Measurement of Dongting Lake Area Based on Visual Interpretation of Polders

摘要

How many square kilometers is the area of Dongting Lake (DTL)? This question has been discussed for many years. For the most periphery borderline of the water just close to the first and secondary dikes around the lake during flood period, therefore, these dikes were chosen as research targets. Visual interpretation by using of ETM+ images acquired in September 2001 to get information of these targets closest to the water surface. However, in inner region of these dikes surrounded, some islands and key dikes cannot be submerged by flood should be removed in DTL area measurement, and the result the area is 2713.855 km~2. Compare with previous researches, which show differences and limitations in different methods. The new area value obtained from this study is the largest water surface can reach in flood season of DTL without any dike broken, which can provide a scientific decision-making basis for sustainable development of DTL wetlands.