The Relationship Between The Protection Rate Of Ecological Base Flow And Ecological Risk Response In The Weihe River Basin

Water is the source of life,water is important in ecological system,the river is an important part of the earth system,is the important path of hydrologic cycle,the global the transmission of the material energy and transportation plays an important role,the wei river as the largest tributary of the Yellow River,the mother,plays an important role of population growth and diversification of production activities to the water pressure as a result of the rapid expansion of the industry,the northwest economic rise,followed by pollutants caused the wei river basin create many problems.Human's excessive development of river basin water resources,river ecological base flow can't guarantee,the upstream water loss and soil erosion,middle water pollution,the downstream water loss and soil erosion,river basin water ecological risks,not only affect the health of the ecological environment,the more the crisis of human health and the survival so in view of the ecological baseflow and ecological risk response relationship were studied.Tennant method is used to calculate the ecological base flow of 12 sections of Wei River,Jing River and Beiluo River.The ecological base flow of Wei River system in flood season accounts for the majority.The ecological base flow of each section shows an increasing trend from January to May,and a decreasing trend from September to December.The ecological base flow of Wei River system and Jing River has an obvious increasing trend from upstream to downstream in each month.Under the condition of meeting the minimum requirement of river ecological environment,the ecological base discharge of Yangjiaping,Yuluping and Zhangjiashan in Jinghe River system are 2.91 m3/s,1.48m3/s and 6.43 m3/s,respectively;the Jing River system Zhangjiashan is located in the lower reaches of the Jing River,near the intersection with the main stream of the Weihe River.From January to June,there was no significant difference in the size of the ecological base flow in the three sections,but in July,the ecological base flow in Zhangjiashan increased sharply.From July to September,the ecological base flow in Zhangjiashan,Yangjiaping and Yuluoping were large to small,respectively.The maximum value of ecological base flow in Zhangjiashan was 13.57 m3/s in July and the minimum value was 0.28 m3/s in January.The maximum value of ecological base flow in Yangjiaping and Yuluoping were 7.47 m3/s and 4.34 m3/s in August,respectively,and the minimum ecological base flow was 1.15 m3/s and 0.39 m3/s in January,respectively.Beiluo River system Liujiahe,Jiaokouhe,Zhuangtou ecological base flow is 0.76 m3/s,3.87m3/s,10.59 m3/s.With the average monthly flow in 2013 as the current flow,there is a situation that the guarantee rate of sample points for many months is less than 1,which can not meet the basic ecological needs.Through the analysis of the Cr of 12 section of Wei River basin sediment Pb zinc As Hg Cd 6 kinds of heavy metal content,study the concentration of pollution and ecological risk results show that the concentration of heavy metals in space there are differences in the sediment Cr Pb zinc concentrat:ion of Hg content of soil background values are higher than the province,including wei fort Cr Pb concentration of the background value of 1,26 times and 3.28 times respectively,due to metal smelting papermaking textile technology and discharge of waste water producedIn 12 points,the most severe and Pb and Hg pollution ecological risk level of the worst point is still a fort wei jia to dilute contaminated sediments,eliminate the influence of large sediment artificial sources of loess plateau,determine the heavy metal pollution of weihe river basin in the lower levels of five metals pollution by order for the zinc>Hg>Cr>Pb>As,potential ecological risk level from high to low position Hg>Pb>As>Cr>zinc potential ecological risk assessment results of weihe river basin highlights many problems,corresponding measures should be taken to strengthen management.12 section for ecological security of base flow and potential ecological risk,and carries on the correlation analysis,found the two at the 0.05 level was significantly negative correlation,and there is a logarithmic relationship under a certain error,relation to Kif=-4.115In(RI)+20.576 according to this relation,this paper measured data that are in the 12 section of weihe river basin in the future study of ecological security of baseflow and potential ecological risk,can be used as auxiliary reference.