MONITORING THE IMPACTS OF THE 2022 HERMITS PEAK/CALF CANYON FIRE ON THE UPPER PECOS RIVER WATER QUALITY

The Upper Pecos Watershed (UPW), part of the larger Rio Grande Basin, extends from the headwaters of the Pecos River in the Sangre de Cristo Mountains to its confluences with Cow Creek and El Rito. The Upper Pecos River supports recreation, agriculture, cattle grazing, tourism, and other uses. It is one of the most ecologically diverse and culturally significant areas of New Mexico. The UPW, along with other regional watersheds, was impacted by the 2022 Hermits Peak/Calf Canyon Fire, the largest wildfire in New Mexico’s history (>340,000 acres). Approximately 40,150 acres burned in the UPW, 34% of which were classified by the USFS Burned Area Emergency Response (BAER) team as high burn severity. Such classification raises concerns for post-fire erosion, including the potential for subsequent sediment delivery, stream flows and debris flow. Our team has been collecting weekly in-the-field physical-chemical parameters (electrical conductivity, temperature, dissolved oxygen, and pH) using a YSI 556 Multi Probe and grab water samples for turbidity analysis using a Hach TL2300 turbidimeter throughout the Summer 2022 to assess the after-effects of the wildfire. These data are being compared to water quality data collected by the team in Summer 2020 and Summer 2021 to determine if and how much the water quality parameters are departing from baseline values. Since the start of the monsoon rains (mid-June), the ash and floating debris were observed along with rising turbidity values in exceedance of the NMAC 20.6.4.900 water quality threshold (> 10.00 NTU). All other measured water quality parameters are meeting water quality standards (WQS) for the Upper Pecos River’s high-quality cold-water designation (NMAC 20.6.2). We will continue to monitor the Upper Pecos River’s water quality, as water health in the system sets the basis for the rest of ecosystem health. Upon conclusion of Summer 2022 data collection, we will graphically and statistically analyze the interrelationship between the studied attributes and the effect of stream flow on all of the water quality variables. We will report our findings at the annual GSA meeting.