Legacy Effects of Forest Changes and Channel Modification on Flood Behavior in the Ozark Highlands, Missouri

ABSTRACT Forested watersheds regulate flood response through canopy interception, infiltration, and soil–channel interactions, but combined effects of forest conversion, legacy disturbance, and channel modification on headwater hydrology are poorly understood. This study examines impacts of historical forest disturbance and channel modification on flood behavior in Big Barren Creek (48 km 2 ), a headwater watershed in southeastern Ozark Highlands, Missouri. 1880–1920 intensive logging removed > 90% native shortleaf pine, shifting to hardwood‐dominated forests with soil degradation and channel modifications. Using HEC‐HMS, early‐spring storm flood response (minimal interception, high risk) was simulated under present‐day, pre‐settlement, and post‐disturbance conditions. Pine‐to‐hardwood conversion reduced interception ~50%, increasing peak discharge 24%, runoff 32%, and shortening lag time 7% versus pre‐settlement. Channel modifications increased flashiness, raising peaks +9% and advancing time‐to‐peak 45 min. Post‐disturbance forests produced ~20% less runoff than present‐day, but degraded soils increased peak discharge 17% and prolonged duration 8%. Restoring 100% shortleaf pine nearly reproduced pre‐settlement hydrology; complete hardwood conversion had little additional impact on current conditions. Vegetation composition, soil condition, and channel morphology are primary controls on headwater flood response; integrated forest and channel management can enhance watershed resilience.