Renewing a sewerage system is a huge undertaking and Launceston’s sewerage system, begun in the 1860s, is among the oldest systems in Australia. Group Manager Infrastructure, Geoff Brayford, said over time the system proved unable to cope with the flows generated by heavy rainfall, city growth and development in the catchments.
“It was now time for an innovative and creative solution – the Margaret Street Detention Basin,” he said. “Detention basins may not be considered particularly innovative or creative as they have been used for decades, but never in a combined sewerage system. This presented us with a unique challenge never faced by any other drainage or sewerage authority in Australia.”
The final design created two storage volumes, one of 7,000 cubic metres of covered storage to deal with more polluted flows and one of 23,000 cubic metres of open storage to deal with less frequent storm events. Flows between the two were clarified and screened and all floating materials intercepted.
Apart from the financial benefits from reduced flood damage to property, delivering a rate of return of seven per cent per annum on the overall investment, and a number of other benefits were also realised. Geoff Brayford said river water quality was improved as the more polluted flows could be retained for slow delivery to the treatment plants.
For more information contact Geoff Brayford, on (03) 6323 3220 or geoff.brayford@launceston.tas.gov.au
