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.