Spatial distribution and morphologic characteristics of gullies in the Black Soil Region of Northeast China: Hebei watershed |
| |
| Authors: | Tianyu Zhang Gang Liu Xingwu Duan G V Wilson |
| |
| Institution: | 1. State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, Northeast Normal University, Changchun, P.R. China;2. State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, P.R. China;3. State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, P.R. China;4. Watershed Physical Processes Research Unit, USDA-ARS National Sedimentation Laboratory, Oxford, MS, USA |
| |
| Abstract: | Gully erosion in the Black Soil Region of China has posed a threat to food security. This study aimed to determine the spatial distribution and morphologic characteristics of gullies in the region and their topographic thresholds. A 28 km2 watershed was surveyed and 117 gullies measured. The results showed that: (1) Gullies were distributed equally on both hillslope and valley floor positions, with a total gully density of .66 km/km2. (2) The mean depth, width, and cross-sectional area of gullies were .74 m, 2.39 m, and 2.43 m2, respectively. These characteristics varied among gullies according to their topographic positions and slope gradients. Individual gully volume (V) was well predicted from gully length (L) by V = 2.08L0.96 (r2 = .66). Total gully volume (V) of each sub-watershed was predicted from mean slope gradient (S) and drainage area (A) as V = 275800S ? 8600A (r2 = .73). (3) Gully erosion was more serious in steeper sub-watersheds and steeper hillslope positions. Gullies were wider in regions with relatively larger drainage areas, except for those developed in the main valley. The topographic threshold for gully initiation was S = .10A?0.34, which indicated gully erosion was dominated by surface runoff. (4) Human activities, such as road construction, played a significant role in gully erosion. |
| |
| Keywords: | Gully erosion topographic threshold slope gradient drainage area human activity crop yield |
|
|
