Spatial distribution pattern and zoning management strategies of water-level-fluctuation zone in Danjiangkou Reservoir

Mastering the distribution characteristics of different land use types and slopes in the water-level-fluctuation zone can not only provide essential baseline data for the ecological protection and management of the Danjiangkou Reservoir′s water-level-fluctuation zone but also offer a scientific basis for formulating differentiated protection and utilization measures for this area. Based on Sentinel-2 multispectral remote sensing images with a spatial resolution of 10 m, the spatial distribution and land use characteristics of the water-level-fluctuation zone in the Danjiangkou Reservoir were interpreted. The results indicate that: ① The area of the water-level-fluctuation zone within the elevation range of 150.00~170.00 m in the Danjiangkou Reservoir is 378.82 km², with areas of 216.00 km² and 162.82 km² in the 150.00~160.00 m and 160.00~170.00 m elevation ranges, respectively. Xichuan County, Yunyang District, and Danjiangkou City contain the largest areas of the water-level-fluctuation zone. ② Within the 150.00~170.00 m elevation range, the most extensive land use type is grassland (42.33%), followed by cropland (32.26%) and sand/mudflat (24.65%), while forestland (0.27%) and construction land (0.49%) occupy relatively small areas. Grassland is primarily distributed in Danjiangkou City (83.24 km²), Xichuan County (35.72 km²), and Yunyang District (33.03 km²). Cropland is mainly concentrated in Xichuan County (115.04 km²) and Yunyang District (6.33 km²). ③ Approximately 97.09% of the water-level-fluctuation zone area is classified as an ecologically sensitive zone. Within this area, 362.7 km² falls within drinking water source protection zones, and 153.6 km² is located within the Danjiang Wetland National Nature Reserve. ④ It is recommended to implement refined zoning, classification, and differentiated management strategies, along with establishing a dynamic adjustment mechanism. Scientific delineation of preservation zones, ecological restoration areas, and comprehensive treatment zones should be prioritized. The primary focus should be on preservation and ecological restoration, supplemented by engineering measures, to enhance scientific and technological innovation support capabilities and maintain the ecological functions of the water-level-fluctuation zone.