Study On Ecological Water Requirementof Wetland In Yellow River Delta Natural Conservation Area

The Yellow River Delta National conservation area ,locating at the estuary ofboth the current and the old flow path of the Yellow River, is the newborn deltamuddy wetland with most typicality, vulnerability and research，of China . Since the1970s, the serious degradation of Yellow River Delta National conservation areawetland is directly related to the die-off of the freshwater. The Yellow River is themain source of freshwater, so the change of inflow of the Yellow River flow path ofLijin Station following areas directly affects the status of conservation area’s wetlandecosystem . The text takes the Yellow River Delta National conservation area wetlandas research purpose. Studies the types of different functional in the conseversationand wetland ecological water requirements (minimum, medium and maximum)underthe different development levels. Then make a status quo analysis of the currentcondition of the conservation area’s wetland and raise some reference guidance for therational allocation of the Yellow River water resources and the implementation ofrelevant project . The thesis includes the following contents:1.Discourses the background and significance of the ecological waterrequirements studies. And divide the ecological requirements both domestic andabroad according to characteristics of different periods into four research stages。Besides briefly summarizes the the research status of the Yellow River Delta wetland .2.Briefly overview the location,extent and the natural and geographicalconditions of the Yellow River Delta (geology,geomorphology,climate,vegetation andaves).In addition, analyses the construction of water resources in the conservation areawetland, summarizes the three main aspects such as the coming water and sediment ofthe Yellow River water resources situation, the influence of the wetland,produced bycutoff and the effect of wetland restoration produced by the water-sediment regulationproject.3.With the ecological observations,the interpreted remote sensing pictures ,combined with historical data collection,site survey and the previous research results ,the text divides the reserved wetlands into three categories：terrestrial wetland ecologywater requirement,river wetland ecology water requirement and shallow waterwetland ecology water requirement. According to respective ecological functions ofland wetlands, rivers wetland,and shallow water wetland, use the functional approachto divide the types of the wetland ecological water requirement into vegetation andnon-vegetation evapotranspiration water requirement,soil water requirement,rechargegroundwater water requirement and river ecological base flow water requirement,river self-purification water requirement , river sediment water requirement , preventingcoastal erosion water requirement , shallow ecology environment water requirement.Then builds the method models mainly using the hydrology method, water balanceprinciples and so on.4. Wetland in different stages of development corresponds to different ecologicaldemand, the water requirement of health evolution of wetland is in certain thresholdvalue range. The minimum water requirement refers to the minimum requirementneeded to maintain its own existence , once the water declines, wetland will be broken,degraded, and even disappear. Suitable water requirement refers to the requirementrestores and maintains a stable situation which can not be destroyed, and satisfies thecurrent situation for vegetation growth and animal living and multiplying. Themaximum water requirement refers to the amount at which level the wetlandecological functions are fulfilled sufficiently to make the regional vegetation at acomparative satisfactory degree, species and quantities of animals reach the bestrequirement amount which can be carried. At the meantime, the ecological system isin good and stable state. Normalization of each function together promote the wetlandrestoration area into health evolution of land wetland ecological system, river wetlandsystem, shallow sea environment protection system, vegetation and precious birdsplay a good indication role in the development of ecological function.5.Make a reliability analysis of the calculation results,comparative study on theYellow River ecological water requirements and the Yellow River runoff of Lijin. andcomparative study on different types of ecological water requirements. Currently thecurrent runoff of the Yellow River meets the minimum wetlands ecology waterrequirement and have a gap to reach the medium wetlands ecology water requirement.The wetland ecosystem is at the unstable degenerate boundary stage. The wetlandrestoration projects are needed to promote the sustainable development. Finallyaccording to status of the Yellow River runoff and the wetland ecosystem, put forwardsome proposals for the wetlands sustainable development and the management of thewetland ecological restoration.