The Study On The Change Of Runoff And Sediment And Their Affecting Factors At Ying Luo-xia Station Of Heihe River

The most important and active part of the natural ecological system is river. It plays a pivotal role in the natural ecological and social economic system. At the same time, the basin system is a dynamic one which is specially sensitive to the climate change and human activities, yet the most active one is the river runoff-sediment change. The important research of the hydrology and water resources is the change of the runoff and sediment and their impact factors. The time course change of the runoff-sediment is the result of the coupling interaction of the climate changes and the human activities, which exists the definitive law in its evolvement, as well as the striking randomness. In the background of the global warming, studying the characteristics of the river runoff-sediment and knowing its evolution and influence factors, it not only helps to deepen the understanding of water cycle, water balance and the structure and the function of the basin, it also has the significant meaning of the reasonable exploitation and utilization of water resources in river basin. Heihe River is the second largest inland river in the northwest of China, and is also the largest runoff in Hexi Inland District. Heihe River basin water has become the main limited factor of the social and economic sustainable development. It is significant to institute the economic development strategy of regional society, promote the sustainable development of the industrial and agricultural production and the social economy sustainable development, and reflect Heihe River basin of Qilian mountain ecological environment by analysing the variation laws and the influence factors of the runoff-sediment change at Ying Luo-xia Station.The study on the change of runoff and sediment and their affecting factors at Ying Luo-xia Station of Heihe River is divided into four parts:The first part elaborated the background and the significance of the research, the research progress of the variation laws and the influence factors of the runoff and sediment both domestic and overseas, and then discussed the technical route and the main research methods.The second part studied the inter-annual variation trend of the runoff, the laws of the runoff mutation, intra-annual distribution characteristics of the runoff, runoff stability features and runoff change cycles; and then studied the inter-annual trend of the sediment, the laws of the sediment mutations, sediment intra-annual variation characteristics and sediment variation cycles.The third part analysed the effects of the temperature and precipitation, sunspot activity, ENSO circulation, watershed underlying surface on the runoff of Ying Luo-xia Station; the runoff's changes (precipitation) to the sediment, the relationship between the runoff and the sediment, established regressional model between the runoff and sediment relations, andfinally analysed the influences of human activities on sediment. In order to be more perfect, the fourth part summaried the main conclusions, and illustrated the deficiency of the paper, then put forward the problems which are needed to discuss in the subsequent research.