CLIENT: Brisbane City Council
INDUSTRY: Local government, NSW
TYPE OF PROJECT: Flood gate restoration
WHEN: (when work commenced and when project was finished, or duration of project)
BRIEF: Residents on Gailey Road, Toowong in Brisbane’s inner west reported unpleasant odours coming from a flood gate outlet into the Brisbane River. Brisbane City Council engaged PMA to develop an innovative solution to clean the flood gate, sump and outlet pipes to restore flow and remove the offending odours.
CHALLENGES: The flood gate outlet directly interfaces with the tidal Brisbane River. Environmental values for water quality released into the Brisbane River were of paramount priority, particularly for turbidity and suspended solids.
PMA needed to find a solution that would enable the work to be done and the problem solved as quickly as possible without letting contaminants enter the Brisbane River water system. This required PMA to design and construct a sediment retention / water settlement basin in the work area to reduce the flow of the water and allow for settlement of sediment.
PMA SOLUTION: To quickly solve this delicate problem, PMA called upon its portable GeoDesign Barrier Dam system to temporarily dam the site and create a work area free from inundation. To maintain the dry working area, pumps were set up to bypass the incoming flow of water around the GeoDesign Barrier Dam downstream and into the Brisbane River.
Using the Barrier Dam system, functional work hours were increased from a three-hour low tide window to a full day, during which debris removal could be performed. The barrier dam prevented incoming tidal water levels of up to 2.2 meters and the project was completed without any instances of environmental non-conformance.
OUTCOME: PMA removed over 200,000L of sediment-laden material from the flood gate and outlet pipes over the eight-day project period. Over that period we moved three or more truckloads of sediment material offsite every day.
Once the work was completed, all flood gates were tested from 0% – 100% operating range and were determined to once again be functioning as intended. PMA recorded and delivered a detailed condition report to Brisbane City Council for the pipe network and floodgate infrastructure.
PMA safely and efficiently delivered this project:
• within a highly urbanised and sensitive environment;
• within the forecast time and cost schedules; and
• without incident or community complaint.
“PMA REMOVED OVER 200,000 LITRES OF SEDIMENT-LADEN MATERIAL OVER THE EIGHT-DAY PROJECT PERIOD.”