kaltevuusmin

Kaltevuusmin is a term used in geomorphology and geotechnics to denote the minimum slope or inclination required for a particular process to initiate or continue, such as sediment transport, erosion, or landslide triggering, under a defined set of conditions. It is described as a threshold parameter that links hydrodynamic or gravitational forces with material resistance.

Etymology: The word derives from kaltevuus, Finnish for slope or inclination, combined with min, a shorthand for minimum. The term appears primarily in Finnish-language technical literature and in translated works within slope stability and sediment transport research.

Theoretical basis and measurement: The concept can be expressed in both dimensional and dimensionless forms. In river and coastal engineering it relates to the onset of sediment transport where the Shields parameter reaches a critical value; in slope stability contexts it corresponds to the gradient at which the factor of safety equals one. Practically, kaltevuusmin is estimated through laboratory flume tests, field observations, or numerical models, calibrated for grain size, density, fluid properties, and roughness.

Applications: It informs design criteria for culverts, embankments, and river restoration projects; it also supports hazard assessment for landslide-prone slopes and channel incision. It is sensitive to changes in water discharge, vegetation cover, and soil moisture, making it an indicator of transient stability in changing environments.

Limitations: As a threshold parameter, kaltevuusmin depends on assumptions about material properties and flow regime; natural systems exhibit spatial heterogeneity and temporal variability, which can shift the effective minimum slope. Caution is advised when extrapolating from small-scale experiments to field-scale conditions.

See also: Sediment transport, Shields parameter, Slope stability, Erosion threshold, Geotechnical engineering.