Translations:Begriffsdefinitionen/5/en

All values necessary to describe the system elements and their flow relations are summarized under the term system data (arrangement of the system elements, parameters, and characteristics). The system loads generate - using the system data - at the respective elements certain system states and resulting reactions. System states describe momentary conditions within the system and are variable over time. States and responses are assigned to individual system elements. The terms parameter and characteristic values have different meanings. Characteristics are determinable features of system elements, e.g., the geometry of a pipeline or a dam. For the simulation, they are constant unless being the subject of an investigation themselves. Parameters are also characteristics of system elements, but their unambiguous determination cannot be achieved sufficiently by measurement. They can only be measured at points but are related to larger areas (e.g., kf-value of soils) or represent a multitude of natural processes, e.g., a retention constant to describe the effluent concentration from a catchment area. They are subject to calibration and verification. To determine the behavior of system elements and the overall system, it is thus necessary to know characteristics and parameters.