A temporary bridge structure, similar to those used by the military and globally for humanitarian emergencies, will be built over Tingalpa Creek as part of the $24 million upgrade of Leslie Harrison Dam.
Seqwater have announced Dam Road, an existing access track off Mount Gravatt–Capalaba Road, will be the main heavy vehicle construction access route during the upgrade of Leslie Harrison Dam.
This follows extensive consultation with local communities, council, contractors and engineers to provide the best solution for construction access.
The community expressed a clear preference for the Dam Road option during consultation on proposed traffic routes earlier this year.
Seqwater Acting Chief Executive Officer Dan Spiller said it was also Seqwater’s preferred option – however Dam Road had significant challenges.
There were concerns that during high tide or flood events heavy vehicles would be unable to cross a typical culvert crossing of Tingalpa Creek below the dam spillway, meaning a secondary access route would also be required to maintain construction access and keep the project on track.
Mr Spiller said Seqwater worked with the construction industry and engineers to identify a solution.
“The community had significant concerns around the environmental, social and safety impacts of the proposed secondary routes,” Mr Spiller said.
“They were also concerned about the cumulative impacts of having to use two routes if the Dam Road creek crossing could not be used all the time.
Local State and council representatives, Don Brown MP and Cr Paul Gleeson challenged the project team to find a solution to construction access that would avoid the need for a second access route.
The solution was found through the installation of a temporary bridge structure, capable of supporting heavy loads of up to 44 tonne in weight.
Redland City Council Mayor Karen Williams said the decision was a positive outcome and would minimize the construction impact on the local community.
“The $24 million upgrade to Leslie Harrison Dam is essential to keep the downstream community safe,” Ms Williams said. ”I am very pleased that Seqwater has been able to respond positively to community feedback”.
The temporary bridge solution will be higher and more resilient than a typical creek crossing for construction access and will reduce the environmental impacts associated with the creek crossing.
Light vehicles will use the existing access via Larbonya Crescent and Willowie Crescent to access the construction site through the Capalaba Water Treatment Plant.
The existing access will also be used as a contingency access route for heavy vehicles in case of emergency.
Caption: An example of a temporary bridge, like the one that will be used to cross Tingalpa Creek.
Seqwater’s Dam Improvement Program:
In 2012-13, Seqwater commissioned an independent assessment of its 26 regulated dams.
This assessment included a review of the condition of our dams and their compliance with current Queensland and Australian guidelines, and has identified a program of work needed to ensure our dams meet these guidelines.
The detailed design for the upgrade of Leslie Harrison Dam has now been completed.
Construction is expected to begin in mid-2018 and will take around 12 months to complete, subject to weather. Features of the upgrade design include:
- Widening and strengthening of the dam wall
- Anchoring the spillway at the crest and the lower end
- Improving resilience to extreme weather events and earthquakes
- Modifying the water intake tower to improve flood immunity.
- The gates will not be returned to the spillway.