When setting up and operating any stormwater harvesting and reuse project, including a managed aquifer recharge (MAR) scheme, you must abide by the regulations. For example, there are rules about the quantity and quality of water that you can store for later use. The regulations are in place to protect the state’s environmental assets, including rivers, groundwater systems and other water resources.
MAR schemes in South Australia are regulated under the following acts:
- The Natural Resources Management Act 2004 has specific provisions that primarily deal with water quantity issues, including prescription, control of use, development of catchment and water allocation plans and environmental flows.
- The Environment Protection Act 1993 requires that you obtain a works or development approval before you build a MAR scheme. It also requires that you gain an environmental authorisation before carrying out activities of ‘environmental significance’, including the discharge of waters to aquifers. All MAR schemes, regardless of their size or geographical location, are required to adhere to the requirements this Act and the Environment Protection (Water Quality) Policy 2003 and other policies under it.
- The Public and Environmental Health Act 1987 contains provisions for the protection of public health, including sanitation and water supply. Under this Act, the Public and Environmental Health (Wastewater Systems) Regulations 2010 (Wastewater Systems Regulations) provide details about the management of wastewater systems, including the reuse of the wastewater.
- The Development Act 1993 provides for the consideration of any scheme that is deemed to be a ‘development’. If your MAR scheme proposal is deemed to be a development, you may need to submit a development application form to the relevant planning authority. Contact your local council in the first instance for advice.
Note that if you are not draining or injecting the water for the benefit of the aquifer, or extracting water from it at a later date, the activity is classified as a method of disposal rather than a MAR.
Who oversees the regulations?
The department and the Natural Resources Management boards are responsible for managing the quantity of water in relation to ensuring minimal negative impacts on natural water resources.
The Environment Protection Authority SA is the main regulator of the quality of water drained or injected into an aquifer and of contaminated sites.
SA Health manages the human health aspects of the use of recycled water, such as stormwater and treated wastewater after the water is extracted.
How do MAR schemes help meet water security goals?
A number of key targets within our state’s long term Water for Good plan directly relate to stormwater harvesting and reuse schemes, such as ‘supply 20 gigalitres per year of stormwater by 2013’, and ‘60 gigalitres per year by 2050’ for Greater Adelaide.
Another example is the key action by 2025 that ‘groundwater desalination plants or other economically viable innovative supply options will provide water for regional townships where water quality… has been identified as an issue’. MAR schemes fall into the ‘innovative supply option’ category.
In South Australia, MAR schemes have been underway since the 1990s, mainly as a part of stormwater harvesting and reuse schemes. Across the Adelaide Plains are several areas where suitable aquifers exist to recharge and store water in viable amounts.
What are the benefits to the environment?
Stormwater and wastewater contain substances such as sediments, metals, pesticides, herbicides, nutrients and organic compounds which can pose adverse risks to human health and the environment.
However, with good-quality treatment systems, stormwater harvesting and reuse schemes can benefit groundwater resources (through replenishment of declining aquifer groundwater levels) and other environments such as urban streams and the Gulf St Vincent.
If the recycled water is not treated to an appropriate level, drainage or injection of this water into an aquifer can cause a risk to human health and the environment, including rendering an aquifer unsuitable for certain beneficial uses (e.g. potable or irrigation).
Drainage or injection and subsequent extraction of water can also cause hydrogeological impacts, such as movement of existing contaminated or saline groundwater plumes into areas of better water quality, and excessive pressurisation. This is why MAR schemes in South Australia are regulated to provide confidence that they are viable and sustainable.