The 2012 Stormwater Management Plan for the Brown Hill Keswick Creek catchment recommended an upgrade to the Lower Brown Hill Creek channel from Anzac Highway to the confluence with Keswick Creek, in order to prevent flooding of properties in a 1:100 year ARI event.
Tonkin Consulting was engaged to complete the feasibility and concept design stages of the upgrade and provide assistance during the community consultation phase. Tonkin Consulting has also completed further investigations outside of the original scope as design parameters and project preferences have changed.
With input from subcontractors, the current channel was assessed in relation to a number of issues including heritage, planning, geotechnical properties and biodiversity.
A number of options for the channel upgrade were modelled hydraulically to determine the approximate footprint required to accommodate the design capacity. These options have included lined concrete channels, underground culverts, wide earth channels and stepped rock-lined channels. These options have been assessed in terms of cost, constructability, environmental benefits, community benefits and maintenance.
As an alternative to a main channel upgrade, the option to construct a new culvert through existing roads was also analysed in terms of hydraulic capacity and constructability.
The concept design is currently a work in progress, with anticipated completion in late 2015.