Managed aquifer recharge (MAR) is the purposeful recharge of an aquifer under controlled conditions, in order to store the water for later abstraction, or to achieve environmental benefits. It may involve passive treatment of water within the aquifer.
The Department of Water encourages suitable MAR activities that maximise the use of our limited water resources. MAR may not feasible on all sites, due to hydrogeological, environmental, or cost limitations. In some cases, alternative water supply options such as direct use may be preferable.
Under the Rights in Water and Irrigation Act, 1914 recharge and abstraction must not have unacceptable impacts on the groundwater system, the environment or existing groundwater users through changes in water quality or quantity. The potential impacts of recharge and abstraction must be determined as part of the hydrogeological assessment to be undertaken before commencing MAR.
Although the department cannot grant allocation or recharge credits under the existing legislation, it will consider applications for abstraction of recharge water by proponents of MAR schemes favourably through the normal licensing process under the Rights in Water and Irrigation Act, provided that departmental requirements are met.
The assessment of MAR proposals in public drinking water source areas (PDWSAs) will be made on a case-by-case basis. As a guide, MAR proposals within PDWSAs are subject to the department’s groundwater protection strategies, which will depend on a number of water quality factors – such as the quality of the source water, the level of treatment and the intended end use, as well as hydrogeological and environmental risk considerations. The department’s Water quality protection note no.25: Land use compatibility in public drinking water source areas will need to be considered in relation to the infiltration or injection of treated or untreated wastewater into the ground.
MAR proposals involving recycled water may require the application of relevant national guidelines (e.g. Australian guidelines for water recycling – Augmentation of drinking water; Stormwater harvesting and reuse; Managed aquifer recharge modules).
The department will support banking or storage of the recharge water within the aquifer over a short period, provided that the proponent demonstrates that the water will be available for use when required, and that the impacts of abstraction will be acceptable. The period of banking of the recharge water that will be allowed will be determined on a case-by-case basis, based on hydrogeological investigations undertaken by the proponent.
To ensure that abstraction takes place only when recharge water is available, the department will not allow the permanent transfer of water entitlements issued for MAR schemes.
This policy aims to facilitate the development of MAR projects in WA by providing a management framework under the existing legislation. It aims to ensure consistency in the assessment, approval, licensing and monitoring of MAR schemes.
The policy provides specific examples of MAR that are in operation or are proposed in Western Australia, and outlines the key management requirements under this policy.