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Blackmans Swamp Creek Stormwater Harvesting Scheme

The Blackmans Swamp Creek Stormwater Harvesting Scheme was the first large scale, indirect-to-potable stormwater harvesting project in NSW, and a pioneer of this approach in Australia. Stage One of this project is capable of providing 900 mega-litres of additional water into the Orange’s raw water supply each year from the city’s stormwater system.

This project evolved from concept to operational reality within 18 months, at a cost of $5 million after extensive consultation with the community and government authorities. Detailed analysis has been undertaken to satisfy concerns about the safety, reliability and capacity of the scheme.

The basic concept of the Blackmans Swamp Creek Stormwater Harvesting Scheme involves capturing a portion of the high flows in Blackmans Swamp Creek during storm events, and transferring these into the nearby Suma Park Dam to add to the city’s bulk water supply.

A number of key elements make this system viable including:

  • the close proximity of Blackmans Swamp Creek to Suma Park Dam;
  • the availability of key existing infrastructure;
  • the very high level of treatment provided by Council’s main water filtration plant at Icely Road, which treats the raw water from Suma Park Dam.

The treatment includes ozone treatment to destroy pathogens and Biologically Activated Carbon Filtration to consume the remnants of the compounds destroyed by the ozone. The regularity of flows in Blackmans Swamp Creek was also a key element. Because of the large impervious areas in the catchment, reliable runoff occurs after every rainfall event.

To assist in the consultation process there has been the development of the Review of Environmental Factors (REF) for this project, which includes a series of operating rules to provide a clear outline of how the project will work. These involve establishing flow trigger points when harvesting can begin, maintaining base flows, and establishing ongoing stakeholder engagement once the project became operational. The council also provides an environmental flow into Summer Hill Creek during the Summer months below the storm water extraction point.

A critical issue throughout the development of this project has been the need to ensure the harvested stormwater meets the appropriate standards of the Australian Drinking Water Guidelines. This is achieved through the creation of multiple barriers within the water supply system to eliminate possible contamination.

 

Under current licencing, Blackmans Swamp Creek scheme can only be used when Suma Park Dam is below 50 per cent of capacity. The council has applied to have this condition modified so water can be extracted when the dam is below 90 per cent of capacity.