Research On Ecological Water Requirements For Rivers And Lakes

The ecological water requirements theory is the core question to deal with the relationship of human being and ecosystem. On the base of collecting much correlative research fruits, some calculation methods, which are suit to the situation of Chinese riverbeds and lakes , are researched to calculate the amount of ecological water requirements in the paper.Firstly, through collecting lots of research production of ecological water requirements, characteristics of these methods are analyzed. These ecological water requirements calculation methods are sorted.Secondly, basic meaning of ecological water requirements is researched. The formation, structure, functions and characters are analysed. The relationship of river flow and instream ecosystem is studied. From the angle of water values, the hoped ecological water requirements is defined. From the angle of non-biologic environment, the minimum environmental water requirements is defined. Based on Shelford patience law, the minimum ecological water requirements and suitable ecological water requirements are defined. The characters of time and space and threshold are studied. The ecological water requirements are sorted. The quantization method of three class ecological water requirements are studied.Thirdly, instream ecological water requirements calculation methods are researched. Based on the study of flow and river topography subsystem, and river width is regarded as indicator of the subsystem characters, the flow and river topography analyse method is put forward in the paper to calculate the minimum environmental water requirements. Based on the study of flow, river topography and biology subsystem , fish is regarded as bioindicator of the instream ecosystem, the method of biology space minimum requirements is put forward in the paper to calculate minimum ecological water requirements. The estimating method of suitable ecological water requirements is put forward using fish ovipostional velocity of flow .Fourthly, lake ecological water requirements are researched. It is put forward that lake ecological water requirements are composed of lake inlet, lake area and lake outlet ecological water requirements. The functions of these lake ecological water requirements are researched. Three kinds of the lake lowest ecological water level calculation methods are put forward. The first one is the lake natural water level data statistics method. The second one is the lake morphology analytic approach. The third one is the lowest space demand method of biology. The model of ecological waterrequirements in lake are set up. From the angle of relation of lake water and lake ecological evolvement, the lake ecological evolvement history method is studied for calculating lake suitable ecological water requirements.Fifthly, in line with these three methods , minimum and comfortable ecological water requirements and minimum environmental water requirements are calculated in YONG River and GUO River. Some characteristics for the minimum ecological flow are found in these two rivers. A conclusion is gained that the minimum ecological flow in proportion to average nature flows shows the proportion of downriver is less than that of upriver. The river width of the minimum ecological flow in proportion to the downriver width of average nature river width of is lager than that of upriver reach. It is showed that the risk of less rivers is larger than that of bigger ones . One experience formula of minimum ecological flow for YONG River and GUO River is set up. The minimum ecological water requirements calculation model and the suitable ecological water requirements calculation model are set up in NANSI lake for situation of data of NANSI lake. Ecological water requirements in NANSI lake are calculated in the paper.