Altered streamflow dynamics following Hurricane Michael and their linkage to forest damage in South Carolina, USA

Hurricanes are a major hydrological disturbance in the southern United States (US), yet their impacts on different streamflow components and their linkage to forest damage across different forest types remain poorly understood. This study examines the impacts of Hurricane Michael (2018) on streamflow dynamics across multiple watersheds ( n = 21) in South Carolina, a state located in the southeastern US. Streamflow was separated into its components using a digital filter, and recovery times were estimated using anomaly-based metrics. In addition, we analyzed whether variations in forest damage among forest types are associated with changes in streamflow components across watersheds. Our results show a statistically significant difference in recovery behavior between the two components. Quickflow recovered rapidly (median of 8 days), and baseflow exhibited a substantially delayed recovery (median of 114 days) post-hurricane. On average, the post-hurricane quickflow slope increased by 3.5 times relative to pre-hurricane conditions, compared to 2.5 times for baseflow, with greater variability observed in quickflow (SD = 1.69 vs. 1.21). Finally, watersheds with significant changes in quickflow and baseflow also had significantly higher forest damage in the Oak-Gum-Cypress and Elm-Ash-Cottonwood forests ( p < 0.05). This study shows that forest cover, particularly bottomland forests, plays a critical role in buffering streamflow responses. The findings of this research will help water resources managers to understand watershed-specific streamflow responses following hurricanes and other severe storms.