Translations:Begriffsdefinitionen/3/en

Under the term water resources system all water-related transport and storage processes within a delimited area are summarized, whereas it is irrelevant if the system actually exists, or represents a future or possible planning state. The water-related processes are summarized in individual components or elements.The simulation of such a system requires the transformation of the actual running processes (reality) into mathematical equations for the calculation of the hydrological and hydraulic processes. In other words, it is the abstraction and mapping of the spatial and temporal distribution of water.

For the complete coverage of a water resources system, the definition of the boundaries is necessary. These boundaries are, on the one hand, of a purely spatial nature due to catchment area boundaries. On the other hand, a distinction between system load and system results. The system loads - water supply and water demand - affect the system from the outside and trigger processes in the system, i.e. they do not directly belong to the system itself. It is assumed that there is no feedback between system and system load. However, this assumption becomes less and less valid the more the water management system interferes with the water balance.

Consequently, a system is the sum of components or elements which in turn 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, different spatial resolutions result. A consideration of all processes taking place in water management systems is neither meaningful nor possible. The principle is to record all relevant processes and to represent them as accurately as necessary. This requires the abstraction and combination of different transport and storage processes. This integration of several processes results in a representation of reality by means of individual calculation units. These units will be called system elements in the following. A system element always delivers the same results under the same conditions. A classification of the elements is done later. The size and structure of a system element is determined by geography, by water management processes or by both factors together. For example, a dam - storage basin - is delimited by the storage space and the structure itself, because all processes taking place in it influence each other. For this reason, operating facilities such as spillways, bottom and operating drains are part of the system element of a dam. Geography and water management processes are thus responsible for the design of the system element dam.