Gully is a landform with narrow channel cutting by runoff on hillslope. Gully landform indicates rapid soil erosion and initiation of denudation process on hillsope. After gullies are formed, a large quantity of sediment is produced by the incision, lateral erosion and head-cutting. This study aims to estimate the sediment yield due to gully erosion in the Baishi watershed of Shihmen Reservoir. We measured the morphology change of gullies by using Pulse Laser Total Stations, and interpreted the gullies from aerial photographs. Then, sediment yield from gully erosion was estimated in the watershed. The results show that gullies can be categorized into two types, active gully and stable gully, based on its sediment yield. Active gully, which is in the initial stage of gully evolution, has an average sediment yield of 0.2758 m 3/m 2. In contrast, stable gully, which is highly-developed, has with a smaller sediment yield of 0.0108 m 3/m 2 relatively. There are 120 gullies interpreted from aerial photographs, which 41 are polygon shapes and 79 are line shapes. The total sediment yield from gully erosion in the Baishi Watershed is 27,744 m 3 during July to December in 2006. The annual sediment yield from gully erosion is 176,280 t yr -1 based on the assumption of linear ratio of sediment yield with accumulated rainfall. The gully erosion contributes 14% of annual sediment in the watershed, comparing with the landslide erosion of 1,023,480 t yr -1 and soil erosion of 30,960 t yr -1. Gully erosion is a significant source of sediment yield in the watershed.
|Number of pages||16|
|Journal||Journal of Taiwan Agricultural Engineering|
|Publication status||Published - 2012 Jun 1|
All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences(all)