Protecting the CBD
The central business district of Cairns is located close to the sea and is relatively low and flat, with parts of the southern CBD – featuring extensive tourist and residential development – actually below high tide level. Cairns is also one of the wettest parts of Australia, with rainfall intensities delivering over 150mm per hour during 20 to 30 minute storms.
With these factors combined, severe flooding in the southern CBD has been a frequent occurrence in the city’s history, made even worse when storms coincide with high tides or storm surges associated with cyclones.
To safeguard private properties, businesses and Council infrastructure against such flooding, Council implemented innovation flood mitigation works in the low lying southern CBD. The $9 million dollar CBD South Flood Mitigation Scheme (completed in 2009) saw construction of an underground pump station capable of moving a massive five cubic metres of stormwater per second into the ocean.
With a pumping capacity of 4,800 litres per second, the four specialised pumping units were the first of their type in the region.
Detailed modelling of the drainage solution in 2006 required the coupling of two stormwater drainage programs, and was the first urban application of this coupling undertaken in Australia.
