Water policy impact assessment – combining modelling techniques in the Great Barrier Reef region

Abstract

The Reef Water Quality Protection Plan (Reef Plan) defined a landmark for policy in the Great Barrier Reef (GBR) region. It identifies actions, mechanisms and partnerships and builds on existing government policies, industry and community initiatives for the purpose of “halting and reversing the decline in water quality entering the Reef within 10 years” through “reducing the load of pollutants from diffuse sources in the water entering the Reef”. A range of different indicators proposed for the nine strategies of the plan define policy goals that require an integrated assessment of the Great Barrier Reef region. In this context and under given uncertainties in regard to policy outcomes, decision support systems can help simulate the impact of potential policy options. Policy options involving water quantity and water quality questions and the underlying context of land use require an understanding of environmental, economic and social consequences. This paper presents an approach developed for the GBR region, which employs a computable general equilibrium (CGE) model and an agent-based model (ABM) for integrated policy impact assessment. This applied modelling approach shows that strengths of different modelling techniques can be combined to support water policy decision making more effectively. This paper is focused on integration in the form of policy process and research response regarding model design on two system scales that provide cross scale decision support.