A call for strategic water-quality monitoring to advance assessment and prediction of wildfire impacts on water supplies

Abstract

Wildfires pose a risk to water supplies in the western U.S. and many other parts of the world, due to the potential for degradation of water quality. However, a lack of adequate data hinders prediction and assessment of post-wildfire impacts and recovery. The dearth of such data is related to lack of funding for monitoring extreme events and the challenge of measuring the outsized hydrologic and erosive response after wildfire. Assessment and prediction of post-wildfire surface water quality would be strengthened by the strategic monitoring of key parameters, and the selection of sampling locations based on the following criteria: (1) streamgage with pre-wildfire data; (2) ability to install equipment that can measure water quality at high temporal resolution, with a focus on storm sampling; (3) minimum of 10% drainage area burned at moderate to high severity; (4) lack of major water management; (5) high-frequency precipitation; and (6) availability of pre-wildfire water-quality data and (or) water-quality data from a comparable unburned basin. Water-quality data focused on parameters that are critical to human and (or) ecosystem health, relevant to water-treatment processes and drinking-water quality, and (or) inform the role of precipitation and discharge on flow paths and water quality are most useful. We discuss strategic post-wildfire water-quality monitoring and identify opportunities for advancing assessment and prediction. Improved estimates of the magnitude, timing, and duration of post-wildfire effects on water quality would aid the water resources community prepare for and mitigate against impacts to water supplies.

Persistent and lagged effects of fire on stream solutes linked to intermittent precipitation in arid lands

“…Changes in water quality may have far-reaching effects on ecological, agricultural, and municipal functions (Paul et al 2022;Williams et al 2022;Raoelison et al 2023), particularly if they appear or persist on timescales longer than those for which data are available. The results of this study and others Murphy et al 2023;Raoelison et al 2023) highlight the critical need for additional water quality data collection over extended periods that encompass both pre-and post-fire conditions. Developing a quantitative understanding of the interactions between climate, hydrology, and fire at the terrestrial-aquatic boundary will improve our capacity to predict consequences for stream water quality and recovery of ecosystem function.…”

A Conceptual Framework to Assess Post‐Wildfire Water Quality: State of the Science and Knowledge Gaps

“…Murphy et al (2023) outlined a targeted post-fire water quality sampling strategy to improve assessment and risk prediction. Examples of identified data gaps in many post-fire sampling plans include linking factors such as precipitation intensity to changes in water quality and hydrology (Murphy et al, 2023). Our framework defines the relation among these factors and stressors, providing a path for water resource managers to target specific explanatory or response variables within the scope of their projected goals.…”

Longitudinal propagation of aquatic disturbances from the largest wildfire recorded in New Mexico, USA

“…Impacts to ecosystem services: Besides altering water quality, carbon and nutrient cycling, and stream metabolism fluxes, the propagation of wildfire disturbances affects ecosystem services. For example, increases in turbidity overburdens water purification in water treatment plants, disrupting day-to-day activities in affected locations 42 . During the HPCC fire, high turbidity and organics in Gallinas Creek forced the City of Las Vegas, NM, to halt its use as the primary source of potable water.…”

“…Since current fire models consistently predict that the prevalence of wildfire and associated damage will continue to increase due to anthropogenic climate change and forest management practices 27,[38][39][40][41] , we need to quantify and predict the propagation of wildfire disturbances through fluvial networks. This knowledge gap hinders our ability to mitigate wildfire impacts on water quality and protect vital aquatic ecosystem services 42 .…”