RAPID RESPONSE MONITORING OF THE HERMIT’S PEAK – CALF CANYON FIRE: WATER QUALITY IMPACTS

The Hermits Peak/Calf Canyon Fire is the largest wildfire in New Mexico’s recorded history. The massive, 341,735-acre, fire complex formed from the merging of two individual wildfires. The Hermits Peak Fire originated from a USFS prescribed burn on April 6, 2022. The Calf Canyon Fire erupted 13 days later on April 19^th from a pile burn holdover from January 2022. This incident occurred in the Pecos/Las Vegas Ranger District in Santa Fe National Forest, southern Sangre de Cristo Mountains. About 80,000 acres of the wildfire complex have been classified as severely burned by the Burned Area Emergency Response team. The Gallinas Watershed, whose axial stream is the primary water source for the City of Las Vegas, burned from its headwaters to town. This region is affected by the North American Monsoon System, bringing increased precipitation and intense thunderstorms between June 15 and September 30. Increased soil erosion, debris flows, flooding, and decreased water quality due to the fire and monsoonal rains pose health and safety risks to surrounding communities.

To understand the fire’s effect on water quality, our team deployed four EXO YSI 2 multiparameter sondes in the Gallinas River, measuring turbidity, pH, fDOM, chlorophyll A, conductivity, temperature, and dissolved oxygen every 15 minutes. These sondes were installed near USGS stream gauges. Grab water samples are taken every 2-3 weeks near sonde installations during sensor maintenance. Samples are analyzed for NH₄, NO₂, NO₃, PO₄, SO₄ and TON. Storm water samples are collected longitudinally, moving from within the fire perimeter to sites downstream outside the fire perimeter, to parse out the effect of runoff from burned areas on water quality during storm events. Repeat photography and in-stream assessments of the riparian zone, soils, and geomorphology at each site provides a holistic evaluation of water quality, which is directly tied to watershed system health. Headwater systems are vital sources of sediment, water, and nutrients critical to all downstream processes. Thus, it is imperative that we understand the impacts of the Hermits Peak/Calf Canyon fire on water quality, the basis of ecosystem health. Here, we present our initial findings of post wildfire water quality in the Gallinas River.