GEOLOGIC INPUT TO BURNED AREA EMERGENCY REHAB (BAER), A USDA FOREST SERVICE APPROACH

Wildfires burn over 1,000,000 acres per year on National Forests in the U.S. While a fire is still being controlled, interdisciplinary Burned Area Emergency Rehabilitation (BAER) Teams conduct rapid assessments of threats to life and property, potential watershed damage, threats to other resources, and risk to downstream “values”. Current and expected impacts are identified, a determination is made as to whether or not an “emergency” exists, and mitigation measures are recommended to minimize potential threats and damage before the next storms occur.

Possible geologic hazards, which may be exacerbated by the fire, include increased landsliding (debris flows and rock falls), flooding, accelerated erosion and increased sedimentation. Geologists trained in BAER assessment and experienced in land and resources management are able to characterize potential fire effects on fluvial and mass wasting processes, and recommend mitigation measures.

Pre-fire and post-fire slope stability conditions are determined using a geomorphic approach. Maps, photos, aerial reconnaissance and on-the-ground surveys are used to identify landforms that are susceptible to landslide processes, accelerated erosion and increased sediment delivery rates. Geologic, geomorphic, topographic and burn intensity maps help identify what areas, geologic materials and processes may have been affected, and identify “values at risk”. Aerial photos, both color and infrared, help identify vegetation, habitat and fluvial conditions before and (if available) after the burn. Aerial reconnaissance, usually by helicopter, gives an overview of the area and the impact created by the fire. On-the-ground reconnaissance allows verification of initial observations and interpretations, and mapping of discrete features and problem areas. Working in concert with other scientists and engineers, the geologist helps compile an inventory of “values at risk”, including homes and other structures, roads and bridges, riparian areas, dams and irrigation systems, critical forest resources, and other downstream improvements. Geologists play a key role in identifying potential risks and recommending measures to lower those risks and restore stability to the ecosystem.