The Research On Poyang Lake Wetland Ecological Water Requirement

This paper based on the study of ecological water requirement on the basis of theory and method,upon poyang lake wetland remote sensing image, and collection of poyang lake hydrological data, the poyang lake water is divided into rainy season and dry season, in view of the ecological groundwater level method and the natural material method, Determine the minimum ecological groundwater level lake 7.16m to 8.39 m, Suitable scope of ecological groundwater level 12.31 m to 13.41 m; In remote sensing image interpretation. The vegetation index NDⅥthreshold value system, Sure stimate poyang lake wetland ecological water requirement in the central area of 993.53 km2 and ecological range for activities range 2689.8 km2;According to the wetland ecological hydrological structure model, Based on the water balance method is applied to calculate the central poyang lake on ecological water requirement in the relative, Appropriate area of ecological water requirement on relative;Based on the function method to calculate poyang lake ecological water requirement in the central area of 2.662 billion m3, Appropriate area of ecological water requirement in the 6.003 billion m3.The main steps of the following:(1) The ecological groundwater level method and the natural water level method is used to determine the minimum poyang lake ecological groundwater level 7.16 m to 8.39 m and appropriate ecological groundwater level 12.31 m to 13.41 m.(2) The TM remote sensing image classification interpretation, with ERDAS to image NDVI calculation, again to image NDⅥfor threshold classification, combined with the ecological groundwater level determine appropriate central district and poyang lake area of estimation range, were 993.53 km2 and 2689.8 km2.(3) According to the wetland ecological hydrological structure model, based on the water balance method is applied to calculate the central and Appropriate area of poyang lake on ecological water requirement monthly in the relative.(4) Based on wet function calculate poyang lake wetland ecological water requirement in the central area of 2.662 billion m3, and appropriate inflection of the 6.003 billion m3.