part B works have benefitted from revised rainfall predictions released last year by the Bureau of Meteorology.
“The updated hydrology (rainfall) data and runoff forecasts have led to updated assessments of creek channel capacity, as well as new hydraulic modelling and floodplain mapping,” he said.
“The new rainfall data and upgraded floodplain modelling indicate a slightly reduced flood risk to the region, and have led our investigation to give preference to a creek capacity upgrade option for upper Brown Hill Creek.
“The creek capacity upgrade option includes widening the creek bed or modifying creek banks at critical points to ensure there is sufficient capacity for one-in-100-year peak flows to be conveyed along the full length of upper Brown Hill Creek.”
Prior to any decision about works associated with the management of stormwater for upper Brown Hill Creek, the project will undertake a community consultation process following upcoming council elections where residents will be given opportunities to discuss the report’s findings with project staff and provide feedback on proposed works.
“The next step will be for the five catchment councils and the public to review the proposed options for upper Brown Hill Creek and provide feedback through a formal community consultation process, which is expected to occur early next year,” said Mr Buss.
“All five councils will then be provided with the outcomes of the community consultation process and upon review determine a position before making a final recommendation to the State Government’s Stormwater Management Authority on the desired options.”
For more information or to view the Part B Report, visit www.bhkcstormwater.com.au.
About the Brown Hill Keswick Creek Stormwater Project
The Brown Hill Keswick Creek Stormwater Project is a collaboration between Adelaide, Burnside, Mitcham, Unley and West Torrens councils to develop and implement an effective stormwater management plan to improve the standard of flood protection for homes, businesses and public facilities across the catchment.
The project has developed a Stormwater Management Plan, approved by the Stormwater Management Authority in February 2013, which includes two key sections: “Part A” works comprising about 80% of the program which have already commenced, and “Part B” works for upper Brown Hill Creek that are the subject of current investigations.