Ironpot Creek is one of the northernmost waterways of the Bremer River Catchment. The headwaters of the creek begin in the steep, heavily vegetated hills of Pine Mountain and continue down through the suburbs of Blacksoil, Brassall, Karrabin and Wulkuraka before meeting the Bremer River.
The underlying geology of the catchment presents unique challenges for Ironpot Creek, with the upper reaches in and around Walter Zimmerman Park subject to severe erosion. While the origin of this erosion is difficult to pinpoint, it's likely that changes to runoff characteristics following the construction of the Brisbane Valley railway line in the 1890s instigated the erosion of the waterway, resulting in the upper reaches of the creek becoming deeper and steeper with numerous sheer banks.
Clearing historic native vegetation, logging and urbanisation within the catchment have made these issues worse, resulting in ongoing pressures and challenges for the waterway. Fortunately, much of the vegetation holding the banks together sits to the south of the Warrego Highway and remains a valued asset to the city, however, the waterway still needs our help and ongoing management.
Plants and Animals
Invasive weeds such as climbing asparagus fern, cat’s claw creeper and Chinese elm smother and compete with existing vegetation. Council and the community have a role to play in managing these invasive weeds and replacing them with natives to ensure the continuation of healthy riparian vegetation.
Ironpot Creek Improvements
Council and its partners have a number of ongoing initiatives currently in place, and proposed, for the Ironpot catchment. One of the main initiatives was the development of the Ironpot Creek Corridor Plan to identify actions and prioritise investment.
Understanding of the bank instability and erosion issues along Ironpot Creek between Walter Zimmerman Park and Ironpot Creek Reserve was gained and a report prepared to provide a suite of practical management options suitable to be used by landholders wanting to address erosion impacts on their properties, in partnership with their neighbours and Council. The northern section of Ironpot Creek suffers from significant and active stream erosion that, if left unmanaged or mitigation actions uncoordinated, could pose a threat to public safety, private property, infrastructure and the environmental values of the creek and downstream waterways.
The causes of erosion are a result of a combination of historical land clearing, urban and infrastructure development, changed water flow patterns and natural soil characteristics that have increased and accelerated runoff. This in turn has enlarged (both deepened and widened) the creek channel causing an increase in flow volumes and velocities leading to extensive bank erosion, mobilisation of sediment and risking damage to private property.
The Ironpot Creek Drainage and Erosion Management Plan was produced based on the consultation with local residents, a detailed ecological and geomorphologic assessment of the stream, and modelling simulations of stream flow behaviour.
Council and its partners have a number of ongoing initiatives in place and proposed for the Ironpot catchment: