Water is a serious problem here in South Australia but one local council is doing something about it. In fact, they are leading the world in storm water treatment and re-use. Many years ago they began to use some dry and dusty land as a series of holding ponds for storm water runoff. It was then a rough and ready arrangement which has now grown to be a showcase for water conservation.
Stormwater is water that runs off surfaces such as roofs, roads, footpaths and driveways when it rains. Much of this water flows into stormwater drains and then into creeks and rivers, eventually making its way into the sea. About 160,000 million litres of polluted stormwater was being released into Gulf St Vincent each year, much of it into the Barker Inlet.
In the 1990's the City of Salisbury defined a vision that it would seek to eliminate the flow of polluted water into the marine environment of the Barker Inlet of Gulf St. Vincent. The Barker Inlet is a delicate marine environment of mangroves and sea grass meadows serving as a nursery for a majority of the State's fishing industry. However, years of neglect and polluted inflows have reduced the Barker Inlet to a delicate state.
The creation of wetlands to cleanse stormwater was Salisbury's key strategy to help the ecological rehabilitation of the Barker Inlet while providing cheaper water to local industry and other users. Nutrient and pollutant loads are typically reduced by up to 90 per cent and the treated water salinity is less than 250 mg/L. The system is designed to hold stormwater for around 10 days to ensure optimal treatment efficiency.
Stormwater is treated and harnessed in a series of more than 30 wetlands along urban stormwater paths to slow the flow and allow pollution to settle out. The wetlands cover an area of 260 hectares enhancing the landscape and creating habitat diversity.
All the wetland plants are propagated at the Council's nursery and they play an important role in the treatment of polluted stormwater. The nursery has developed a high level of expertise in propagating various wetland species, and it sells wetland plants to users all around Australia.
As drought hit our state, demands for water also increased and the council researched storing cleaned stormwater underground in aquifers for re-use later. Aquifer Storage and Recovery (ASR) is the process of injecting water into a suitable underground aquifer for storage and later reuse, and it can be a means of artificially recharging depleted underground water supplies.
ASR is a modification of the natural system that has been occurring for millions of years. Natural recharge occurs by filtration of rainwater through the soil profile, past the vegetation root zone and down to permeable rocks known as aquifers.Aquifers can store large quantities of water without losses from evaporation and with reduced risk of contamination, both of which are problems associated with surface water storage areas such as reservoir.
In March there was an excellent talk given at the Rare Fruits Meeting, by Colin Pitman, the Director of Projects at the Salisbury Council. He explained that they have now mapped the whole of Adelaide and made plans for supplying enough water to Adelaide to make it independent of the River Murray. The wetlands and aquifer system is suited to Adelaide's winter rainfall and underground geology and can hold the best solution for all our water needs, relatively cheaply and will return a profit, as it does for the Salisbury Council. I would be very happy to dispense with our current, antiquated water authority and buy my water directly from such a system as this.
I have a CD of the talk which is inspiring and full of information. If anyone would like to borrow it please email me.
Last week I went for a walk at what is now called the Greenfields Wetlands and found it to be not only useful but full of wildlife and photo opportunities! It is amazing to think that what once a dry, barren and awful part of the outskirts of Adelaide, in a triangle between 2 major roads, is now home to thousands of birds, frogs, lizards and insects. It is worth the drive.... go and look for yourself.
|There are many bridges through the Melaleucas|
|You can see the oxygenating of the water happening here as nature cleans the water|
|If I had binoculars, I could see my house on the top of one of those hills, from here.|