A software tool, which implements a Decision Support System (DSS) for manag
ement of water reservoirs, is presented. It is designed to be used both at
the planning level, by water agencies, to generate management policies and
release plans over various time horizons, and at the management level, by t
he decision makers, to take daily release decisions, also using the real-ti
me information provided by a telemetering network. The DSS algorithm presen
ts multiple choices to the decision makers, helping them in assessing their
impact, thus integrating, not substituting, human intelligence. The DSS ar
chitecture relies on a Model Management System (MMS) to allow a rapid proto
typing of various modelling situations, both at the planning level and at t
he management level, while the graphical user interface is aimed at enforci
ng this structure.