System harmonisation framework for water resources planning in peri-urban catchments

Sustainable water resources management has become a pressing issue in Australia. In this study, water redistribution will be assessed based on the "System Harmonisation" framework, addressing social, hydrological, and economic impacts arising from alternative planning and management decisions in Western Sydney's South Creek Catchment. The main aim of this research is to develop and validate a dynamic tool for integrated water resources planning and strategy development in complex landscapes adaptable across Australia and beyond. Specific to this environmentally degraded catchment, population and industrial growth is expected, resulting in an increase in demand for water in the next twenty five years. Concerns relate to the appropriate, most effective allocation of scarce water resources, especially to maintain agricultural productivity and environmental requirements. Within the System Harmonization framework, A Block-wise TOPMODEL with Muskingum-Cunge flow routing method (BTOPMC) hydrologic model was used to synthesise catchment supply and stream flows, a network resource allocation model Resource Allocation Model (REALM) was used to analyse level of water security under different demand regimes with current and future scenarios. And lastly, allocation modelling output underwent Social Cost-Benefit Analyses, using inductively estimated values for water used in different sectors for various pursuits, whereby multiple scenarios could be compared against one another. At present, there are numerous urban development plans for the catchment; population is expected to increase from about 390,000 to 1 Million by 2030. In addition, potential climatic changes in the catchment can be expected, whereby hydrology for the system was modelled using CSIRO climate change prediction models output for the region, where overall supply in the system was found to decrease due to decrease in precipitation and increase in evapotranspiration. Scenario development for anticipated future changes in demand and available supply within the catchment is well underway through extensive stakeholder consultation, with consideration being given to projected changes. The hydrological and economic impacts of these processes were assessed and preliminary results are presented in this paper. With expected high stresses relating to water shortage, it was found that assessing effects of water redistribution from a multi-disciplinary perspective could be extremely useful to policymakers in the South Creek Catchment. System Harmonisation has proven capable of critiquing potential scenarios in terms of quantifying economic potential given the resource allocation of a particular scheme.