**6. Comparative summary of modeling capabilities**

ResSim, MODSIM, WRAP, RiverWare, and other similar models provide flexible capabilities for analyzing multiple-purpose river/reservoir system operations. The models are water accounting systems that compute reservoir storages and releases and stream flows for each time step of a specified hydrologic period-of-analysis for a particular scenario of water resources development, management, allocation, and use. Though fundamentally similar, ResSim, MODSIM, WRAP, and RiverWare differ significantly in their organizational structure, computational algorithms, user interfaces, and data management mechanisms. The alternative modeling systems provide general frameworks for constructing and applying models for specific systems of reservoirs and river reaches. Each of the generalized modeling systems is based upon its own set of modeling strategies and methods and has its own terminology or modeling language.
