Geomorphological Processes and Human Impacts in River Basins
(Proceedings of the International Conference held at Solsona, Catalonia, Spain, May 2004). IAHS Publ. 299, 2005, 197-204.Anthropogenic impacts on sediment discharge in the dry-hot valleys of SW China—the example of Longchuanjiang
X. X. LU1, Y. M. ZHU1,2 & Y. ZHOU2
1 Department of Geography, National University of Singapore, 10 Kent Ridge Crescent, 119260 Singapore
geoluxx@nus.edu.sg
2 Department of Environmental Science, Kunming University of Science & Technology, Kunming, Yunnan, 650093, China
Abstract
The sediment discharge data measured in a dry-hot valley, Longchuanjiang basin in the Lower Jinsha tributary, were analysed with Mann-Kendall, Seasonal Mann-Kendall and Sen’s tests. In the upper reach, water discharge and sediment yield increased by 2.0 and 2.48% per year, respectively, during the period from 1970 to 2001. In the lower reach they increased by 1.95 and 3.94%, respectively. The sediment discharge showed a significant increase (0.05 at Xiaohekou and 0.01 at Xiaohuangguayuan), despite numerous reservoir constructions and insignificant changes in water discharge. This could be attributed to the intensification of human activities, especially those related to land surface disturbance such as deforestation and afforestation, expansion of agriculture land, and road construction. The increase was more significant in the lower reach of the river due to the dry-hot climate. The profound increase observed in sediment discharge has significant implications for effective management of the on-going Three Gorges reservoir project.Key words afforestation; dams; deforestation; dry-hot valley; sediment discharge