Changes in hydrologic regimes—altered flow timing, flooding, and drought—are reshaping water quality across rivers, floodplains, groundwater, and connected land–water systems. These changes influence nutrient and contaminant transport, sediment dynamics, and biogeochemical processing, with cascading effects on ecosystem function, human health, and societal risk. Communities, planners, and water managers face growing challenges interpreting and responding to these impacts under non-stationary conditions, where scientific uncertainty, governance constraints, and community knowledge intersect.

This session invites inter- and transdisciplinary contributions examining hydrologic regime change, water quality, and societal outcomes across scales. We welcome quantitative and qualitative research on water quality responses to floods, droughts, and flow variability; land–water interactions mediated by hydrologic connectivity; and implications for disaster risk reduction, public health, and management. Contributions may span empirical and modeling studies, socio-hydrologic analyses, and applied case studies integrating water quality science with policy questions, community-based research, and experiential knowledge in decision-making.

• B - Biogeosciences
• GH - GeoHealth
• NH - Natural Hazards
• SY - Science and Society