There is a long history of efforts to support water resource decision making with computer simulation/optimization models. Initial efforts often were called decision support systems (DSS) and while this label persists in the literature, a variety of other names for computer-aided decision support systems have emerged (Thiessen, Loucks, and Stedinger 1998). Advances in computational capabilities, user interfaces, and graphical displays have made it possible to rapidly analyze data and display the results for decision participants and decision makers.