Translations:Begriffsdefinitionen/3/en

The term water resources system includes all water-related transport and storage processes within a limited area, whereas it is irrelevant if it is a real-world system, or it represents a potential future or a planning state. The water-related processes are integrated into a model as individual components or elements. The simulation of water resources systems requires an abstract representation of the real-world processes as mathematical equations to carry out the calculation of hydrological and hydraulic processes. In other words, the system should perform the abstraction and mapping of the spatial and temporal distribution of water. To completely determine a water resources system, the definition of system boundaries is necessary. These boundaries are not only of spatial nature due to catchment area boundaries, but they are also a distinction between system loads and system results. The system loads - water supply and water demand - affect the system from the outside and trigger processes within the system, i.e. they do not directly belong to the system itself. It is assumed that there is no feedback between the system and system load. However, this assumption becomes less and less valid the more a water management system interferes with the water balance. Consequently, a water resources system is the sum of components or elements, which mathematically represent the water-related processes. The representation of the flow relationships between the elements is also part of a water resources system. Depending on the respective objective, a multitude of spatial resolutions can be achieved. Considering all processes, taking place in water management systems, is neither meaningful nor possible. Generally, it is advised to record all relevant processes and to represent them as accurately as necessary. Sometimes, this requires the abstraction and combination of different transport and storage processes. Integrating several processes into the system as one combined element results in a representation of reality through individual calculation units. These units will be called system elements in the following. A system element always delivers the same results facing the same conditions. System elements undergo a classification, which will be explained later on. The size and structure of a system element are determined either by geography, water management processes, or by both. For example, a reservoir is delimited by its storage space and the structure itself, with all comprised processes influencing each other. For this reason, operating facilities such as spillways, bottom discharge, and operating discharge are part of the system element reservoir. Geography and water resource processes are thus responsible for the design of the system element reservoir.