Seasonal streamflow forecasts to improve management of water resources: 5. Major issues and future directions in Australia

The paper reports on major issues encountered in two related projects aimed at improved management of water resources through use of seasonal forecasting of streamflow, and discusses future directions to improve water resource management in Australia. The national Rainman Streamflow Project set out to aid water management in Australia by: (1) working with primary producers and water agencies to assess the value of streamflow/runoff forecasts, (2) developing methods to forecast streamflows and runoff, (3) assembling a national streamflow and runoff data set for use in the AUSTRALIAN RAINMAN computer software package, and (4) building a communications program to facilitate adoption of improved practices. Further information about these tasks may be found in the associated papers at this conference. A related Murray Darling Basin Project examined in detail the economic benefits of using seasonal forecasting of streamflow for irrigated cotton production in the impacted Border Rivers catchment of Queensland / New South Wales. The Streamflow Project showed that empowering people to analyse streamflow and runoff data using AUSTRALIAN RAINMAN was an effective way to improve their water management. However, long-term reliable records of streamflow with local relevance were needed for seasonal forecasting. Data shortages could be largely overcome by use of models to extend short records and to separate out climatic effects from human impacts, provided the modelling results were made available by water agencies. Forecasting often involved integrating information about rainfall, streamflow and climate. There was considerable dependency at present on workshops to raise awareness, provide a basic background in climatology, and build self-reliance with computer software. There were major synergies when irrigators, water agencies and scientists worked together, for example in documenting potential financial benefits. Seasonal climate forecasting has a lot to offer water users (including irrigators, water agencies, environmentalists and government). This paper considers that the main issues of seasonal climate forecasting to improve management of water resources are: obtaining locally relevant data including modelled data from impacted catchments; extending records to the limit of rainfall by modelling; implementing and improving new forecasting tools; integrating forecasts with local rules to assess water allocation; forecasting of overland flows; assessing the value of forecasting (economic, environmental, managerial [demand/supply], water trading); balancing needs of different water use groups where there is potential conflict; transparency of forecast methods; and communication and education about these issues. An holistic approach to land and water issues involving climate variability is essential for future progress.