Characteristic parameters of typical watershed based on DEM in the Loess Plateau, northern China

Watershed features and stream features derived from DEM (digital elevation model) of Caijiachuan Watershed in Jixian County of Shanxi Province, northern China were extracted and statistically analyzed. The results showed that: with watershed area increasing, the length of main stream, overall length of main stream and branch, meander coefficient and the coefficient of basin shape all increased; the basin asymmetry factor and average elevation both decreased; the drainage density, stream gradient and average slope decreased at the beginning and then stayed stable. With weak ability to prevent from flooding, the study area must be protected urgently for the severe soil erosion. Concretely, the stream gradient should be controlled under 6.1%, the drainage density below 058 km/km2, and the watershed under 10 km2 must be the key to deal with the water and soil conservation in Caijiachuan Watershed. The area with slope above 25° occupied 52% of the overall area, so flooding is apt to take place there and the conservation of soil and water should be paid more attention to.