Channel morphology and large wood control postfire debris-flow erosion and deposition
Links
- More information: Publisher Index Page (via DOI)
- Open Access Version: Publisher Index Page
- Download citation as: RIS | Dublin Core
Abstract
Runoff-generated debris flows are a known response to wildfire, and accurately predicting the volume of these debris flows is important for estimating the magnitude of downstream hazards. Prior data collection efforts have focused on debris-flow volume measurements at catchment outlets, but few studies have considered how erosion and deposition modulate the volume of sediment arriving at catchment outlets. This study takes advantage of a high-resolution dataset to document the factors that control the total debris-flow volume reaching the catchment outlet during a fatal postfire debris flow. Using pre- and post-event airborne lidar, satellite imagery and field mapping, we found that a postfire debris flow in the Black Hollow catchment in northern Colorado eroded 136,000 ± 30,000 m3 and redeposited 27,000 ± 7,500 m3 in the main channel. Most of the in-channel deposition (52% by volume) occurred where a confined channel reach transitioned to an unconfined channel reach downstream, allowing the flow to widen and deposit material. Wood jams played multiple roles in the debris-flow dynamics, both nucleating deposition (25% of the deposit volume was stored behind wood jams) and exacerbating erosion (50% of the total erosion occurred downstream from a wood dam break). The remaining deposition occurred due to spatial changes in channel slope as well as deposition observed at newly formed channel bars. Using these data in this study, we identified topographic and vegetation metrics that can be used (pre-event) to anticipate where deposition may occur in channels prior to a debris flow.
Suggested Citation
Rengers, F.K., Stoker, J.M., Kostelnik, J., Kean, J.W., Wohl, E.E., Barnhart, K.R., and Guido, L.E., 2026, Channel morphology and large wood control postfire debris-flow erosion and deposition: Earth Surface Processes and Landforms, v. 51, no. 4, e70287, 13 p., https://doi.org/10.1002/esp.70287.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Channel morphology and large wood control postfire debris-flow erosion and deposition |
| Series title | Earth Surface Processes and Landforms |
| DOI | 10.1002/esp.70287 |
| Volume | 51 |
| Issue | 4 |
| Publication Date | April 12, 2026 |
| Year Published | 2026 |
| Language | English |
| Publisher | Wiley |
| Contributing office(s) | Geologic Hazards Science Center - Landslides / Earthquake Geology |
| Description | e70287, 13 p. |
| Country | United States |
| State | Colorado |
| Other Geospatial | Black Hollow |