The Fire Effects Study

Upper Los Angeles River and Rio Hondo Watersheds

What is the Fire Effects Study?

A first-of-its kind regional scientific study led by the Upper Los Angeles River (ULAR) and Rio Hondo Watershed Management Groups (WMGs) and the San Gabriel Valley Council of Governments (SGVCOG) identifying wildfire impacts on water quality. This study is funded by Los Angeles County’s Safe, Clean Water (SCW) program and is designed to uphold the goals of the SCW program. Key features of the study area are water quality monitoring and modeling to characterize pollutant loading, collaboration with the Regional Water Quality Control Board (RWQCB), and coordination with research institutions to support project design and peer review.

Map showing the area of the Fire Effects Study
Safe Clean Water Program logo

Funded by the Safe, Clean Water Program.
Access additional study reports here.

Why is the Fire Effects Study important?

Previous studies have documented an increase in the frequency and intensity of wildfires due to climate change and human activities, as well as an increase in pollutants (i.e., metals and nutrients) following wildfires. While some wildfire water quality information is available, data gaps exist for the ULAR and Rio Hondo Watersheds. Furthermore, numerous water bodies within these watershed are impaired by metals and nutrients and are subject to Metals and Nutrients Total Maximum Daily Load (TMDLs) requirements. The Fire Study is an opportunity to address data gaps and inform management strategies that contribute to the attainment of water quality requirements and potentially provide regulatory relief.

Special studies demonstrate an increase of pollutants in storm water after wildfires

Project Example:
Effects of California Wildfires on Storm Water

Chart showing results of Fire Effects Study

What are the goals of the Fire Effects Study?

Improve water quality and contribute to attainment of water quality requirements

Leverage other funding sources to maximize SCW program goals

Encourage innovation and adoption of new technologies and practices

Invest in scientific research

How does the Fire Effects Study help watershed managers?

The Fire Effects Study will provide data to answer key questions including how wildfires impact contaminant loading, how metals and nutrients concentrations compare between burned and non-burned areas, how runoff influences downstream receiving waters, and what factors influence the persistence of these impacts. Answering these questions provides ULAR and Rio Hondo stormwater managers with data to help select water quality treatment best management (BMP) projects and evaluate BMP performance based on wildfire conditions therefore, supporting more informed decisions that better protect water quality and help attain regulatory compliance.

Chart showing the dataflow of the Fire Effects Study

This study also initiates discussions with regulatory agencies on meeting compliance targets and potential regulatory relief from impending TMDLs, while providing information that other watershed management agencies can reference or use to model their own local wildfire study.

In Partnership with the following:

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Council for Watershed Health Logo
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