Rainfall-Runoff Generation Patterns and Key Influencing Factors in the Plain of the Taihu Lake Basin, China

The study investigates the hydrological cycle mechanisms in the Taihu Basin plain to support the development of next-generation, physically-based hydrological models for plain regions. Comprehensive monitoring at two experimental sites captured key hydrometeorological variables, including rainfall, evaporation, groundwater depth, soil moisture, and outlet flow. Analysis of runoff processes revealed that saturation-excess runoff dominates the rainfall-runoff mechanism, while infiltration-excess and mixed runoff models occur under specific conditions. Initial soil moisture and groundwater depth significantly influence runoff coefficients, with groundwater depth exhibiting a parabolic relationship. Furthermore, despite the relatively flat terrain, micro-topography markedly impacts runoff pathways, convergence times, and water distribution. Simulations using existing models highlighted the critical roles of micro-topography and runoff patterns in shaping hydrological responses, offering theoretical support for advancing refined hydrological models and improving water resource management in plain areas.