Environmental Impact Assessment Design for Integrated River Basin Planning Under “Three Lines and One Permit” Policy

[Objective] The "Three Lines and One Permit" (TLOP) eco-environmental zoning management system plays a crucial role in the development of ecological civilization in China. However, its in-depth integration with Environmental Impact Assessment (EIA) for integrated river basin planning remains underdeveloped. To address the prominent conflict between ecological conservation and development in strategic EIA of river basin planning, this study proposes a TLOP-based EIA design framework to ensure the implementation of zoning management requirements. [Methods] A comprehensive EIA framework integrating “planning analysis, environmental assessment, and admittance list” was established. TLOP-based formulation methods for river basins were proposed, including four-category ecological zoning, quantifiable environmental quality baselines, and dynamic control of resource utilization ceilings, which were validated through a case study of the Ganjiang River Basin. [Results] In Ganjiang River Basin, priority conservation waters spanning 200.46 km and key conservation waters covering 592.99 km were delineated. 36 cross-sections for water quality monitoring were established with a Chemical Oxygen Demand (COD) emission limit set at 201 800 t/a. Five conflicting projects, including the Maodian Cascade, were rejected. The ecological flow management was optimized to ensure that the total planned water use (12.94 billion m3) did not exceed the upper limit indicator. [Conclusion] The study achieves innovative dynamic coupling between TLOP and strategic EIA. The developed eco-environmental admittance list for river basins provides precise control of development intensity, offering a replicable paradigm for cross-scale environmental management and facilitating the coordination between high-quality basin development and ecological conservation.