Landform evolution modeling of a small catchment in the loess plateau

Abstract

Chinese loess plateau, a huge landform object, is one of the most serious regions of soil and water loss in China even in the world. Influenced by this, the geomorphologic feature there has been changed considerably. In order to accurately model the process of small watershed landform evolution, this article established a set of small watershed runoff and sediment yielding and landform evolution model, which is based on the modern spatial information technologies such as GIS, GPS, RS, terrestrial laser scanning, and with the support of the long hydrological and weather data which gauged by some scientists. The main achievements are as follows: According to the physical geography features of the Loess Plateau and the results of previous studies, the article designed the model of runoff, convergence and sediment yield which possessed some physical-based on raster unit with high-resolution. According to sediment transport ratio of the natural small watershed was 1, the article constituted the basin sediment model, calculated the storm runoff, sediment volume and the annual erosion of sediment yield formed by rainstorm cumulative sediment yield data, established catchments landform evolution model which only needed underlying surface parameters, modeled the process of landform evolution; several key and important parameters were selected in the model for analyzing the sensitivity of parameters, spatial distribution and the uncertainty of prediction. The process of runoff, sediment yielding and landform evolution in a typical small watershed was simulated. The database of the parameters of hydrology, weather, and climate was built. Small watershed runoff and sediment production process was simulated by using the developed information system and high spatial and temporal resolution parameter data. On the basis of simulation results of Runoff and sediment yield, this article established experimental watershed geomorphic evolution model, simulated the process of small watershed landform evolution in two hundred years, analyzed quantitatively the rule of landform evolution.