Basic ecological flow compensation benefit of Longyangxia and Liujiaxia cascade reservoirs for Yellow River

In order to improve the computation of ecological compensation benefit of reservoir regulation,first,the conception and connotation of basic ecological flow compensation(BEFC) benefits of reservoirs is given in this paper.Second,the conception and calculation formula of river ecological mark are put forward for measuring the ecological benefit of river flow.Based on this,a method and procedure are brought forward for quantitative calculation of BEFC benefits of cascade reservoirs.Finally,taking Longyangxia and Liujlaxla cascade reservoirs on Yellow River as a study case of demonstration,the calculation result shows that in the no-flood seasons of 2003 these two reservoirs provided BEFC benefits of 17.77 and 28.94 billions ecological marks to Lanzhou station and Huayuankou station,respectively.Of the total 46.71 billions,31.88 billions came from Longyangxia reservoir,and the other 14.83 billions from Liujiaxia reservoir.The quantitative calculation of BEFC benefits for Yellow River in this paper indicates the importance of paying a great attention to the study of river BEFC benefits.