Monitoring of Post-Fire Bedload Transport Using Hydrophone in a Small Burnt Catchment, South Korea

• Published in: Forests Vol. 13; no. 11; p. 1774
• Main Authors: Lee, Ki-Hwan, Uchida, Taro, Seo, Jun-Pyo
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.11.2022
• Subjects: Bed load; Catchments; clockwise and counterclockwise hysteresis; Environmental aspects; Environmental monitoring; Environmental restoration; Environmental risk; Flood management; Floods; Forest & brush fires; Ground cover; Hydrophone; Hydrophones; Landslides; Methods; Monitoring; mountain stream; Mountains; Particle size; Precipitation; Rain; Rainstorms; Rivers; Seasons; sediment supply condition; Sediment transport; Sediments; Soil erosion; Storm damage; surrogate monitoring technique; Transport properties; Watersheds; wildfire effect; Wildfires; South Korea; Alps
• ISSN: 1999-4907; 1999-4907
• DOI: 10.3390/f13111774

Understanding the properties of wildfire-disrupted catchments is crucial for managing river floods and landslide risks. Using a hydrophone, we investigated the changes in sediment supply conditions in small mountainous catchments (30.8 ha) in southern Korea for 6 years (March 2014–December 2019). Bedload transport rates mostly increased in burned catchments 1–2 years post-wildfire (early post-fire sediment regime) but decreased 3 years post-wildfire owing to the coverage of burned slopes (late post-fire sediment regime). Landslides triggered 5 years post-wildfire increased the bedload transport rates by approximately one order of magnitude (post-landslide sediment regime). Although sediment activity decreased in wildfire-disturbed catchments after recovery of the ground-cover layer 1–3 years post-fire, thy increased during events such as landslides. Furthermore, even in undisturbed mountainous catchments (139.7 ha), bedload transport rates increased after intense rainstorm events (≥100.0 mm), with this change lasting for approximately 2 years. Our observations showed that the forest restoration after a wildfire should be planned and implemented from a min- to long-term perspective. In addition, during rainstorms, the relationship between flow and bedload transport showed large variability even in undisturbed catchments. Furthermore, surrogate monitoring using a hydrophone was useful in understanding the changes in bedload transport characteristics according to various supply conditions of the catchment.