Opportunities to protect and improve waterways in urban areas are often constrained by space and water demand to adequately deal with the common problem of too much stormwater in wet weather and reduced flows in dry weather. These impacts are predicted to become more pronounced in many parts of Australia under climate change. The development of real-time monitoring and control technology creates the potential for hybrid centralised-decentralised urban water networks as a way of addressing these challenges. The Monbulk Creek Smart Water Network in the south eastern suburbs of Melbourne, will integrate up to 300 household and council rainwater tanks with three large urban lakes, jointly operated by Melbourne Water and South East Water. As well as providing non-potable water supply and reducing flood risk by drawing down storages prior to rain events, the network provides environmental flows to support a threatened platypus and waterway health more broadly.
Household rainwater tanks are connected to indoor (e.g. toilet flushing, clothes washing & laundry) and outdoor uses, as well as a connection to the stormwater network to deliver environmental flows and pre-storm releases. The large water storages will provide much of the environmental water releases. Using a control algorithm, water release requests are made on a daily basis based on water levels in the rainwater tanks and urban lakes, as well as current flows within Monbulk Creek and 7-day rainfall forecasts. The performance of the Monbulk Creek Smart Water Network is being evaluated by measuring changes in stream flows and associated predictions of modelled instream habitat, household water use practices, platypus foraging behaviour and aquatic macroinvertebrate abundance and diversity. The network provides a proof-of-concept and future work will investigate the potential to use economic incentives for household contributions to environmental flows.