Assessment Of Spatial And Temporal Variability Of Green And Blue Water Flows In The Xihe River Basin,China

Water is part of the surface environment.In assessing the impact of water resources on agricultural production processes in semi-arid regions,water resources are divided into blue water and green water.Blue water refers to visible surface runoff and liquid water from subsurface runoff,which is water in rivers,lakes,reservoirs and aquifers.Green water refers to the water needed to infiltrate the earth's surface for plant growth.Green water can be divided into green water flow and green water storage.Green water flow is the actual evapotranspiration,that is,the amount of water in the atmosphere,and green water storage is the amount of water in the soil.The proposal of blue water and green water puts forward new ideas for the evaluation of water resources.In the past,scholars paid more attention to the study of blue water resources,and the green water resources that play an important role in the ecological environment are often ignored.Green water resources are an important part of regional ecological environment water use in semi-arid and semi-humid regions and their north.Therefore,the research on blue water and green water has been widely concerned by domestic and foreign scholars.In China's semi-arid and semi-humid northeast,the research on water resources is limited to the discussion of runoff,while the research on blue water and green water on the scale of watershed is still rare.In this study,SWAT model was used to simulate the spatial and temporal distribution pattern of blue water and green water resources in the basin from 1975 to 2015.The spatial and temporal distribution patterns of blue water and green water in the basin were analyzed.The factors influencing land use change and climate change on blue and green water resources are discussed through different schemes.The study shows that the main part of the water cycle in the xihe river basin is the green water resources,the green water coefficient can reach 68%,and the water cycle in the basin depends more on the green water resources.The upstream of the river basin is an agricultural area,which mainly develops its economy by planting crops.The middle and lower reaches of the city are located in the suburbs and are mainly used for growing fruits and vegetables.Water for crops is mainly provided by green water resources,so the large consumption of green water reserves will have acertain impact on the green water resources in the basin.Green water resources are of great significance to the rain-fed crops production in xihe river basin.The spatial and temporal distribution of blue water resources is positively correlated with precipitation.Affected by the underlying surface of the city,the basin shows a trend of decreasing green water resources from the upstream to the downstream.It is particularly important to divide green water resources in special dry seasons.The growth of green water resources in xihe river basin is closely related to the change of land use.However,human activities have a great impact on the land use pattern of the river basin,which has a certain impact on the distribution of water resources in the river basin.