Having focused on information management and analysis so far in this review, we should emphasize that friendly user interfaces are likely to have the greatest impact on whether or not a particular DSS is actually used by decision makers. Increasingly available graphics-based toolkits, graphics libraries, and user interface builders can greatly facilitate the development of friendly interfaces by eliminating the need to program them from scratch. Alternatively, designers can use tools such as mapping or drawing programs ( Chen [1991]). However, the lack of discussion of user interfaces in the literature suggests that water resources researchers and practitioners have not yet become well acquainted with these tools. For instance, Bender et al. [1993] discussed the development of a graphical user-interface for the validation and verification of an expert system for reservoir management. They concluded that a combination of graphical techniques and methodologies could be expected to be valuable for expert system verification but added, ``The use of advanced computing tools such as interactive computer graphics is difficult for engineers to implement... [and] generally more suited to computer programmers.''
A different approach has been taken by researchers at the International Institute for Applied Systems Analysis. The Advanced Computer Applications project has built several water resources DSSs with highly sophisticated graphical user interfaces. Founding their work on a common system architecture, they have been able to develop highly interactive, ``seamless'' systems with embedded pre- and post- processors. This architecture has allowed high efficiency and performance (speed), but little modularity, making it difficult to apply the systems to slightly different problem domains. However, the interdisciplinary nature of the project and the long-term commitment of resources are perhaps uncommon in water resources research and planning (i.e., not everyone could or should take this approach) [ Fedra, 1993b].
Research in the last four years has also extended beyond traditional graphical user interfaces. Câmara [1991] discussed the use of multidimensional modeling for water resources management. Multidimensional models included numerical, linguistic, and pictorial entities and relationships, which were deemed appropriate for spatially-related problems such as water quality modeling and ecological impact assessment. Loucks [1993] discussed interactive multi-media (video and sound) links to GIS and simulation models. On-line help from video files, model text prompts which can be heard as well as read, and the animation of simulation output are a few of the not-so-futuristic ideas offered for enhancing DSSs through multi-media.