Graduate Student/Water Resources Engineer San Diego State University/Michael Baker International
Disclosure: Disclosure information not submitted.
Wildfires can have significant impacts on watersheds, affecting hydrology, geomorphology, water quality, and urban infrastructure. Wildfires are increasing in number and severity in California, which has the potential to impact waterways not only within the burned area, but also further downstream and into coastal waters. Surface water quality after wildfires in areas with anthropogenic influences have documented increases in various metal pollutants such as lead, mercury, copper, and zinc, as well as nutrients, total suspended solids (TSS), and sediment. However, there is very little research on bacteria, specifically Escherichia coli (E. coli), following wildfires. This research focuses on the 2018 Woolsey Fire in Malibu, California, to understand the seasonal trends of pollutant levels for E. coli, nitrogen, phosphorus, TSS, and copper, as well as analyze the impacts of other factors such as land use, discharge, precipitation, and septic tank locations on contaminant loading. Water quality data from monitoring stations three years (2016-2018) prior to the Woolsey Fire and one year after the fire (2018-2019) for three watersheds (the Santa Monica Bay Watershed, the Malibu Creek Watershed, and the Upper Santa Clara River Watershed) were compared. The Santa Monica Bay (5 monitoring stations) and Malibu Creek (14 monitoring stations) watersheds were directly impacted by the Woolsey Fire and approximately half of the stations were located within a burned drainage area. The Upper Santa Clara River watershed (12 monitoring stations) was unaffected by the fire and is used as a control watershed. Preliminary results show that the Woolsey Fire contributed to substantial increases of bacteria levels during multiple storms following the fire compared to pre-fire conditions. This work has implications for managing coastal watersheds after fire and mitigating the impacts of contaminated waterways.
Learn about the implications of wildfires on surface water quality
Learn about potential sources of pollutants that enter surface water
Learn about potential measures and tactics for watershed management and mitigation to address wildfires