As eWater is a major provider of modelling products, this family of guidelines help us meet our aim to foster a best practice approach to the use of these products. In addition, the guidelines addresses a need, identified by many water management agencies across Australia, for model application guidelines. This need has arisen as a result of growing expectations of stakeholders—the National Water Initiative (NWI) and the Council of Australian Governments (COAG)—that there should be a consistent and transparent approach to applying models used to support water management decisions across the country to: improve modelling practice provide quality assurance, including evaluation of uncertainty remove inconsistencies between model applications, including in adjoining catchments where the same model code is used in both, and in situations such as managed river systems that interact with one another improve decision making, including improving the use of science to improve the quality and robustness of decisions made and outcomes improve communication with end-users of model results: water managers, decision makers and the wider community provide a process that is transparent, robust and repeatable.

Water modellers and managers concerned with model application

• improve modelling practice
• provide quality assurance, including evaluation of uncertainty
• remove inconsistencies between model applications, including in adjoining catchments where the same model code is used in both, and in situations such as managed river systems that interact with one another
• improve decision making, including improving the use of science to improve the quality and robustness of decisions made and outcomes
• improve communication with end-users of model results: water managers, decision makers and the wider community
• provide a process that is transparent, robust and repeatable.

These guidelines provide an integrated approach that enables interactions and feedbacks between all domains revevant to water management (eg hydrological, ecological, engineering, social, economic and environmental) to be considered. It provides for outputs of analyses in these domains to feed into multi-objective decision analysis, which links outputs with views and preferences of multiple stakeholders and enables decisiona to be made with the aim of satisfying the objectives of all sectors. In addition, the procedure in these guidelines is intended to be flexible enough to accommodate variations in the meaning of 'Best Practice Modelling' and also allow for continuous improvement as the state of knowledge and technology in the modelling field develops.