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In recent years, wildfires in the western United States have occurred with increasing frequency and scale. Climate change scenarios in California predict prolonged periods of droughts with even greater potential for conditions amenable to wildfires. The Sierra Nevada Mountains provide 70% of water resources in California, yet how wildfires will impact watershed‐scale hydrology is highly uncertain. In this work, we assess the impacts of wildfires perturbations on watershed hydrodynamics using a physically based integrated hydrologic model in a high performance‐computing framework. A representative Californian watershed, the Cosumnes River is used to demonstrate how post‐wildfire conditions impact the water and energy balance. Results from the high‐resolution model show counterintuitive feedbacks that occur following a wildfire and allow us to identify the regions most sensitive to wildfires conditions, as well as the hydrologic processes that are most affected. For example, while evapotranspiration generally decreases in the post‐fire simulations, some regions experience an increase due to changes in surface water runoff patterns in and near burn scars. Post‐fire conditions also yield greater winter snowpack and subsequently greater summer runoff as well as groundwater storage in the post‐fire simulations. Comparisons between dry and wet water years show that climate is the main factor controlling the timing at which some hydrologic processes occur (such as snow accumulation) while post‐wildfire changes to other metrics (such as streamflow) show seasonally dependent impacts primarily due to the timing of snowmelt, illustrative of the integrative nature of hydrologic processes across the Sierra Nevada‐Central Valley interface.
Cataloging Information
- climate extremes
- hydrologic modeling
- vegetation changes
- water management
- watershed dynamics
- wildfires