THE EFFECTS OF THE LAS CONCHAS FIRE, NEW MEXICO: FLASH FLOODS AND ENHANCED RUNOFF

The Las Conchas Fire is recorded as the largest wildfire in New Mexico state history burning approximately 156,000 acres (63,000 ha). About 16,000 of those acres (6,500 ha) were in the Santa Clara Pueblo, representing 45% of the pueblo’s watershed. The loss of vegetation and soil structure due to the fire has caused an increased risk of potentially dangerous flashfloods within and downstream of the burn area. Multiple government agencies have focused their efforts on the burn sites and stabilizing these areas. However, the downstream impacts of the fire can also be severe. For example, Cochiti Pueblo and Tent Rocks National Monument are in immediate danger of flash floods. They are both located in Peralta Canyon, and infrastructure is being threatened by the downstream floods including a new road that was paved in 2010. This study was conducted to understand and predict impacts of the wildfire on downstream systems. The focus area was Peralta Canyon because of a major flood that occurred in August 2011 following the fire. This flood was recorded as having a flow of approximately 6,500 ft³/second (185 m³/s). The study involves documenting last year’s flood and the immediate stabilization efforts using georeferenced inventory. As well as, estimation of stream discharge based on high water observations. There was a collaboration effort between a few government agencies and the University of New Mexico that helped merge information. Future work will focus on predicting long-term channel response including flash-flood potential.