afstrømningskoefficient

An afstrømningskoefficient, often translated as a runoff coefficient, is a dimensionless factor used in hydrology and civil engineering to estimate the amount of precipitation that will become surface runoff. It represents the ratio of the amount of surface runoff to the amount of precipitation that falls on a specific area.

The value of the afstrømningskoefficient varies depending on several factors, including the land cover, soil type, slope, and antecedent moisture conditions. For instance, impervious surfaces like asphalt or concrete have a high afstrømningskoefficient, typically close to 1, meaning almost all the rainfall becomes runoff. Conversely, vegetated areas like forests or meadows have lower coefficients, as vegetation and soil absorb a significant portion of the precipitation.

This coefficient is a crucial parameter in hydrological models used for flood forecasting, urban drainage design, and water resource management. By applying the afstrømningskoefficient to rainfall data, engineers and hydrologists can estimate the volume and rate of runoff that a watershed or urban area will experience. This estimation helps in designing appropriate infrastructure, such as storm drains, culverts, and detention basins, to manage stormwater effectively and mitigate the risks associated with flooding. Different types of surfaces and land uses are assigned specific afstrømningskoefficient values based on empirical data and established guidelines.