Extraction and analysis of the watershed features based on the Digital Elevation Model of the Miyun Reservoir
Zhu Hailing, Yang Xiaohui, Zhang Xuepei, Wei Tianxin, Lin Tianmiao
1.College of Soil and Water Conservation, Beijing Forestry University, 100083, Beijing;2.Chinese Academy of Forestry Sciences, 100091, Beijing;3.Plant Development and Management Center for Soil and Water Conservation,Ministry of Water Resources, 100038, Beijing: China
Abstract:The contours map of upstream in Miyun Reservoir in Beijing was the basic data for DEM generation supported by ArcGIS software. Drainage network and basin were graded by slope, aspect and drainage network extracted from DEM. Detailed statistical analysis were used to analyze the characteristic of divided drainage basin. The results showed that areas which heights ranged from 130 to 1 695 m and from 500 to 1 000 m occupied 55.03% of total area. Slope gradient more than 25 degrees took up 68.53% of studied area, where the potential strong erosion risks may exist. The ratio of shady slope to sunny slopes was almost 1∶1. The drainage network was divided into 9 levels, and totally 16 sub-basins.The soil erosion intensity and river confluence and storage capacity of each sub-basin were obtained from the analysis of the river density, the shape coefficient, the coefficient of river bend, the stream gradient and so on. The results could provide references of watershed management planning and hydrological model establishment.