The Marshall Fire of December 2021 destroyed over 1,000 homes and businesses in Boulder County, Colorado, and overlapped much of the Coal Creek watershed. Our study monitored turbidity, nutrients, metals, alkalinity, conductivity, pH, and dissolved organic carbon in Coal Creek at burned and unburned, as well as wildland and urban sites from January 2022 to December 2023. We also analyzed benthic invertebrate and periphyton communities. Our results show significantly elevated levels of suspended solids, metals, and nutrients in the burned areas compared to the unburned reference site, with some metals exceeding EPA aquatic habitat criteria. Benthic invertebrate diversity and biological integrity was reduced in the burned urban reach compared to historical data. Additionally, virtual stakeholder meetings with decision makers and land managers were held throughout the study. A public data dashboard and ArcGIS story map were created to facilitate communication with stakeholders and the community. This study both provides findings to inform future mitigation after WUI fires and offers a model of community-engaged monitoring.

Magliozzi, L., Mansfeldt, C., McKnight, D., & Korak, J. A. (2023). Water Quality in Coal Creek Following the 2021 Marshall Fire. Natural Hazards Center Quick Response Report Series. University of Colorado Boulder. [Link] 

The devastating 2018 Camp Fire unleashed an urban firestorm in Paradise, California, resulting in the destruction of over 18,000 structures. While it is known that runoff from burned wildland areas contains ash, which can carry contaminants including metals into nearby watersheds, the effects of wildland urban interface (WUI) fires, such as the Camp Fire, on surface water quality remain poorly understood. Our research investigated the impacts of extensive urban burning on surface water quality in major local watersheds. Over a period from November 2018 to May 2019, nearly 150 samples were collected, comprising baseflow and stormflow from burned and unburned downstream watersheds with varying levels of urban development. Samples were analyzed for total and filter-passing metals, dissolved organic carbon, major anions, and  bulk water quality parameters, with a subset of samples analyzed for particle size distribution. Our findings reveal that ash and debris resulting from the Camp Fire contributed to elevated metal concentrations in downstream watersheds through stormwater runoff. Total concentrations of Al, Cu, Cd, Pb, and Zn exceeded EPA aquatic habitat acute criteria by up to 16-fold. Metals were found mostly associated with larger grain sizes (>0.45 µm), however Al, Cr, Fe, and Pb exhibited a significant colloidal phase (<0.45 µm). This study underscores the impact of wildland-urban interface fires on nearby affected watersheds, as evidenced by increased metal concentrations. These findings highlight the potential ecological consequences associated with such fires, emphasizing the importance of understanding and addressing the long-term effects of WUI fires on surface water quality.

Magliozzi L.J., Matiasek S.J., Alpers C.N., Korak J., McKnight D., Foster A.L., Ryan J.N., Roth D.A., Ku P., Tsui M.T.-K., Chow A.T., and Webster J.P. (2024), Wildland-urban interface wildfire increases metal contributions to stormwater runoff in Paradise, California. Environmental Science: Processes & Impacts. [Link]

This publication comprises Chapter 1 of PhD dissertation investigating impacts of wildland-urban interface fires on water quality and aquatic ecosystems.

• Designed and coded an R Shiny data dashboard allowing watershed groups, land managers, and decision makers to track water quality and benthic invertebrate monitoring data through dynamic visualizations.