Erosion Hazard Index of a Small Catchment in the Loess Plateau Based on Terrain Analysis

摘要

The Loess Plateau, with its heavily soil erosion, is limited in water resources and sensitive to hydrological environments. The eco-hydrological model TOPOG uses a sophisticated analysis of topography to describe the hydrological characteristics of a catchment in detail. This paper describes an integrated terrain analysis and steady-state hydrological modeling study of a small catchment on the Lvergou watershed, Loess Plateau China using TOPOG. The terrain analysis was based on a DEM (digital elevation model). The topographic attributes of each element, which included slope, aspect, upslope contributing area, and potential incident solar radiation, were calculated automatically. By setting different parameters, the results of steady-state simulation illustrated that the mapped distribution of Py (variable excess stream power index) and H (erosion hazard index) varied as a consequence of these different data inputs. Pv increased with an increase in uniform rainfall excess rate (Q); A comparison was made between a set of uniform Q and uniform fraction of soil exposed rainfall (Cr) values, and TOPOG was found to predict the expected trend that erosion hazard within the catchment increased with increasing uniform Q and uniform Cr values, and H increased sharply in the case of higher Q and Cr.