Santa Barbara Beaches MST Study - Case Study on MST at High Use Beaches
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Elevated concentrations of fecal indicator bacteria (FIB) in receiving waters throughout California raise serious concerns for the protection of human health, and public agencies have spent millions of dollars implementing structural BMPs to address this problem.

With the future price tag in the billions of dollars for the installation and maintenance of adequate structural BMPs to bring public agencies into compliance with FIB TMDLs, Microbial Source Tracking (MST) offers a cost-effective option to identify the highest priority bacteria sources (i.e., contributions from humans) and implement targeted source control and abatement BMPs.

The California Microbial Source Identification Manual is recognized by California regulators and USEPA as the leading guidance on MST. The Manual, co-authored by UCSB's Dr. Trish Holden with contribution from Geosyntec's Dr. Jared Ervin, is the result of the Source Identification Protocol Project (SIPP). For the SIPP, Dr. Ervin led one of four field demonstrations to test DNA markers in an urban watershed, resulting in a case study demonstrating successful identification and remedy of anthropogenic sources. During these studies, human markers were detected at three other Santa Barbara beaches, which Geosyntec and UCSB researchers used as the basis for a successful Clean Beaches Initiative research grant application. The objective of this project is to determine sources of human and/or other anthropogenic wastes at these beaches and prescribe targeted abatement remedies.

Geosyntec and UCSB, with feedback from local stakeholders, developed and implemented a comprehensive MST Monitoring Plan and Quality Assurance Project Plan to: (a) identify sources of human and non-human waste to Leadbetter Beach, East Beach at Sycamore Creek, and Goleta Beach and Slough, and (b) support local agencies in identification of management actions for improving beach water quality. The Plan was designed based on a hypothesis-driven and tiered investigation approaches. The Plan includes flexible milestones and offramps such that identified sources can be addressed immediately rather than waiting until study completion.

This presentation will discuss the implementation, findings, and conclusions stemming from the past three years of executing the MST Monitoring Plan, as well as provide practical connections and take-away guidance to assist MS4 managers throughout California. Nearly a dozen hypotheses (e.g., background sources, MS4 and sewer contributions, leaking or failing septic, WWTP effluent) were investigated (and conclusively eliminated) to identify sources of human bacteria persistently detected at these important local beaches. Through field investigations, numerous beach, slough, creek, storm drain outfalls, sewers, and boat areas were evaluated for human fecal contamination and other non-human sources. Where human waste markers were detected, they were tracked to their points of origin in combination with analytical and field investigation tools (e.g., CCTV, visual observations, sewer dye testing, groundwater sampling, etc.). Recent results directed investigations towards hypothesis testing of bather shedding and open defecation (e.g., by homeless persons) as potential sources. This State funded collaborative effort between Geosyntec and UCSB demonstrates a state of the science MST practical investigation to achieve meaningful public health benefits and to support the compliance efforts of permitted public agencies, which include both the MS4 agencies and local sanitation districts.

The audience will be invited to participate through a Q&A session to discuss guidance for developing and implementing a hypothesis driven MST investigation specific to their watershed conditions. This presentation is directly related to the conference's theme as it describes how MST has been utilized to "connects the drops" between elevated FIB concentrations and the identification and abatement of human bacteria sources.

Publication Summary

  • Geosyntec Authors: Brandon Steets, Avery Blackwell, Jared Ervin
  • Title: California Stormwater Quality Association (CASQA)
  • Event or Publication: Event
  • Practice Areas: Stormwater and Integrated Water Resource Management
  • Citation: Riverside Convention Center
  • Date: 2:30 - 3:00 p.m. on Wednesday, October 17th
  • Location: Riverside, California