Anthropogenic and natural disasters (e.g., wildfires, oil spills, mine spills, sewage treatment facilities) cause water quality disturbances in fluvial networks. These disturbances are highly unpredictable in space-time, with the potential to propagate through multiple stream orders and impact human and environmental health over days to years. Due to challenges in monitoring and studying these events, we need methods to strategize the deployment of rapid response research teams on demand. Rapid response research has the potential to close the gap in available water quality data and process understanding through time-sensitive data collection efforts. This manuscript presents a protocol that can guide researchers in preparing for and researching water quality disturbance events. We tested and refined the protocol by assessing the longitudinal propagation of water quality disturbances from the 2022 Hermit's Peak—Calf Canyon, NM, USA, the largest in the state's recorded history. Our rapid response research allowed us to collect high-resolution water quality data with semi-continuous sensors and synoptic grab sampling. The data collected have been used for traditional peer-reviewed publications and pragmatically to inform water utilities, restoration, and outreach programs.

Wildfires within the Southwest are expected to increase in frequency and severity, and are known to change terrestrial ecosystems, soil hydrophobicity, and a watershed's runoff response to precipitation. While wildfires' impact on a watershed and its localized effect on nearby stream reaches are well documented, what remains uncertain is how wildfire disturbances on water quality and stream metabolism propagate longitudinally through a fluvial system. To further our understanding of wildfire longitudinal impacts, we utilized five high-frequency in-situ sonde sites downstream of the Hermits Peak Calf Canyon (HPCC) wildfire, the largest wildfire in New Mexico state history, covering 192 km of the Gallinas Creek that included the Las Vegas, NM municipality and Santa Rosa Lake. Our results show a significant increase in turbidity (p-values < 0.05) at monitoring sites upstream of Santa Rosa Lake during periods of high discharge. During these periods, a significant reduction was observed in gross primary production at all monitoring sites upstream of Santa Rosa Lake (p-value < 0.05). Unlike the monitoring sites upstream of Santa Rosa Lake, the site downstream did not experience a significant change in turbidity (p-value = 0.12) and had a significant increase in gross primary production (p-values < 0.05). Stream metabolic fingerprints also indicated increased scouring, DOC, and sediments at sites upstream of Santa Rosa Lake, while the site downstream remained relatively stable. Our novel results demonstrate how a large-scale wildfire can cause localized impacts to water quality and stream metabolism and propagate through a fluvial system spanning multiple stream orders impacting downstream water quality and ecosystem services, and how a large lake was able to buffer those disturbances halting their propagation.

Wildfires generate hydro-geomorphological disturbances initiated by post-fire precipitation-runoff events. These disturbances are drivers of aquatic impairment over multiple months and years. While the impacts of wildfires on streams and rivers near burned areas have received increased attention in the last decades, it is still unclear how wildfire disturbances propagate longitudinally through fluvial networks. We deployed a rapid response team to install and maintain five high-frequency in-situ sondes to monitor water quality and stream metabolism changes over 190 km along the Gallinas Creek-Pecos River-Santa Rosa Lake fluvial network in response to the Hermit’s Peak - Calf Canyon (HPCC) wildfire, the largest in New Mexico’s recorded history. We assessed how far downstream water quality disturbances propagated along the fluvial network, the role of seasonality in that propagation, and the impact of lakes in mitigating further longitudinal propagation. Monitoring began a few days after the fire started in April 2022 and before any precipitation events had occurred. In the ten months post-fire, there were significant increases in turbidity and fDOM and reductions in gross primary production and ecosystem respiration at all monitoring sites upstream of Santa Rosa Lake. Stream metabolic fingerprints suggest increased scouring, DOC, nutrients, and suspended sediments at these sites. In contrast, the site downstream of Santa Rosa Lake did not have altered turbidity, gross primary production, or ecosystem respiration, and the metabolic fingerprints remained unchanged. These results suggest that Santa Rosa Lake, and associated water operations, buffered the propagation of wildfire disturbances ~180km downstream from the burn scar, resetting water quality parameters and metabolic activity for over ten months post-fire.

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