The Relationship Between EC-economy Factors And Runoff And Sediment Varia Tion In Wuding River Watershed

Wuding River is an important tributary of the middle reaches of the Yellow River and flows through the Loess Plateau region of northern Shaanxi. In recent years, with the socio-economic development and changes,especially with the growth rate of migrant workers continue to decline, a tendency to rural and agricultural economic development of anti-urbanization of the "city" phenomenon,which make the agricultural economy into a new development stage. Therefore, in the context of the increasing frequency of human activities and the implementation of the plan of returning farmland to forest and grass in the loess area,the traceability analysis of runoff and sediment variation is strengthened and the response between economic, ecological and runoff and sediment is established. And the relationship between runoff and sediment changes has an important theoretical significance and practical value.Based on the Mann-kendall and Pettitt hydrological statistics, double-cumulant and anomaly accrual curve method, combined with GIS analysis technique, the regression analysis and path diameter of SPSS software were used to study the characteristics of runoff and sediment in Wuding River Watershed. This paper studies the relationship between the eco-economic factors and the changes of runoff and sediment in the watershed, and studies the differences between the economic, ecological and water and sediment in the different scale watersheds of the Wuding River, so as to analyze the ecological and economic sustainable development. The main results of this paper are as follows:(1) Runoff and sediment change point test and trend changes: the past 30 years hydrological datas from the Baijiachuan and the hydrological station watershed of Wuding River Watershed, the runoff and sediment showed a decreasing trend in Wuding River Watershed, There was a significant positive correlation between the Fenhe River and its tributaries. In the abrupt change test of runoff, the first variation point of runoff in the Haihe River, Luhe and Haimuotou watersheds were concentrated between 1994 and 1997, and the second mutation point were concentrated between 2003 and 2005, The first mutation point occurred earlier (1988), and the second mutation point was consistent with the tributary mutation time. This is mainly affected by the construction of the Three North Shelterbelt in the watershed and the ecological construction such as returning farmland to forest (grass). The abrupt change time of the Wuding River Watershed and its tributaries were concentrated before and after the 1990s.(2) The temporal and spatial evolution of the ecosystem elasticity and its relationship with the changes of runoff and sediment: From the statistical data of the ecosystem elasticity in different regions, the ecosystem elasticity showed a significant variation tendency in the Heimutouchuan and Wuding River Watershed. Changes of the South were generally higher than the northern region, and the changes continue to increase with the interannual variation. From the relationship between the ecosystem elasticity of the two river watersheds and the change of runoff and sediment, there was a strong negative correlation between the two groups. The ecological environment of the watershed improved continuously, which made the soil erosion decrease. The runoff and sediment showed a decreasing trend. And the benefits of runoff reduction and sediment reduction in the Heimutouchuan watershed are significant.(3) The relationship between ec-ecological factors and changes of runoff and sediment in different scale watersheds: Through multiple regression and path analysis, it could be seen that the ecological factors of Haimuotouchuan watershed had a significant effect on the change of runoff and sediment. The economic factors were mainly related to the economic development.The effects of economic factors on runoff and sediment tend to be unified in the Wuding River Watershed. The agricultural factors and natural factors had a significant impact, and the effect of water conservation and industrial factors were weaker.