hydrographen

Hydrographen are graphical representations of how the discharge of a river or stream varies over time. In hydrology, a hydrograph shows the relation between time and flow, usually in cubic meters per second, in response to precipitation events, snowmelt, or groundwater inputs. The term Hydrographen is the German plural form of hydrograph, and in English-language literature the plural hydrographs is used more commonly; however, some multilingual texts retain the German form.

Typical components of a hydrograph include the baseflow level, the rising limb as discharge increases, the peak discharge, and the recession limb as discharge declines. Key metrics derived from hydrographs are time to peak, peak discharge, and total runoff volume (area under the curve). Hydrographs can be recorded from stream gauges or produced by hydrological models and are often graphed on the same scales to compare events.

Applications include flood forecasting, water resources planning, and the design of hydraulic structures. They also support hydrological model calibration, regionalization studies, and the assessment of climate-change impacts on runoff behavior. Limitations of hydrographs include sensitivity to measurement interval, method of baseflow separation, and data quality, as well as their inability to fully capture dynamic catchment processes over long periods.

See also: hydrograph, discharge, rainfall-runoff model, unit hydrograph.