Target 74 of South Australia’s Strategic Plan aimss to harvest up to 50,000 megalitres (ML) of treated wastewater per annum by 2025. In 2017 recycled wastewater capacity was estimated at 74,000 ML/yr. The Northern Adelaide Irrigation Scheme (NAIS) will create a new irrigation area using recycled water from the Bolivar Wastewater Treatment Plant.
Construction of Stage 1 of NAIS, which will deliver up to 12 GL of reclaimed water suitable for commercial food production, is expected to start in early 2018 with the intention of recycled water flowing to growers from 2019.
Target 73 of South Australia’s Strategic Plan aspires to harvest up to 35,000 megalitres of stormwater per annum by 2025. There are 58 harvesting schemes that use aquifers for water storage across SA that are capable of harvesting, treating and storing around 23,000 megalitres of stormwater. Few stormwater harvesting and reuse projects are currently in progress as Federal and State government funding support has largely ceased.
Managed aquifer recharge
Adelaide is the global leader in managed aquifer recharge (MAR) development. MAR has developed rapidly during the past 30 years from small-scale passive-filtered gravity-fed demonstration sites to large-scale integrated urban developments with advanced filtration and high-pressure injection wells. During that time there has been significant investment by governments and the industry to develop the technology and increase its use.
Whilst the first trials of MAR in Adelaide can be traced back to 1951, MAR in Adelaide has had a short history with the first scheme established in 1989. From that time the number MAR schemes increased rapidly as industry capability developed and with improved understanding and acceptance from communities and the government.
During the 1990s several schemes successfully demonstrated the viability of MAR for the city’s climate, hydrogeology and water-demand profile. The number of MAR schemes operating in Adelaide expanded rapidly after 2000 in response to the Millennium drought and the government’s policy response to this. In addition to the new schemes, hundreds of millions of dollars were invested in non-potable water distribution mains to transport water from MAR schemes and wastewater treatment plants to demand nodes. These distribution mains allow MAR schemes to supply water to school ovals, public reserves, industry, private residential areas within the metropolitan area and large horticultural and viticultural areas to the north and south of the city.
Overall, the survey and literature review identified that there have been 58 MAR sites constructed during the past 30 years, as well as 700 kilometres (km) of non-potable water mains.