Research On Gully Erosion And Seabuckthorn Dam Sediment Intercepting Effect In Coarse-Sediment Producing Area Of Yellow River Basin

The sediment yield of the coarse-sediment producing area in the midlle Yellow River basin accounts for 65% of the sediment yield of Longmen station, coarse sediment accounts for 80% of the sediment yield of longmen station. Soft rock area accounts for 1.16Ñ…104km2, which accounts for 7.5% of the sediment yield of 15.6Ñ…104km2 coarse-sediment producing area, the sediment yield of grain-size large than 0.025mm accounts for 80% of the sediment yield of coarse-sediment producing area. Most of the coarse sediment will deposit in the river channel of middle and lower reach of Yellow River, raising river bed, silting up reservoir, causing flood disaster. So the control of the water and soil loss and the sediment into river is the key of Yellow River sediment problem. The sediment mainly come from the gully erosion, and seabuckthorns flexible dam is an effective method to prevent gully erosion, so the study on gully erosion and sediment intercepting effect in coarse-sediment producing area of Yellow River basin is significant.The research area of this paper is Dongyizhigou small watershed lies in soft rock area in Dongsheng city of the inner Mongolia. Large metrical data were gotten by times of field measures. associating with past researches, starting from phenomena, deducing by logic, demonstrating by metrical data, the main research contents and findings were essentially as follows:1. Study erosion of ditch slope, put forward a mechanism of erosion of ditch slope, and use this to analyze and explain the landforms in soft rock area;2. Study gully characteristic, assort gullies into rills and main channels, analyze respectively their characteristics and establish gully erosion calculational method;3. Study runoff erosion, put forward that runoff erosion can be divided into three periods such as acceleration period, deceleration period and stabilization period, analyze respectively the gully property in each period, and establish gully current velocity calculational method;4. Study the composition of gully erosion, put forward that the gully erosion develops in three direction of width, depth and far, analyze erosion distribution based on erosion sorts and positions, and put forward treatment countermeasure;5. Study the silting form in seabuckthorns flexible dam, based on metrical data of years and past research of indoor test, explain the genesis of silting form, and put forward a mechanism of silting form.6. Study silting process in gully, put forward that the gully silting can be divided into three periods such as stabilized silting period, relatively stabilized period and completely stabilized period under the action of three sorts of silting energy, analyze respectively each period and put forward a gully silting mechanism.