Isotope Runoff Segmentation Of The Xiyin River Basin In The Lenglongling Of The Qilian Mountains

In recent years,the flow rate of the upper reaches of the Shiyang River has increased,which has led to a series of ecological problems.The reason of the runoff rate has become a hotspot.The water source components of the runoff in the Shiyang River Basin are more complicated,including not only the precipitation and groundwater in the area,but also the melting water generated by the high altitude ice and snow ablation.Therefore,it is very difficult to explain the confluence of the confluence,Scientific basis.Based on the samples of different water bodies collected from lenlongling glacier in the upper reaches of the Shiyang River Basin in May 2015and May 2016,the hydrothermal stabilized isotopes of the precipitation,snow melt water and river runoff in the basin The results show that the contribution rate of the runoff and the uncertainty of the runoff in the watershed are analyzed and discussed.The isotopic factors of the upper reaches of the Shiyang River are analyzed and discussed.Study on Runoff Segmentation.The study will help to clarify the process and mechanism of runoff formation in alpine and arid mountainous areas in the monsoon boundary and improve the understanding of the runoff supply and confluence processes of the complex climate system in the alpine watershed.It provides the development and improvement of the distributed hydrological model convergence and ice-Physical basis,but also for the downstream oasis area comprehensive control of water resources and rational use of scientific basis to enhance the formation of water resources in the Shiyang River Basin and its transformation of the cognitive level.The main conclusions drawn from the study are as follows:?1?The slope of the regional local waterline is lower than that of the global atmospheric waterline and the Chinese atmospheric waterline.The intercept is close to that of the global atmospheric waterline and the Chinese atmospheric waterline,which is consistent with the precipitation in the arid and semi-arid area.Characteristics,indicating that part of the precipitation from the local water vapor cycle.The study area is located in the high altitude inland area,and the rainwater undergoes a certain degree of secondary evaporation effect during the landing process.Heavy isotopes are abundant in rainwater,resulting in a decrease in slope and atmospheric waterline.Precipitation isotope has a certain seasonal effect,6-8 months continue to enrich,8-10 months gradually depleted.In the study area,the temperature effect is significant in June and October,and the effect of"precipitation"is obvious.The reason is that the period of precipitation increase is the period when the temperature rises obviously,and the"temperature effect"is?¹⁸O"Precipitation"effect can't be reflected.?2?The seasonal variation of the surface snow was significant,showing a trend of autumn and winter low,increasing from June to October,decreasing gradually from January to October,the highest value appeared in October,the lowest value appeared in January The?¹⁸O and the elevation showed a weak negative correlation,but the correlation was weak.Ice and snow melt water changes less than the surface snow,basically included in the surface snow range,and the average is greater than the average of the surface snow.Seasonal variation is not obvious,and the isotope values are higher in May and September,and the other months are relatively stable.?3?Hydrogen and oxygen stable isotopes in river water do not accord with the"elevation effect"rule.?D and?¹⁸O showed a tendency to increase from the first decrease.From the seasonal point of view,the value of the isotope value of the upstream fork in the upstream area is relatively large?-3.01‰?,and the fluctuation range of the two downstream sampling points is relatively small?<-1.74‰?,three sites In February,the change of?¹⁸O value showed a change of?18O value from June to June.?4?Based on the isotope difference tracer method,the source of river water supply in the study area is estimated.It is concluded that the contribution rate of precipitation and glacier meltwater to runoff in the Xiying River Basin of the upper reaches of the Shiyang River-the Qilian Mountains is 63.77%and 36.23%respectively,which indicated that the water body in the Xiying River Basin was mainly precipitation and glacier melting water,and the precipitation in the rainy season became the main source of runoff.The runoff component of the study area shows a more complicated state.The seasonal variation of the contribution rate of ice and snow meltwater and precipitation to the river is not obvious.From June to July,the runoff of the river is increasing,and the ice and snow melt water is the main recharge method.The proportion of precipitation in the river water showed an increasing trend,becoming the main source of supply.?5?The uncertainty analysis of the runoff segmentation in the study area shows that the error caused by the spatiotemporal change of the tracer is relatively larger than that caused by the test method.Whether it is test method error or tracer time difference error,are the most significant in September,the highest temperature during the period and the most rainfall,strong evaporation results in unbalanced fractionation effect,and therefore have higher uncertainty.The uncertainty of the error caused by the spatial heterogeneity of the tracer is mainly caused by the temporal and spatial variation of the tracer of precipitation?and snow melt water?,the temporal and spatial variation of the river is relatively small,and the effect on the uncertainty is weak.The reason of the analysis is due to the study of selected watershed elevation changes,the basin within the altitude difference,resulting in precipitation and snow melt water oxygen isotope changes in time and space larger.