Optimal design of water levels and multi-objective coordinated operation for basin-wide reservoir groups

The construction and operation of hydraulic and hydropower projects have altered the downstream hydrological regimes， resulting in significant changes in the spatiotemporal distribution of floods. Operation rules based on single-station natural observations and designed for individual reservoirs can no longer adapt to these dynamically evolving water and sediment conditions， leading to prominent conflicts between flood-season water releases and post-flood-season storage in many reservoirs. Against this backdrop， this study breaks through the traditional “single-reservoir design—static operation” paradigm by adopting a progressive approach of “planning and design—joint utilization—optimal operation.” It systematically reviews theories and methodologies for determining design floods in cascade reservoirs operation period， summarizes research approaches for joint design and complementary equivalent relationship of flood prevention storage in reservoir groups， and outlines models and solution techniques for multi-objective joint operation of cascade reservoirs. In addition， it identifies key scientific issues and critical technologies that require further research. Aiming at the efficient utilization of floodwater resources， the study recommends strengthening research and application in optimal design of water levels and multi-objective joint operation of basin-wide reservoir groups.