Study On The Process Of Water Dissipation In The Yarkant River Basin

As one of the important sources of the Tarim River Basin,the reasonable development and utilization of water resources and ecological environment protection of the Yarkant River were related to the survival and development of the basin.Under the influence of climate and human activities,conflicts in water use among regions had become increasingly prominent.Carrying out the analysis of water dissipation in the Yarkant River,revealing the law of water dissipation in the river,could provide a basis and reference for optimizing the rational allocation of water resources,solving outstanding problems of regional water use contradictions,and future planning and development.In the case of analyzing the changes of water and soil resources in the Yarkant River Basin in the past 20 years,the watershed hydrological station data was collected,and the drainage process of the river basin was analyzed preliminary.Finally,the runoff process of the Yarkant River was simulated by the SWAT model,and the water dissipation process in the runoff was restored and separated.On this basis,the land use data from 1990 to 2015 was input into the SWAT model to analyze the impact of land use changes on the water dissipation of the Yarkant River.The main conclusions are as follows:(1)Since the 1990s at the end of the last century,the main and tributary streams had entered the period of high water.In the case of an increase in runoff in the source area,due to the continuous increase in social and economic water consumption,the amount of surface water resources used had increased.According to the analysis of water resources evaluation,the average self-produced water resources in the Yarkant River Basin for many years was 7.67 billion m~3,of which the surface water resources were 7.55 billion m~3,accounting for 98.4%of the total water resources;the unduplicated amount of surface water and groundwater was 1.1 Billion m~3.(2)According to the analysis of land use change,the continuous increase in the area of arable land consumed more water resources.Therefore,as the inflow of water from the upper mountainous area increases,the amount of water discharged decreases.The 30a cultivated land in the study area increased from 5030.84km~2 in 1990 to 8487.57km~2 in 2018,an increase of 68.7%.Through the analysis of the overall landscape pattern,the landscape of the Yarkant River as a whole had tended to be fragmented in the past 30years,and the connectivity between various landscape typed Enhancement,the diversity of the landscape continued to increase,and the heterogeneity of the landscape was getting higher and higher.Analysis of vegetation coverage changes showed that the vegetation coverage of the Yarkant River showed an overall improvement and a partial deterioration trend.Among them,the increase trend was significant from 2000 to2010,and the later period was significantly reduced from 2010 to 2018.Significant decreased in the vicinity of towns with more human activities and the left bank of downstream rivers.(3)Through the analysis of hydrological sites,the loss of river water volume and the incoming water showed a positive correlation.The average value of river water loss from 2001 to 2017 was 2.746 billion m~3,and the river water loss rate was 33.11%.Among them,the river water loss in 2009 was the smallest,at1.76 billion m~3,and the river section in 2012 was the largest at 4.178 billion m~3.Comparing the water inflow,diversion and channel water loss in different periods of time,it can be seen that the average inflow of the Kaqun canal head+Jiangka from 2012 to 2017 was more than that in 2001 to 2011(the average inflow increased by 993 million m~3),The amount of water diversion increased from 6.172 billion m~3 to7.335 billion m~3,the loss of river water volume and the amount of receding water decreased,and the runoff of the Henyazi section increased(513 million m~3).(4)The simulation results showed that the average annual channel loss of the Yarkant River showed a characteristic of decreasing along the flow path.This was due to the large amount of runoff behind the mountain,the relatively large water surface area in the channel,and the flow of the water flowing through the front of the mountain with strong leakage.In the accumulation transition zone,the water leakage of the river channel was large.With the irrigation and diversion along the way,the runoff in the river channel gradually decreased,the water surface area was relatively small,and the channel loss was reduced accordingly.In the past 20 years,the annual average inflow of water from Kaqun Station and Jiangka Station was 8.299 billion m~3,the average annual discharge volume of 48th Regiment Ferry was 1.984billion m~3,and the average river loss from Kaqun and Jiangka to 48th Regiment Ferry was 6.354 billion m~3.Among them,the loss of natural river water volume was 1.586 billion m~3,accounting for 24.97%,and the national economic water consumption was 4.767 billion m~3,accounting for 75.03%.The total water loss from the 48th regiment Ferry to Herniaz River was 458 million m~3,accounting for 47.27%of the national economic water consumption,and 511 million m~3of natural river water loss,accounting for 52.73%.In the loss of natural river water volume,the leakage of the river channel was 178 million m~3,accounting for34.83%,and the evaporation of the river channel was 333 million m~3,accounting for 34.37%.