Study On Health Evaluation And Water Requirement Of Inland River In Arid Area

In recent years,after a series of water resources crisis caused by the lack of understanding of the water cycle and improper management of its own water use behavior,the harmony between people and water has become a key theme for current and future river development.Yeer Qiang River is the main source of water for living,industry,and agricultural irrigation in Kashgar,Xinjiang.The water resources are extremely scarce,and the efficiency of water resources utilization is not high.The water input to the Tarim River is insufficient,the watercourse is cut off all the year round,and river aquatic life is reduced,seriously restricting development of the local society economy.In this paper,the results of the three phases of RS interpretation are used as data sources to analyze the ecological environmental evolution of the Yeer Qiang River using GIS software.A variety of indicators and hydrological statistics methods are used to measure the runoff and temperature of the Yeer Qiang River from both annual and interannual perspectives.The evolution trend and variation characteristics of precipitation are analyzed;on this basis,relevant data are collected and arranged,river health assessments are conducted on the mainstream of Yeer Qiang River based on an ordered degree of entropy model,and the ecological needs of the Yeer Qiang River are divided into river channels and outside the river.Water was estimated.The research results can provide theoretical basis and technical support for the rational use of water resources in the river basin,water conservancy planning,and can also provide reference for similar research in small and medium-sized rivers in arid regions.The results are as follows:(1)Among the ecological factors,the total area of the Yeer Qiang River grassland and wetland decreased by 2432.57 km~2 and 91.8 km~2,respectively,and the area of the remaining land types increased;in the three periods,the coverage of vegetation with inferior cover was dominant,and the coverage area of vegetation increased rapidly(growth The rate was 11.67%);the total area of soil salinization increased year by year,reaching 1579.89 km~2 in 2016.During the year,the runoff of the Yeer Qiang River is mainly concentrated in 75%of annual runoff in the period from June to September.The interannual increase is the trend(U=2.46).Precipitation is mainly concentrated in the period from May to September and accounts for66%of the year.(U=2.72);The temperature distribution during the year is extremely uneven,with no significant increase(U=1.62).The correlation analysis showed that there was no significant negative correlation between winter temperature and runoff(-0.323),and the correlation between summer temperature and runoff(0.81)was the best.The combined sequence of summer temperature and runoff changed in 1997.(2)Based on the PSR model and the“best possible status”reference standard,a total of 23 indicators of river health assessment index system were constructed.The evaluation results showed that the comprehensive health index of the mainstream of the Yeer Qiang River Karst-Eric Tumu River section was0.529.The comprehensive health assessment level III is in a sub-health state,that is,the critical state of river health transition from healthy to unhealthy.Among them,the overall health index of the S1 segment is0.546,and the total health index of the S2 segment is 0.511,both of which are sub-healthy.The health index of the S1 segment is slightly higher than that of the S2 segment,and the health index of the whole river is ranked as the response health index(0.537)>State Health Index(0.530)>Stress Health Index(0.521).The evaluation results are basically in line with the actual situation.The health of rivers in the mainstream of the Yeerhe River has been threatened,and river health maintenance is imperative.(3)The calculation results of the ecological water demand in the river channel of this study:under the conservative target of the annual ecological water demand in the river under consideration of water demand and self-purification of the sediment,the target is 11.70×10~8m~3,and the best target is 23.76×10~8m~3.The calculation results of the ecological water requirement outside the river:The calculation result of the submerged evaporation method is 6.79×10~8 m~3,the calculation result of the area fixed method is 6.35×10~8m~3,and the average value is 6.57×10~8 m~3.The calculation results of the ecological water demand in the river course and the related literature are close,and it also meets the task of ecologically transporting 3.3×10~8 m~3 of water to the Tarim River.The calculation of ecological water demand of natural vegetation outside the river channel uses two different calculation methods.The basic calculation results are basically the same.reliable.