Understanding the relationship between land use and water quality
To provide an evidence base for consideration of how water quality objectives, which should include interactions between groundwater and stormwater systems, could be delivered as part of the land use planning and development approvals system in WA. It includes a review of existing national and international examples of objectives and targets for improved water quality. This in turn will be used to propose a number of implementation options for further consideration, with particular reference to the Peel-Harvey Catchment.
Completed 2018. The paper is a starting point for discussion. It presents a number of options which should be further investigated by State and local government together with industry as part of a collaborative process to establish numerical targets and an implementation mechanism which incorporates monitoring and review.
In Western Australia, State Planning Policy 2.9: Water Resources requires consideration of the principles of water sensitive urban design as part of the planning and development approvals process, as outlined in Better Urban Water Management (WAPC, 2008). While water quality targets are identified as an important matter in these policies, application of such policy to planning decisions remains discretionary and this can lead to inconsistent outcomes.
Water quality objectives and targets can play a key role in the implementation of water sensitive urban design (WSUD) if supported by detailed implementation guidelines and a clear legislative requirement to achieve targets through WSUD (Choi & McIlrath, 2017). A range of catchment scale numeric water quality targets have been developed for selected catchments in WA including the Peel-Harvey Estuary; however, there is a need to link these targets with lot-scale targets, so they can be implemented at a development scale. In Victoria and Queensland, planning policy requires development to be designed to meet best practice performance standards (water quality targets). While it is considered that this policy has been instrumental in supporting WSUD approaches across growth corridors, it is considered that the policy is not delivering the kind of environmental outcomes needed to materially improve waterway health (Choi & McIlrath, 2017).
The international examples also demonstrate the importance of having clear, measurable targets within a broader framework which encompasses the complete range of values associated with a system including social and economic values together with ecological health.
In considering options for establishing water quality targets as part of the land use planning system in WA, it is critical that they strengthen and complement existing requirements. Industry should be actively engaged in the discussion of technical and operational options including links to receiving environment; outcome, design or performance based targets; measuring compliance; and industry and regulatory capacity. Consideration should also be given to linkages with the achievement of broader WSUD objectives.
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