A proposed delineation method for lake buffer zones in watersheds dominated by non-point source pollution

Although buffer zones around aquatic areas are a useful method for controlling non-point source pollution and restoring natural ecosystem services, proper delineation methods for lakes remain poorly defined, restricting their protection and the rational utilization of resources. As the width of lake buffer zones should be set to meet the area's functional targets and requirements, this study proposes a methodology for delineating these zones that includes critical source areas for non-point source pollution and ecologically sensitive areas. The proposed method was tested on Zhushan Bay, Lake Tai, China given its poor environmental condition and a renewed focus on mitigation by the local government. Data sources and relative processing methods include vector data on land use and hydrographic networks processed by ArcGIS, digital elevation model (DEM) data with 30 m resolution, soil and socioeconomic data from local governmental statistical yearbooks, NPS pollution load into lake obtained by literatures and field survey. The results showed that a minimum buffer range could be practically determined while meeting the requirements of both environmental protection and economic needs, providing a theoretical and practical basis for the improved delineation and management of lake buffer zones in watersheds dominated by non-point source pollution.