The California State Water Board issued guidance on November 12, although dated October 20, 2020, regarding industrial stormwater dischargers in areas identified in an emergency proclamation that are impacted by wildfires. Specifically, for industrial facilities damaged and/or negatively impacted by wildfires within the following counties: Shasta, Napa, Sonoma, Siskiyou, Fresno, Madera, Mariposa, San Bernardino, San Diego, Del Norte, Los Angeles, and Mendocino.

As an industrial discharger in California, industrial facilities that have not successfully filed a No Exposure Certification, are required to sample the stormwater that runs off their site during a Qualified Storm Event at least four (4) times per year, two in the first half of the reporting year (July – December), and two in the second half of the reporting year (January – June). If a facility is in a compliance group, the sampling requirements are once in the first half, and once in the second half. Further, if a facility is a Level 1 or 2 discharger, the facility may wish to sample more frequently to return to Baseline.

But it hasn’t rained all summer and we had wildfires in the area…

If the ash and firefighting materials have fallen on your buildings, roofs, structures, and paved areas in a significant amount, you may be able to make an argument for wildfire impact if the sampling results exceed an applicable NAL, NEL, or TMDL. Specifically, that the results are not representative of your industrial processes; it’s not you – part of what is in that discharge came from aerial deposition.

The ability to successfully argue that your stormwater was impacted by wildfires is not automatic or absolutely certain – you have to take action.

The following are requirements for consideration:  

• If you are located in one of the above-listed counties, you may be able to make the argument.

• Collect documentation that shows impacts by wildfires – photos, inspections – BEFORE the sampling event and during the sampling event. This could include photos of roofs, awnings, tree or shrub leaves, and other surfaces that may have collected wildfire deposition. Take a photo and collect a sample, if you are able.

• Identify the stormwater samples that were impacted by wildfire, and report this information when uploading to SMARTS.

• Report the basis for why the sample results are not representative of your industrial operations.

• The notice provides a number of example factors that could be used for documentation of wildfire impact.

• Document any identified factors in your Storm Water Sampling Event Observation form, which you need to fill out every time you collect a sample.

Submit as a non-qualifying event:

The notice says that if you determine that any sample results are not representative of your industrial activities, you may submit the results and analysis in SMARTS as a non-qualifying event. These events will not be included in the NAL exceedance calculation. If you choose to do this, we recommend working with an experienced stormwater consultant to help make sure that you have all your documentation and it is solid.

Please contact us or call (800) 508-8034 to speak with any of our QISPs if you have any questions or need additional information.

Blog Author

Jodie Crandell, QISP, QEP, TOR
Senior Project Manager
KERAMIDA Inc.

Contact Jodie at jcrandell@keramida.com.