Objective definition of discharge thresholds for post-fire debris flows

Hui Tang, Luke McGuire, Ann Youberg

Research output: Contribution to journalConference articlepeer-review

Abstract

Runoff-generated debris flows are a common post-fire hazard in the western United States and a growing number of regions around the world. As wildfire continues to emerge across a broader range of geographic regions and plant communities, there is an increasing need for generalizable methods to predict post-fire debris-flow initiation. The prediction of post-fire debris flow during intense rainstorms has traditionally relied upon empirical rainfall thresholds. Rainfall intensity-duration thresholds are often developed based on rainfall data and the hydrologic response to those rainstorms. They are most applicable to the specific regions where data are collected. Here, we present a new predictive approach that utilises processes-based models with fundamental physics and machine learning methods to estimate discharge thresholds for runoff-generated debris-flow initiation in four recently burned areas in the western United States. We assess the performance of the objectively defined discharge threshold-based predictions for post-fire debris-flow initiation from our hybrid framework, which utilises debris-flow timing within rainstorms, physically based numerical simulations of runoff, and the support vector machines method. The proposed thresholds have a good balance between true and false predictions for debris flow and floods. Importantly, our method permits the direct estimation of rainfall intensity-duration thresholds for areas where post-fire debris flow observations are limited.

Original languageEnglish (US)
Article number03029
JournalE3S Web of Conferences
Volume415
DOIs
StatePublished - Aug 18 2023
Event8th International Conference on Debris Flow Hazard Mitigation, DFHM 2023 - Torino, Italy
Duration: Jun 26 2023Jun 29 2023

ASJC Scopus subject areas

  • General Environmental Science
  • General Energy
  • General Earth and Planetary Sciences

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