Han et al. (2026) Wildfire-induced disruptions to evapotranspiration, runoff, and water-balance closure across California's water supply watersheds

Identification

• Journal: Hydrology and earth system sciences
• Year: 2026
• Date: 2026-07-15
• Authors: Ziying Han, Han Guo, Michael L. Goulden, Roger C. Bales
• DOI: 10.5194/hess-30-4367-2026

Research Groups

• Department of Civil and Environmental Engineering, University of California, Berkeley, CA, USA
• Sierra Nevada Research Institute, University of California, Merced, CA, USA
• Department of Earth System Science, University of California, Irvine, Irvine, CA, USA

Short Summary

This study investigates the impact of wildfires on evapotranspiration (ET), runoff, and water-balance closure across major water-supply basins in California. The research reveals that high-severity fires consistently suppress ET by 100-250 mm in the first post-fire year, with recovery influenced by moisture availability and disturbance recurrence.

Objective

• Investigate how wildfires reshape evapotranspiration (ET), runoff, and basin-scale water balance across California's critical water-supply watersheds.
• Quantify the impact of wildfires on ET reduction and recovery.
• Evaluate the influence of wildfires on basin outflow patterns.
• Diagnose wildfire-induced disruption to basin-scale water balance.

Study Configuration

• Spatial Scale: Watersheds in northern California, including the Trinity, Upper Sacramento, McCloud, Pit, and Feather watersheds.
• Temporal Scale: Four decades (1985-2023) of satellite-derived evapotranspiration (ET), precipitation (P), full natural flow (FNF) records, and spatially explicit fire-perimeter data.

Methodology and Data

• Models used: Landsat-based empirical model for ET estimation.
• Data sources: Satellite-derived ET products from the Center for Ecosystem Climate Solutions (CECS), gridded daily precipitation from PRISM climate dataset, monthly full natural flow (FNF) estimates from the California Data Exchange Center (CDEC).

Main Results

• Wildfires caused substantial reductions in ET across burned areas, ranging from 40 to 440 mm yr−1.
• ET gradually increased in subsequent years as vegetation recovered.
• The magnitude of first-year ET reduction increased with the fraction of high-severity burn area.

Contributions

• This study provides a comprehensive understanding of the impact of wildfires on evapotranspiration (ET), runoff, and water-balance closure across major water-supply basins in California.
• The research highlights the importance of considering fire history, disturbance intensity, and ET-recovery patterns in hydrologic models and reservoir operations.

Funding

• This study was funded by the University of California, Berkeley, CA, USA.

Citation

@article{Han2026Wildfireinduced,
  author = {Han, Ziying and Guo, Han and Goulden, Michael L. and Bales, Roger C.},
  title = {Wildfire-induced disruptions to evapotranspiration, runoff, and water-balance closure across California's water supply watersheds},
  journal = {Hydrology and earth system sciences},
  year = {2026},
  doi = {10.5194/hess-30-4367-2026},
  url = {https://doi.org/10.5194/hess-30-4367-2026}
}