FIRE SEVERITY IN THE LAS CONCHAS REGION OF NORTHERN NEW MEXICO

Overview Methods Results and Future Work

During the summer of 2011, a tree fell on a powerline which ignited a fire that lasted several weeks in the Las Conchas region of New Mexico near Santa Fe. It was the largest forest fire in New Mexico’s recorded history, impacting the Santa Fe National Forest, Bandelier National Monument, Santa Clara Pueblo, and the Valles Caldera National Preserve. This fire severely altered 624 square kilometers of land in the Jemez mountains, including several archeological sites, miles of recreational trails and numerous surrounding watersheds (Bixby et. al., 2015). The area affected by this fire is shown to the left in red. To the left is a map showing the fire severity classes of the Las Conchas fire determined by the US Forest Service, using remote sensing to determine the loss of organic matter in the soil.

Arguably, water quality plays one of the most important roles post-fire in determining management strategies for public health and many of these issues stem from the impacts of wildfires on soil (Bixby et. al., 2015). Some of the major concerns include increased sediment loads and the associated nutrients, increased turbidity and a decrease in primary productivity as a result, and flooding or erosion of the impacted watershed. Despite recent efforts, much more research is needed to extend our understanding of the connection between wildfires and water quality. The map to the right shows the network of streams that flows though the Las Conchas region. This network was created using data from the USGS, a 10x10m DEM, and the hydrology toolset within ArcGIS. It was determined that the total area within each severity class does not correlate with the total length of stream impacted similarly by that severity class. This lays a foundation to understand the difference between area affected by fire and the effects on the watershed. Using the information from this study, further research can be done to determine the effects on water quality that involve variables like sediment load and nutrient analysis of the stream network.

References

Bixby, Rebecca J., et al. "Fire effects on aquatic ecosystems: an assessment of the current state of the science." Freshwater Science 34.4 (2015): 1340-1350.

Keeley, Jon E. "Fire intensity, fire severity and burn severity: a brief review and suggested usage." International Journal of Wildland Fire 18.1 (2009): 116-126.

Reale, Justin K., et al. "The effects of catastrophic wildfire on water quality along a river continuum." Freshwater Science34.4 (2015): 1426-1442.