Wetland Resources Monitoring And Investigation In Hangzhou City Based On Remote Sensing Technology

There are very plentiful wetland resourses in Hangzhou city, especially the famous xixi wetlands and the west lake etc. They are not only composing a part of the landscape of the city but having important ecological function and promoting the development of economy. However, owing to man's unreasonable utilization, the wetlands area in Hangzhou city were quickly reduced, the ecological system had been seriously influenced and menaced. So it is emergent to pretect wetland resources. For reasonable exploitation and protection the wetlands resourses, it is important to investigate and monitor the wetlands resources in Hangzhou city.Possessing the advantages of macroscopic information, real time, periodicity and integrity, remote sensing provides the possibility for monitoring wetlands quickly, objectively and precisely. At present, application remote sensing technology to study wetlands has been a hotspot of wetlands research. The main satellite data adopted in the research of wetlands were TM or ETM. Little work has been done to the application of higher resolution SPOT-5 satellite image on wetlands investigation.Wetlands dynamic change and investigation in Hangzhou city supported by remote sensing, GIS and GPS, using SPOT-5 multispectral and TM/ETM data was studied in this paper, and the methods of wetlands classification by remote sensing were discussed. The main conclusion of this study is summed up as follows:(1) During the year of 1991 to 2003, the area of wetlands decreased, it decreased 8135.64 hectare during these 12 years and the rate of decreasing is 25.01%.Among wetlands, the area of bulrush swamp decreased most seriously because of the rapid development of the city. It decreased 625. 77 hectare during these 12 years and the rate of decreasing is 45. 35%. The main decreasing area of bulrush swamp was xixi wetland in the situation of Jiangcun. During the year of 1994 to 1999, the area of bulrush swamp decreased fast. After the year of 1999, the area of bulrush swamp decreased less because of wetlands protection.The area of paddy field also decreased fast. It decreased 8761. 41 hectare during...