The Ecological Risk Assessment Of The WuHan Urban Lake Wetland

Wetland is one of the three ecological systems in the world and it is widely distributed. It provided abundant of material resources for human, and it also has unique ecological function and environmental effect.Urban wetland refers to the wetland wich is distributed in the city. It is the important ecological infrastructure of city, and it provides water for the city. It provides perfect flood and draining waterlogging system for the city, and it also can adjust regional climate and reduce urban heat island effect.With the development of the urbanization and urban environment problem,wetland is being invaded and reconstructed.These causes some serious threat to the healthy of human beings.In order to scientifically estimate the risks of urban wetland, we can use ecological risk assessment to quantify the risk.The ecological risk assessment is to evaluate the risk which the ecological system and its components are suffering. It is currently used in water environment, regional ecological environment and soil pollution. The ecological risk assessment of research, which is introduced to urban wetland, has not much and in-depth. Lake is the main type wetland of Wuhan, which is compared to the "blood" and "eyes"of city.With the expansion of the construction in Wuhan, urban lakes suffered from serious damage. Many far lakes are gradually becoming urban lakes, and the effect of human activities on them will become more and more.Depend on the analysis of geographic environment, we know that the main risk of lakes comes from natural (flood disaster, drought disasters)and human interference (lake area of atrophy, water pollution).As the frequency and range of human activities become more and more, the risks which Wuhan lakes are going to face will be more and more. This paper follows the basic steps of ecological risk assessment.,and23lakes were selected, which are near or far to city. According to data collection and previous research achievements, the paper gives the risk of comprehensive evaluation and the paper also put forward the corresponding measures for wetland management and protection about Wuhan lakes. This paper has these conclutions: (1)These lakes turn out obvious changes in different urban region as their distance to the center of city change. The average level of Biodiversity in far Urban is more than central city and the average vulnerability index appears different trend.(2)Accroding to the data during2000—2010, the total area of the lakes is reducing and individual lakes area is increasing. This is because some lakes in central city are planed to be park and so on.(3) Accroding to the data in2010, the TP concentration of the lakes in center and the surburb is obviously lager than the lakes in the far city. The integrated value of TP, TN and CODMn concentration isdifferent in these three urban regions.(4)The Value of comprehensive ecological risk assessment can be ranked five grade.The higher grade means less risk. The most central city lakes belong to the area between grade1to3, and the far city lakes are in the area between grade4to5.