Sustainability Report 2006/07Case study: Managing peak flows
The $650 million Northern Sewerage Project will bring significant benefits for Merri and Moonee Ponds Creeks, protecting them from sewage spills during heavy rain. At the other end, Melbourne Water is designing an upgrade to the Western Treatment Plant at Werribee to ensure the plant can cater for increased peak flows, especially in wet weather, when the Northern Sewerage Project comes on line.
Melbourne Water planners are evaluating three options to enable the plant to deal with greater volumes of sewage as a result of the project.
Planned works will increase the capacity of the southern carrier, one of three channels that distribute sewage to treatment lagoons at the plant. The options are to raise the height of the channel walls, build a duplicate channel or install a new pipeline.
Once this extra capacity has been built, the two other channels (the eastern carrier and the western carrier) will be decommissioned.
This will deliver social and environmental benefits. The eastern carrier is an open channel and can be a significant source of odour near the plant’s eastern boundary and the future River Park (formerly Werribee Field) residential development. The western carrier is susceptible to flooding in extreme rainfall events.
The wet weather upgrade will mean the plant can continue to meet, under increased flow conditions, requirements of the State Environment Protection Policy that it has the capacity to contain a one in five-year rainfall event. The upgrade works are expected to be completed by the end of 2010.