Physics-based, integrated hydrologic modeling is a cornerstone of hydrology and water resources management. As high-performance computing advances and high-resolution observational data proliferate, new opportunities are emerging to enhance integrated hydrologic models. These advances enable more mechanistic process representations and more accurate predictions at spatial and temporal resolutions once unimaginable. This session focuses on applications using integrated hydrologic models to study complex hydrological processes across diverse ecosystems. We invite submissions examining processes routinely oversimplified in conventional models, including snow/glacier dynamics, disturbance (e.g., drought and wildfire) impacts, plant physiological functions, groundwater-surface water interactions, interplays between water-human systems. These insights will enable deeper process-based understanding, advance water resources management, and support broader societal resilience to increasingly complex environmental challenges.