Simulation Of Water Resources In The Upper Reaches Of The Yellow River And Its Future Evolution

The rapid development of human society has brought serious ecological and environmental crisis to human life.The resources,environment and population problems have become the key issues of coordinated development of nature,economy and society.The IPCC has released the "Climate Change and Water Resources"technical report in 2008 to further understand the current situation and problems of water resources.Water issues not only affect food security,but also have an impact on economic development and human life.The water resources problem of the Yellow River Basin is more serious.The contradiction between water supply and demand is very prominent.The situation of soil erosion and the phenomenon of drying up often occurs.The flow of the upper reaches of the Yellow River accounts for 38%of the whole river basin.Therefore,the management of river basin water resources has a vital role.Many scholars have studied the water resources in the upper reaches of the Yellow River,mostly based on the statistical analysis method,lacking the physical mechanism,and adopting the scenario hypothesis scheme for the future runoff change,which has great uncertainty.The SWAT hydrological model not only has a strong physical mechanism,but also has the characteristics of distributed computing,taking into account the differences in spatial distribution of geographical elements,and can simulate the material circulation and hydrological process in detail.Based on DEM data,land use data,soil data and climate data,this paper constructs the SWAT model suitable for the upper reaches of the Yellow River and simulates the hydrological cycle and hydrological elements of the study area.According to the future climate data(2041-2060),the future runoff and hydrological factors in the upper reaches of the Yellow River are predicted,and the current and future water resources status is analyzed.The relative contributions of human activities and climate change to runoff changes are analyzed.The main conclusions of this paper are as follows:(1)After establishing the attribute database of the study area and the parameter rate in the model,the SWAT hydrological model suitable for the upper reaches of the Yellow River is constructed,and the hydrological processes and elements can be simulated well.(2)Precipitation comparison of snowmelt is the main source of water in the upper reaches of the Yellow River.During the process of water balance,evaporation is the decisive factor,and the effect of groundwater on runoff can not be neglected.(3)The precipitation in the upper reaches of the Yellow River is increasing in the future,and the temperature change is not very significant.The change of climate is different in each sub-basin.(4)The future runoff of the study area is increasing,the peak value of the monthly runoff is decreased and the base flow value is increased,indicating that the future runoff value is stable and the frequency of floods is slowed down.(5)Future precipitation,evaporation and soil water will increase,groundwater will supply more to runoff.The year precipitation is more even in the future.(6)The current and future research period of the water resources are gradually increased and the wet index is increasing gradually.The semi-humid areas of study areas will gradually change to the wet areas.(7)The effect of human activities on runoff changes is increased at first and then decreased,mainly from 1990 to 2004,and the effect of climate change on runoff is continued until now.The amount of evaporation coutributing to the runoff change is slightly larger than that of precipitation.