Post-Wildfire Sediment Yield in a Sierra Nevada Watershed

The research, conducted in the aftermath of the 221,835-acre (89,773-hectare) Caldor Fire, focused on a heavily logged, forested watershed in California’s western Sierra Nevada, and provides findings needed to understand and anticipate post-fire sediment risks.

Sediment Increases Threaten Water Resources and Infrastructure

Wildfires leave hillslopes vulnerable to erosion, often leading to increased sediment transport in streams. This sediment surge can fill up water-storage space in reservoirs, damage infrastructure, and disrupt water supplies, particularly in regions where fire activity is intensifying due to climate change. Understanding the extent and timing of sediment delivery is crucial for resource managers assessing risks to ecosystems, water supplies, and downstream infrastructure.

Post-Fire Sediment Monitoring

Over two years following the Caldor Fire, scientists measured sediment accumulation in a reservoir downstream of the burn area. During the first year, sediment delivery was minimal, largely due to reduced rainfall and limited disturbances within the burned watershed. However, the second year saw a sharp increase in sediment deposition, driven by higher rainfall and ground disturbances caused by post-fire logging activities.