July 28, 2021

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Brandon Steets, Jared Ervin, and Avery Blackwell Coauthored a Paper on Sources of Low Level Human Fecal Markers in Recreational Waters of Two Santa Barbara, California Beaches in the Journal Water Research

Brandon Steets, P.E., (California) Jared Ervin, Ph.D., (California), and Avery Blackwell, P.E. (California), coauthored a paper entitled, "Sources of Low Level Human Fecal Markers in Recreational Waters of Two Santa Barbara, CA Beaches: Roles of WWTP Outfalls and Swimmers," which was published in the journal Water Research on June 20, 2021.

Dong Li was the lead author, and other coauthors were Laurie Van De Werfhorst, Jill L. S. Murray, Naresh Devarajan, and Patricia A Holden.

Brandon Steets is a Senior Principal Engineer based in California with more than 20 years of experience in National Pollutant Discharge Elimination System and Total Maximum Daily Load regulations, Clean Water Act litigation, water quality modelling, and monitoring, pollutant source investigation, and stormwater control planning and design.

Jared Ervin is a Senior Professional based in California with more than 10 years of experience focused on pollutant source tracking, surface and groundwater quality, advanced forensic tools, and environmental microbiology.

Avery Blackwell, Senior Engineer based in California, is a water resource engineer and project manager with pioneering water experience in California's public and private sectors including planning, monitoring, analysis, modeling, design, and compliance reporting of stormwater, water supply, and recycled water projects.
Water Research is an interdisciplinary journal with an applied edge, that publishes refereed, original research papers on all aspects of the science and technology of the anthropogenic water cycle, water quality, and its management worldwide.


Worldwide, fecal indicator bacteria (FIB) evidence coastal water contamination for which sources are unknown. Here, for two FIB-impacted Santa Barbara recreational beaches, hypothesized fecal sources were investigated over three dry seasons (summers) using nearly 2000 field samples of water (ocean, creek, groundwater), sand, sediments, effluent and fecal sources. In years 1 and 2, gull and dog feces were identified as the probable main FIB sources to surf zone waters, yet HF183 human fecal markers were consistently detected. Determining HF183 sources was therefore prioritized, via year 3 sub-studies. In lower watersheds, human and dog wastes were mobilized by small storms into creeks, but no storm drain outfalls or creeks discharged into surf zones. Beach area bathrooms, sewers, and a septic system were not sources: dye tracing discounted hydraulic connections, and shallow groundwater was uncontaminated. Sediments from coastal creeks and downstream scour ponds, nearshore marine sediments, and sands from inter- and supratidal zones contained neither HF183 nor pathogens. Two nearby wastewater treatment plant (WWTP) outfalls discharged HF183 into plumes that were either deep or distant with uncertain onshore transport. Regardless, local sources were evidenced, as surf zone HF183 detection rates mostly exceeded those offshore and nearshore (around boat anchorages). The presence of swimmers was associated with surf zone HF183, as swimmer counts (on weekdays, holidays, weekends, and during races) significantly correlated (p<0.05, n = 196) to HF183 detections. Besides comprehensively assessing all possible fecal sources, this study provides new explanations of chronic low-level human markers in recreational beach surf zones, suggesting likely lowest achievable HF183 thresholds.

More Information

Learn more about the article: Sources of Low Level Human Fecal Markers in Recreational Waters of Two Santa Barbara, CA Beaches: Roles of WWTP Outfalls and Swimmers - ScienceDirect
Learn more about the Water Resource Journal: Water Research | Journal | ScienceDirect.com
For consultation regarding water and natural resources contact Brandon Steets at This email address is being protected from spambots. You need JavaScript enabled to view it..
Learn more about Brandon at: https://www.geosyntec.com/people/brandon-steets
Learn more about Jared at: https://www.linkedin.com/in/jared-ervin-b648aa75/  
Learn more about Avery at: https://www.linkedin.com/in/averyblackwell/