Implementation of a water allocation decision support system in the Namoi and Gwydir valleys

Management of water resources often involves significant negotiation with regard to complex social, economic and environmental trade-offs likely to result from changes in policy or access. In NSW, changes to water allocations and access, through the design and implementation of Water Sharing Plans, involved negotiation between stakeholders representing many different interests and concerns. A key gap identified by many stakeholders involved in these negotiations was easy access to integrated, scientifically sound and generally agreed upon information on the socioeconomic trade-offs likely to result from changes in access, allocation and pricing. In addition, estimates of impacts on the flow regime and on river health are also required. This paper describes the Water Allocation Decision Support System (WAdss) developed to consider these types of trade-offs resulting from changes to access and allocation across the three water systems (unregulated, regulated and groundwater), and its implementation to two NSW catchments, the Gwydir and Namoi catchments. The WAdss has been developed in a modeling platform, ICMS, developed by CSIRO Land and Water. This platform allows for development of a model and data base which can be overlaid by custom built Graphical User Interfaces (GUI). This approach allows for rapid development and testing of both models and interfaces. Model development in ICMS uses a semi-object oriented paradigm, with classes of objects being defined which can be associated with numerous procedural models. An instance of a class (or object) is then associated with a specific model code and a set of data. The WAdss consists of: a generic DSS structure and concept, which is encapsulated in a set of classes and a generic interface, consisting of the code and standard content files; and, specific applications of this generic structure and concept. These applications are defined by an object configuration, a data base and object specific model choice, and a set of application specific files which tailor the interface to the catchment. In this way the DSS concept, structure and interface is able to be reapplied to new catchment situations. The WAdss has been developed to be used in a workshop situation, allowing for analysis of a library of pre-run scenarios, sharing of scenarios between users, and creation of new scenarios live in meetings and workshops. It also allows for reports to be generated from scenarios. Development of the WAdss has involved substantial stakeholder involvement. This has been aimed at: giving stakeholders a greater sense of ownership of the models, results and WAdss by incorporating their comments and ideas into the system; obtaining information and data necessary for groundtruthing or calibrating the models in the system; and, increasing the awareness of stakeholder groups of the existence of WAdss, its potential uses and limitations. Overall the development process of the WAdss has been successful, given the maintained engagement of stakeholders in its development and support for its continued use and development. However, the WAdss is now moving into an adoption, extension and reapplication phase and success in this phase will depend on the maintained engagement of stakeholders, and the enthusiasm and input of researchers or other champions within Agencies or Management Authorities continues. Without this, the investment placed in any DSS can only lead to one-off solutions.