Australian fire danger, 5 Feb 2007, By OzBex, Flickr, Creative Commons
Salisbury, Adelaide: Storm water harvesting secures local jobs
The state of South Australia is experiencing increasing seasonal droughts. The impact of decreasing rainfall has made water supply costly to industrial production. To secure local jobs in the wool industry, which is dependent on a high water supply, the city of Salisbury has invested in cost-effective sustainable water solutions. This case focuses on storm water harvesting and the creation of wetlands as a way to save both local jobs and the marine environment around Salisbury.
Since the beginning of the 1990s, the city of Salisbury - a local government area on the northern fringes of Adelaide, Australia - has been renowned for best practice in water conservation and management. The creation of harvesting facilities to capture storm water and wetlands to cleanse storm water has been Salisbury’s key strategy to provide cheaper water to local industries and protect the urban environment.
In 1999, Australia’s largest wool processing company, G.H. Mitchell & Sons considered outsourcing around 700 local jobs in the wool industry due to high costs of fresh water and sewage disposal. The company’s processing involves the use of 1100 million liters water per year to wash the wool, which in turn produces larges quantities of sludge. A negotiation between city executives and the management of the company resulted in the creation of The Parafield Stormwater Harvesting Facility, which can harvest storm water for industrial production. The cheaper water supply resulting from this facility meant that the local jobs at G.H. Mitchell & Sons were secured.
The Parafield Stormwater Project involves diversion of storm water via a weir in the main drain to a 50 million liter capacity capture basin. From there, it is pumped to a similar capacity holding basin, from where it gravitates to a two hectare cleansing reed bed. The system is designed to hold storm water for around 10 days to ensure optimal treatment efficiency, typically reducing nutrient and pollutant loads by up to 90 per cent. The treated storm water is used for industrial production and irrigation purposes.
A network of 36 wetlands has been constructed to slow the flow of storm water and allow pollution to settle out. Some of Salisbury’s wetlands are designed to process storm water runoff from urban areas in an underground Aquifer Storage and Recovery (ASR) system which secures continuity of supply in dry seasons. While providing a cost-effective sustainable solution to the processing of storm water, the wetlands also play an important role in enhancing the nature and amenity value of the marine environment around Salisbury.
“The major showcase is our network of wetlands that filter and cleanse storm water, in many cases for aquifer storage and recovery (ASR), while enhancing urban landscapes, creating habitat diversity and recreational amenity.” The City of Salisbury (2008)
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