Based On The Basic Ecological Water Requirement's Ecological Water Research Of Fenhe Reservoir

Water is fundamental to the survival of mankind,with the continuous development of 21 st century's social economy and human's crazily exploit and utilize for the water resource,shortage of water resource is increasingly serious.Human energetically start to construct water conservancy during the several years.Water conservancy is the important wall of human's life and property security and social economic sustainable development.Although we enjoy the social and economical benefit that water conservancy bring,the unprecedented pressure is bear by river ecosystem.The balance between human's water using demand and maintain ecological system's water use demand is a important challenge of river management in 21 st century.After reservoir built,the flow of downstream river channel was changed,and the surrounding was influenced,because reservoir closed basic flow of non-flood season,and changed natural runoff process before the dam was built,so it made downstream river channel's water level sharply fall even cutoff.The article takes Fenhe reservoir downstream Lancun ? Erba and Yitang as example,and the main results as follows:(1)By analyzing Fenhe river's runoff features,in order to remit that the cutoff often appear in river and the ecological base flow can't be satisfied,The paper puts forward a calculation method of base flow towards northern rivers.According to natural annual runoff,one year is divided into three periods: wet season,normal level season and dry season,and calculate every period's percent of average flow in the same periods,and combines the least month's runoff within multiple months to calculate ecological water demand.The paper uses base River ecological waterresource of 1965-2013 year,and three methods: Tennant,dynamic calculation method and equal frequency method of base flow to calculate Fenhe River's three observation station: Lancun,Erba and Yitang.The calculations indicate that the new method is closer to dynamic change of ecological water demand and makes some sense to ecological management.(2)By matching measured value after building the dam,low flow's evolution model is built between adjacent sections,to compare with the ecological flow and measured flow to calculate filling water,and using adjacent sections' flow routing model,and calculate every month's ecological supplying water(m3/s),in order to meet every section's ecological base flow,so that the channel can be renewed as natural channel flow before the dam was built.The results are: ecological basic flow's annual average of Lancun is 1.4m3/s,ecological basic flow's annual average of Erba is 2.4m3/s,ecological basic flow's annual average of Yitang is 4.0 m3/s.(3)Establishing small flow's evolution process between neighbor sections,and calculating the ecological water compensation of every sections,in order to recover the natural flow situation before the dam was built.The results are: the ecological water compensation supplied by Fenhe reservoir form January to December are 0.23,0.22,0,0.21,0.21,0.20,0.11,0.13,0,0.04,0.22,0.22.