ArcGRM: interactive simulation system for water resources planning and management in river basins

Water resources planning and management are in general stochastic problems. Because of the uncertain hydro-meteorological processes and the resulting spatial-temporal distribution of runoff generation, the runoff process over a long period should be treated as a random process. The user demands, on the other hand, are deterministic in time and space from the planner's point of view. Based on that, the stochastic management models of the GRM type divide the stochastic management problem into three parts: stochastic simulation of meteorological and hydrological processes, deterministic simulation of the processes of water use and finally recording of relevant system states. The model system ArcGRM and its application for the river basin Spree with extensive lignite mining impacts are described. An outlook on further developments is given.