TheState of Colorado's Stream Simulation Model (StateMod) is an integralcomponent of the Colorado Decision Support Systems effort. The StateModmodel is a generic water resource model capable of simulatingstream diversions, instream flow demands, well pumping, reservoir operations andriver flows on a monthly or daily basis for anystream system. Fully developed and calibrated StateMod models represent alldirect flow and storage water rights and reservoir operations inthe following river basins: Upper Colorado River and Gunnison Riverbasins, White River and Yampa River basins, San Juan Riverand Dolores River basins, and Rio Grande basin in Coloradoand the Bear River basin in Wyoming. This paper willprovide engineers, planners, practitioners, [...]