Digital elevation model-based watershed geomorphic entropy for the study of landscape evolution of a watershed geomorphic system in the loess landforms of China

Abstract

Although the concept of entropy in landscape evolution was proposed over 40 years ago, previous studies of geomorphic entropy paid little attention to the applications of geomorphic entropy in the erosional watershed geomorphic system on the Loess Plateau in China. Therefore, we propose a new concept of entropy called watershed geomorphic entropy (WGE) and its method of calculation based on a digital elevation model and the principles of system theory. To study the geomorphic significances of WGE, we applied the WGE to an artificial rainfall experiment that was originally designed to study erosional processes in a small open watershed geomorphic system on the Loess Plateau. Our study shows that the decrease of WGE in an open watershed geomorphic system means a gradual erosional or erosion-dominated landscape evolutional process and the change of WGE shows a perfectly positive linear correlation with the measured sediment yields of the outlet of the watershed system under our experimental conditions. In addition, to some extent, the decrease of the change of WGE also reflects the reduction of total potential energy of a specific erosional, or erosion-dominated, open watershed geomorphic system.