New Mexico Geological Society Annual Spring Meeting — Abstracts

Richard P. McNeill^{1, 2}, Joseph P. Zebrowski¹, Anita Lavadie¹, Dr. Edward Martinez¹, and Dr. Sara Brown¹.

¹New Mexico Highlands University, P.O. Box 9000, Las Vegas, New Mexico 87701.

²Author of correspondence (juniper.botany@gmail.com)

High fuel loads and extremely dry conditions have led to previously unknown fire behavior and effects.  This study investigated the effect runoff from burned areas had on erosion and arroyo formation in the Cerro del Medio drainage within the Valles Caldera National Preserve, which was burned in the Las Conchas Fire in 2011.  This drainage is 139 hectares and 2.3 km long.  The majority of the drainage was categorized as a moderate or low severity fire.  24 hectares of the drainage were categorized as a high severity fire.  The first post-fire monsoon season was slightly above average with 129.79 mm of precipitation in September and October.  The first monsoon season’s runoff from the high severity patch has resulted in rapid geomorphic change.  An arroyo has formed that ranges up to 9.8 m wide and to 2.45 m deep.  Upon leaving the constrained drainage it has resulted in an alluvial fan deposit that is 24 hectares in two lobes with the longest lobe 1.9 km long.  Changing fire behavior has resulted in larger and more severe fires and this will likely result in rapid and extreme geomorphic changes on a landscape scale with a corresponding impact on human activities.