LAUSR

Abstract Methods for correct quantitative comparison of several terrains are important in the development and use of quantitative landscape evolution models, and they need to introduce specific modeling parameters. We introduce such parameters and compare two small terrains with respect to the link slope-valley for the description of slope deposits (colluvium) in them. We show that colluvium accumulation in small areas cannot be described by linear models and thus introduce non-linear models. Two small areas, Perdoel (0.29 ha) and Bornhoved (3.2 ha), are studied. Slope deposits in the both are mainly in dry valleys, with a total thickness M total up to 2.0 m in Perdoel and up to 1.2 m in Bornhoved. Parent materials are mainly Pleistocene sands aged ~ 30 kyr BP. Exponential models of multiple regression that use a 1-m LiDAR DEM (digital elevation model) explained 70–93% of spatial variability in M total . Parameters DH 12 and DV 12 of horizontal and vertical distances are introduced that permit to characterize and compare conditions of colluvium formation for various terrains. The study areas differ 3.7 times by the parameter DH 12 that describes a horizontal distance from thalwegs at which M total diminishes 2.72 times. DH 12 is greater in Bornhoved (29.7 m) than in Perdoel (8.12 m). We relate this difference in DH 12 to the distinction between types of the link slope-valley: a regional type if catchment area of a region outside a given small area plays an important role, and a local type when accumulation of colluvium from valley banks within a small area is of more importance. We argue that the link slope-valley is regional in Perdoel and local in Bornhoved. Peaks of colluvium thickness were found on thalwegs of three studied valleys by both direct measurements in a trench, and model surfaces of M total . A hypothesis on the formation mechanism of such peaks is discussed. The parameter DV 12 describes a vertical distance from a peak of colluvium thickness along valley bottom at which M total diminishes 2.72 times; values of this parameter differ 1.4 times for the study areas. DV 12 is greater in Perdoel (3.0 m) than in Bornhoved (2.1 m) thus indicating more sharp peaks of M total in Bornhoved. Exponential models allow construction of predictive maps of buried Pleistocene surfaces for both the terrains and calculate colluvium volumes with an error 4.2% for Perdoel and 7.1% for Bornhoved. Comparisons of buried and present surfaces showed that the latter are more smoothed, more strongly in valleys where flow branching is increased.