Council invests heavily in drainage improvement works to reduce the impact of flooding caused by king tides and heavy rainfall.
Over the last five years, Council has invested nearly $25 million on drainage works around various suburbs to upgrade pipes and concrete drains, install new culverts and increase the capacity of existing drains.
CBD flood mitigation scheme
Featuring a $9 million tidal outlet and underground pump station in Lake Street, the scheme can move four tonnes of stormwater per second into Trinity Inlet. Designed to cope with 1-in-100 year flooding events, the project has significantly reduced the impact of king tides and intense rainfall on businesses and properties in the Cairns CBD.
Lake Placid flood mitigation scheme
This $1.4 million project delivered a series of levee walls and flood gates to protect more than 400 homes, businesses and infrastructure in suburbs along the Barron River delta.
Three sets of tide gates are installed at the sea-facing end of waterways in central Cairns. The gates are lowered into the waterway when very high tides (king tides) are forecast to stop saltwater from flooding low-lying areas of land. When stormwater levels are higher than tidal water levels, the tide gates open wider to allow stormwater to flow to the ocean.
Backflow prevention devices
Backflow prevention devices have been installed in various locations around the Cairns locality as another form of tide control to prevent the re-entry of tidal waters into the stormwater network. Council has various types in service including a memory rubber type which opens with minimal water pressure behind it to allow free drainage and any pressure on the front seals the opening. These devices can still drain even with sand or debris built up at the front of the device.