Historical landscape condition study of discontinued river corridor based on satellite image data analysis

The historical landscape condition of discontinued river before discontinued flow is one of the core research fields of river ecological restoration and an important historical reference for the ecological restoration of discontinued river corridor. In this paper, the landscape condition of Yongding River, a discontinued river in northern China, is analyzed before its cut-off. Through the early KEYHOLE satellite high-definition image data interpretation analysis, the landscape type map of the river corridor before its cut-off was drawn. The overall winding degree (1.27) and the overall horizontal and vertical structure of the river before its cut-off were determined. In addition, the area proportion of the key landscape types in river corridor, such as channel, mid-channel bar and floodplain, is 12.82%, 8.8% and 16.29% respectively, and the morphological characteristics and distribution of the above key landscape types in each section of the river can be determined by quantitative analysis. On this basis, the landscape pattern index analysis method can be used to analyze and calculate the overall landscape pattern of the river corridor before cut-off. Combined with relevant historical hydrological data, the historical state of the river before its cut-off can be restored to a certain extent. These results are of great support to the channel ecological restoration, floodplain ecological reconstruction and riverbank ecological restoration.