|
|
|
| Spatial-temporal variation of annual sediment yield during 1960—2000 in the Jinghe Basin of Loess Plateau in China |
| Liu Gefei1， Yu Pengtao1， Wang Yanhui1， Tu Xinwu2， Xiong Wei1， Xu Lihong1 |
| Spatial-temporal variation of annual sediment yield during 1960—2000 in the Jinghe Basin of Loess Plateau in China |
|
|
|
|
Abstract Quantitative estimation of river sediment yield and its spatial-temporal variation within a river basin is prerequisite to develop an effective strategy for soil erosion control. In this study, the Jinghe basin, where high soil erosion exists, was chosen as representative research area. Based on existing long-term records of 11 hydrological stations, the total river basin was divided into eleven river courses to quantify the spatial-temporal heterogeneity of annual sediment yield during the period of 1960—2000. The results indicated that there was a strong annual sediment yield in Jinghe Basin in the 1960’s, it was 302.49million t/a for the total river basin and the corresponding annual sediment modulus was 6672t/(km2·a) on average. There was a visible spatial heterogeneity of annual sediment yield within the basin. The total area of river courses with sediment yield intensity grades of “extreme” and “severe” accounted for 72.6% of the total basin area, which contributed 86.0% of the annual sediment yield of the total basin. The river courses with sediment yield intensity grade of “moderate” and “slight” covered 27.4% of the total basin area and contributed 14.0% of annual sediment yield of total basin. Since 1970’s, the annual sediment yield in Jinghe Basin reduced. Compared with that of 1960’s, the average of annual sediment yield for the whole basin in 1990’s decreased to 265.78million t/a, with a reduction ratio of 12.1%. However, 93.5% of this sediment reduction took place in the river courses with “extreme” grade of sediment yield intensity. This demonstrated that the river courses with “extreme” grade of sediment yield intensity made a substantial contribution to the sediment reduction in Jinghe Basin, especially the river courses in the west region of Jinghe Basin with higher precipitation and better vegetation coverage; while the sediment yield and contribution from the areas with other grades of sediment yield intensity was basically unchanged. Under the future regional climate change with increasing erosive rain-storms, the semi-arid regions of the Jinghe Basin with lower vegetation coverage and resistance against rainfall erosion should be listed as the key area for erosion control.
|
|
Received: 18 April 2011
|
|
|
|
|
|
|
