Research On The Evaluation Framework Of Hydropower Station Removal Of Tributaries In Yunnan Section Of Lancang River Basin

With the maturity of my country’s construction technology for high dams and large reservoirs,the construction of large-scale hydropower stations on the main stream has been completed successively,the economic benefits of small hydropower in the tributaries of the river basin have been declining,and the ecological impact has become increasingly prominent.Water-retaining structures such as reservoirs and dams have destroyed the continuity of the river.Fish,as the flagship species of the river ecosystem,must consider their habitats when developing.Based on a comprehensive review of foreign hydropower development,decommissioning and decommissioning experience,this study is based on the coordinated development of main and tributary streams,with the principle of tributary protection as the main principle,supplemented by the AHP,to establish a tributary hydropower decommissioning/decommissioning evaluation framework.Through the comprehensive assessment of the fish habitat restoration potential and the potential loss of the tributary after the removal of the dam,the hydropower station with good ecological benefits and small potential loss is evaluated,which is the protection of the aquatic ecosystem of the watershed in China and the protection of important fish germplasm resources.For example,to provide decisionmaking reference and suggestions.The main conclusions are as follows:（1）From a multi-disciplinary perspective,the research and evaluation of hydropower stations or reservoirs in the whole basin is rare.In response to this situation,this study proposes a set of reasonable,reliable and practical operability-based feasibility evaluation systems for dam demolition based on ecological needs,including the evaluation system "potential for fish habitat restoration after tributary demolition" and "dam demolition" Loss assessment index system,and the reliability was verified by the demolishing example of Jidu River Ⅳ power station.（2）The calculation results of this evaluation system show that the priority order of dam removal for the tributaries of the Yunnan section of the Lancang River Basin is as follows:Nanla River Jinfeng Hydropower Station,Weiyuan River Hydropower Station,Jidu RiverⅣ Hydropower Station,Heihui River Xucun Hydropower Station,Luozha River Ⅱhydropower station,Ⅶ hydropower station on the Liusha River,Ⅲ hydropower station on the Xi’er River,Ⅳ hydropower station on the Xi’er River,and the Nanguohe hydropower station.（3）This study assumes an extreme situation where all power stations on tributaries need to be demolished,and only the best ecological restoration effect is considered.In response to this situation,the weights of habitat restoration potential and dam demolition losses were adjusted to obtain the following rankings: Weiyuan River Hydropower Station,Nanla River Jinfeng Hydropower Station,Heihui River Xucun Hydropower Station,Luozha River II Hydropower Station,Jidu River Ⅳ hydropower station,Liusha River Ⅶ hydropower station,Xi’er River Ⅲ hydropower station,Xi’er River Ⅳhydropower station,Nanguohe hydropower station;correspondingly,only considering the least loss of dam demolition,the order is as follows: Nanguohe Hydropower Station,Xi’er River III Hydropower Station,Xi’er River IV Hydropower Station,Jidu River IV Hydropower Station,Liusha River Ⅶ Hydropower Station,Nanla River Jinfeng Hydropower Station,Luozha River II Hydropower Station,Heihui River Xucun Hydropower Station,Weiyuan River Hydroelectric power station.The two weights give completely different results,which provide a way of thinking for possible future dam removal assessments for specific purposes.