2022 Volume 42 Issue 3 Pages 57-68
Limnogeomorphogy is the branch of geomorphology studying landform changes and processes in lake-catchment systems. Estimation of erosional force in the systems is closely related to limnogeomorphological studies. Earth surface processes and changes in the systems are generally printed in lacustrine sediments, which are of great use for considering erosional forces. Two time-intervals are introduced for discussion of the forces; one is the short interval during the past 10 years (instrumental observation period) for a small system, and the other is the long one during the past some 10-100 thousand years for large systems. The erosional force can be expressed as mathematical equations using dominant periods in sedimentation rate both for the short and long intervals in the systems. Erosion ratio for volcanic mountain dissection and evolution of drainage density are discussed for the long interval using mathematical equations with the erosional force estimated from sedimentation rate in Lake Biwa. The calculated results for the dissection and evolution show that the establishment of the erosional force in the equations is of value for understanding the temporal changes.
