Study On Water System Structure And Connectivity In Daqing

The morphological structure and connectivity of river systems have an important impact on the allocation of water resources and water security in river basins.Under the increasingly severe background of water resources shortage,as an important way to improve water resources capacity,river-lake water system connectivity has become a new strategic policy.Daqing River Basin is located in the hinterland of Beijing-Tianjin-Hebei Province,and Baiyang Lake belongs to Daqing River Basin in water system,which is an important ecological functional area of Xiong’an New District,and its water resources play an important role in the economic development of surrounding areas.In recent years,with the development of social economy and the interference of human activities,the Middle Route Project of South-to-North Water Transfer and its supporting projects,as well as the Yellow River Diversion Project,have been built within the Daqing River Basin.A large number of reservoirs and sluices have been built for flood control and water storage.The construction of artificial water system and water conservancy project will definitely affect the water system structure and connectivity in the basin.In this paper,taking the three-level division of water resources in Daqing River Basin as a unit,the changes of river system morphology and connectivity under the background of artificial water system and water conservancy project construction are studied.The research results can reveal the influence of human activities on river system morphology and connectivity in Daqing River Basin,and provide basic theoretical basis for rational planning of water system and construction of water conservancy projects.The main research contents and achievements are as follows:(1)The linear and areal water systems in Daqing River Basin are extracted by Arc GIS,ENVI and Bigemap software.The water system morphology and structure of each water resources division are studied from two aspects of water system quantitative and structural characteristics.The results show that the plain area of Daqing River Basin is better than the mountainous area in both quantitative and structural characteristics,indicating that the water system density and water system development in plain area of Daqing River Basin are better than those in mountainous areas.(2)Based on fractal theory,the fractal dimension values of water systems are calculated with or without artificial water system of diverting water from the Yangtze River and the Yellow River as a unit,the range is between 1.0412-1.0650 and 1.0300-1.0644.The results show that artificial water systems of diverting water from the main branch of the Yangtze River and the Yellow River increase the fractal dimension values of water systems in Daqing River Basin and each division,and the more artificial water systems,the greater the promotion effect,indicating that human activities have affected the development of water systems to a certain extent.The fractal dimension value of water system in Daqing River Basin is 1.0563,which indicates that the water system in Daqing River Basin is in the young stage of erosion development,and the density of river network is small,which is mainly manifested by the undercutting erosion of rivers.(3)Based on the theory of landscape ecology,the water system connectivity with or without artificial water system of diverting water from the Yangtze River and the Yellow River and with the construction of reservoirs and sluices are calculated.The results show that the construction of artificial water system of diverting water from the Yangtze River and the Yellow River improves the water system connectivity of the Daqing River basin,while the construction of reservoirs and sluices reduces it.We can reduce its influence on the connectivity of water system by rationally constructing reservoirs and sluice projects and optimizing water dispatching methods.