Post-fire modelling points to higher water availability in California’s Feather River watershed
The story at a glance
A water-balance model estimates that streamflow and soil moisture increased in parts of California’s upper Feather River watershed after several major fires. The results describe a possible hydrological effect, not a conservation benefit. 1
The estimates come with important qualifications: water availability varies from year to year, and the study reports declining precipitation and snowpack. Post-fire flooding, erosion and debris flows can also create risks for water supplies. 15
What you need to know
- The North Complex Fire in 2020 and the Dixie and Sugar fires in 2021 burned more than half of the upper Feather River watershed, the area examined in the USGS study. 1
- At Feather River at Oroville, the model estimated annual streamflow increases of 22% in water year 2022, 32% in 2023 and 16% in 2024. Estimated summer baseflow increases were smaller: 5%, 12% and 2%, respectively. 1
- Estimated seasonal soil-moisture increases reached up to 34%, depending on location. The study also reports declines in annual precipitation and mid- to high-elevation snowpack in the watershed between 1981 and 2020. 1
- The 2023 water year was exceptionally wet, and the study cautions that year-to-year variability complicates interpretation of the streamflow estimates. A separate model study of the basin also estimated post-fire increases, while identifying substantial uncertainty in its fire-affected simulations. 12
- More water in the model does not mean that wildfire reliably improves water supply. Post-fire flooding, erosion and debris flows can affect reservoirs, water quality and water treatment, while broader research finds that river-flow responses differ among regions. 45
Why this matters
For watershed and forest practitioners, the findings show why fire-related changes in water quantity need to be considered alongside climate trends and other post-fire risks. The modelled increases are specific to this watershed and do not establish a dependable supply gain. 15
What happens next
The key test is whether the modelled changes match sustained field observations across the watershed. Further evidence will also be needed to understand how vegetation recovery, future fires, precipitation and snowpack trends affect the size and duration of any water gains, and how these interact with water-quality and habitat risks. 125
What we know
- The USGS study used a physically based water-balance model to estimate post-fire changes in streamflow and soil moisture in the upper Feather River watershed. 1
- A separate modelling study of the Feather River Basin also estimated increases in streamflow and soil moisture after fire, but reported large uncertainties in its fire-affected simulations. 2
- Research across western US watersheds supports the possibility that fire-related vegetation loss can reduce plant water use and raise streamflow in some places. Broader analysis finds that responses vary between water-resource regions. 134
What we don't know
- It remains unclear how closely the modelled streamflow and soil-moisture changes match sustained field observations across the watershed. 12
- The studies do not establish how long the estimated water gains will last or whether they translate into reliable, usable water supply. 124
- How vegetation recovery, future fire, precipitation and snowpack trends will affect the size and duration of any gains remains unresolved. 12
- The reporting identifies unresolved trade-offs between water quantity and post-fire risks to water quality, aquatic habitats and downstream communities. 5
Read the reporting
This WildNews briefing synthesises and summarises reporting from the sources below. WildNews did not produce the original reporting. Learn more about how we use AI
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