Barron Catchment Care recently was successful in obtaining funding through the Community Grants Program for the Wet Tropics to undertake a scoping study to identify areas where detention and streamline repair would be most effective in the Upper Spring Creek sub-catchment.
This scoping study project is aimed at identifying opportunities in the upper section of the Spring Creek catchment to reduce peak flows, trap sediments and lower the impacts of runoff downstream. The proposed works identified by the study will also address localised flooding and sediment related issues that occur within the upper section of the catchment, and improve the amount of water that is infiltrated back into ground water reservoirs.
The Spring Creek Catchment emanates from Bones Knob Hill which is just west of the township of Tolga on the Atherton Tablelands. The catchment flows into the Barron River north of Tolga and hence on to discharge to the Great Barrier Reef near Cairns. The catchment can be divided into two sections with a steeper upper section west of the Kennedy Highway and a section of lesser grade east of and below the highway. There have been significant erosion and flood related issues along sections of the creek, particularly in the lower section.
The scoping study is the first part of a staged approach where sites are identified and assessed followed by detailed design of specific sites and then followed by on ground construction. Previous projects undertaken by BCC have successfully used this approach which is a project strategy aimed at ensuring works are undertaken at the best possible sites and that the works fits into an overarching catchment based strategy. BCC has already undertaken several smaller scale site-specific analysis of the Spring Creek catchment at 2 locations – the Gannon and Weis/Austin project sites. This project will incorporate these studies and complete the analysis of the upper Spring Creek catchment above the Kennedy Highway.
The project will include a hydrologic analysis of the upper catchment based on available height and streamline data and will identify areas where remediation works could be effectively constructed. The sites will include those appropriate for detention and also streamline repair. A large portion of the upper catchment streamline is degraded through a building up of eroded topsoil and the removal of protective vegetation. Streamline repair would include reinstatement of stream capacity, an increase in in-stream detention, which reduces velocities and downstream rates of discharge, and long term protection through appropriate revegetation.
The area of the study is renowned for seasonal spring storms with a more consistent winter rainfall pattern. Most of the hydraulic and sediment transfer issues affecting downstream are associated with severe storm patterns through tropical storms that develop during late spring and early summer. The hydrologic analysis will look at the effect of these storms separately to the normal assessment using rainfall derived from long term averages that include the winter data. Potential sites will be assessed for their capacity to improve these downstream effects, particularly during storm events.
The final deliverables of the project include a report on the catchment hydrological dynamics, identified mitigation sites and options, and an analysis of the effectiveness of these options in repairing the catchment. This will facilitate consideration and selection of the identified options by BCC and other stakeholders prior to progression onto the more detailed stages.
Identifying stormwater mitigation sites in Upper Spring Creek catchment, near Tolga.