Australia's water policy and infrastructure investment decisions require high-resolution climate information taking into account both past and future variability. Currently information exists for limited geographical regions such as single catchments, urban regions or states from multiple regional downscaling efforts and using different methods to interpret this data for hydrological impacts. These regional downscaling and hydrological impact data collections are either not application-ready or tailored for specific purposes only, which poses additional barriers to their use across the water and other sectors. Agreed and consistent approaches across impacts at the national scale are yet to be developed. However, an accessible and consistent set of climate projections for water will help ensure that climate change risks are properly factored into decision-making.

The Bureau of Meteorology is developing a seamless national landscape water service, combining historical data on water availability with forecast products, as well as hydrological impact projections. This system uses a consistent methodology based upon the AWRA-L hydrological model across all time scales. From an end-users perspective the service will facilitate understanding of both past and future variability across multiple timescales of interest, and the associated impacts under a changing climate.

For services to meet decision-maker’s needs they must be designed in consultation with end users. An extensive user centred design (UCD) process underpins the scope and nature of the new service. This presentation will share insights on the UCD outcomes including user-defined data requirements, especially with regards to past and future variability. End users also clearly expressed the need for guidance material and information about confidence and uncertainty to accompany and contextualise projections information. We will describe the proposed confidence and uncertainty assessment process to be undertaken as part of the hydrological projections service, which will underpin development of guidance material for decision makers to assist navigation of multiple datasets.