Study On Hydrological Health Assessment And Ecological Flow In Datong River Basin

Datong River Basin is located in arid and semi-arid area.Although the natural water resources condition is good,in recent years,As many water conservancy projects were built,which makes a mass of water resource be intercepted,It is disadvantageous to the water environment of the basin.The hydrological conditions,economy and ecological environment in the lower reaches will be threatened.Therefore,it is necessary to evaluate the hydrological health of Datong River,and explore the suitable ecological flow of Datong River,so as to provide technical support for the health management of Datong River.This paper takes Datong River as the research object,starting from the characteristics of runoff and meteorological changes of Datong River,studies the impact of climate on runoff.In order to explain the impact of water diversion project and reservoir hydropower station construction on the hydrological health of Datong River in human activities,the flow health model is used to evaluate the hydrological health of Datong River Basin.In order to protect the ecosystem of Datong River,the main control measures are taken The main contents and conclusions are as follows:(1)The runoff of Garide and Gadatan station in Datong River Basin is increasing,and the runoff of Xiangtang station is decreasing,There was no obvious abrupt change point in the runoff of Garide and Gadatan,but there was a significant abrupt change in the annual runoff of Xiangtang station in 1996.Precipitation and temperature are both increasing,while the potential evapotranspiration in the upstream decreases,and the potential evapotranspiration in the middle and lower reaches increases.Precipitation,temperature and potential evapotranspiration have abrupt changes in 1989,1985 and 2002.Through the correlation analysis of runoff and meteorology,it is found that the influence of precipitation on runoff is more significant.(2)The Flow Health model is used to compare the flow data of Gadatan,Liancheng and Xiangtang from 2014 to 2017 with those before 1994.It is found that under the default threshold of the model,the flow health index(FH)score of the three control sections is not more than 0.8,indicating that there is a partial difference between the hydrological health of the river and the reference period in the test period(2014-2017).The(LF)low flow index score and(LM)Lowest monthly flow index score of the three hydrological stations in 2014 or 2015 were low,and the SFS score is basically 0.It shows that the runoff conditions of the basin are destroyed by the water conservancy projects,the flow in the river channel is reduced compared with the reference period,and the flow pattern has changed,which is unfavorable for the survival of many species.(3)we not only use different hydrological methods to calculate ecological flow,but also use Flow Health to model ecological flow,The Flow Health model is used to evaluate different ecological flow process,and the group with the highest FH score is selected as the best ecological flow scheme.Finally,the guarantee measures of ecological flow are put forward for Datong River,which provides reference for the subsequent management scheme of ecological flow.