Coastal Pathogen TMDLs

Fecal indicator bacteria measurements are used to assess the presence of fecal waste material in a waterbody.  E. coli and enterococci bacteria are commonly measured as indicators of fecal waste.  The presence of fecal waste material is correlated with the potential presence of illness-causing pathogens, such as bacteria, viruses, or protozoa, which can cause illness either through direct contact or incidental water ingestion, impacting the contact recreation beneficial use (REC-1) or through ingestion of contaminated shellfish (SHELL).

The 2012 Section 303(d) list identifies thirteen (13) freshwater streams in the North Coast Region as impaired for the water contact recreation (REC-1) beneficial use due to exceedances of fecal indicator bacteria criterion.  The 2012 Section 303(d) list also identifies twelve (12) ocean beaches as impaired for SHELL beneficial use due to concentrations of fecal indicator bacteria.  Development of a Total Maximum Daily Load (TMDL) is required under Section 303 of the Clean Water Act to address waterbody-pollutant pairs that are identified on the 303(d) list of impaired waters.

The North Coast Regional Water Quality Control Board (Regional Water Board) approved by Resolution No. R1-2015-0012 the 2014 Triennial Review of the Water Quality Control Plan for the North Coast Region (Basin Plan), including a list of Basin Planning Project Priorities. TMDL development was identified as the Region’s number one planning priority, with the Ocean Beaches and Freshwater Streams Pathogen TMDL listed as priority #1c.

The development of a TMDL generally follows a common analytical process, including but not limited to: confirmation of impairment, assessment of pollutant sources and/or factors contributing to the impairment, and an assessment of the source reductions necessary to achieve water quality objectives and protect beneficial uses. Freshwater stream impairments are being investigated and assessed under the Coastal Streams Pathogen TMDL Project and the ocean beaches conditions are being addressed by the Ocean Beaches Pathogen TMDL Project. 

Analytes of Interest

The Regional Water Board collected water samples to assess the potential for recreational users of a given waterbody to come in contact with pathogens.  These water samples were measured for E. coli, total coliform, and enterococci fecal indicator bacteria. Bacteroides bacteria DNA markers are another useful measurement that was conducted on the collected water samples.  Bacteroides bacteria are animal host-specific, thereby allowing the assessment of the source of fecal waste that may be associated with elevated fecal indicator bacteria concentrations.  In the Coastal Streams Pathogen TMDL Project, animal host-specific bacterial source DNA markers may be used as a line of evidence when assessing the likely sources of fecal indicator bacteria in surface water samples.  Animal-host DNA markers measured were the overall DNA and animal host specific markers for humans, dogs, birds and ruminants (e.g., cows and deer).  Assessment of these data are underway.  Results will be posted once monitoring reports are final.

Coastal Streams Pathogen TMDL Project

Seven (7) of the freshwater streams listed as impaired due to pathogens on the 2012 Section 303(d) list are found within the Russian River Watershed and will be addressed by the Action Plan for the Russian River Watershed Pathogen TMDL, once adopted.  Of the six (6) remaining streams listed for pathogen impairment in the North Coast Region, one stream, Pudding Lagoon, is being evaluated together with Pudding Beach as part of the Ocean Beaches Pathogen TMDL Project.  The remaining five (5) streams, listed in the following table and depicted on attached Impaired Streams Location map, will be addressed in this Coastal Stream Pathogen TMDL Project.

Impaired Streams Monitoring Study

Five impaired streams were evaluated under the Coastal Stream Pathogen TMDL Project through monitoring of fecal indicator bacteria to verify water quality conditions and compare to water quality objectives.  The temporal variability of fecal indicator bacteria in these Section 303(d) listed streams was measured near the mouth of the catchments to determine water column concentrations under both wet and dry climatic conditions. Assessment of these data will provide the foundation for source reductions that may be needed to achieve water quality objectives, which fully support beneficial uses in these waters.  Bacteroides bacteria markers analyzed in conjunction with the fecal indicator bacteria samples collected from the impaired streams will also be used to assist staff’s evaluation of possible sources where elevated fecal indicator bacteria levels are detected.

Source Assessment Monitoring Study

The Porter-Cologne Water Quality Control Act directs Regional Water Boards to develop programs of implementation to achieve water quality objectives, which for the purposes of the TMDL Program generally are established as Action Plans, permits, or third party programs. As an example, many of the counties in the North Coast Region are developing Local Area Management Plans (LAMPs) as allowed under the statewide Water Quality Control Policy for Siting, Design, Operation, and Maintenance of Onsite Wastewater Treatment Systems (OWTS Policy), which may be sufficient as third party programs to address the OWTS source category in some or all of the listed waters.

To establish a pollutant control program or Action Plan capable of returning an impaired water to a trajectory of recovery, it is necessary to identify the sources of the pollutant. A pathogen source study endeavors to determine the degree to which known categories of fecal waste discharge (e.g., cattle pastures, septic systems, urban runoff, or wildlife areas) are in fact a significant source in a given waterbody. This is typically accomplished by collecting ambient water quality data immediately downstream of suspected source locations during both dry and wet periods. The suspected source locations sampled are listed in the following table and depicted on attached Source Sampling Locations Map.

Reference Streams Monitoring Study

In conjunction with Coastal Stream Pathogen Project, Regional Water Board staff collected data assessing FIB levels from sixteen (16) reference system stream catchments in the North Coast Region. A “reference system” is a stream catchment that is minimally impacted by human activities that could affect indicator bacteria levels in streams. The Regional Water Board collected samples to assesses bacteria levels from sixteen (16) reference stream catchments, which are listed in the table and depicted on the attached Reference Streams Locations Map.

Project Documents

The Coastal Streams Pathogen TMDL Project is intended to result in a plan for the assessment and control of fecal waste sources in the coastal streams listed as impaired for pathogens.  In accordance with the Health and Safety Code, any regulation that relies on science as its basis must be reviewed by a panel of scientific peers.  The results of the scientific work conducted under the Coastal Streams Pathogen TMDL Project will be posted on this webpage following successful completion of thescientific peer review process.

Project Milestones and Timeline

The development of a Coastal Stream Pathogen TMDL includes the following project milestones and timeline as follows:

Ocean Beaches Pathogen TMDL Project

Potential for human pathogen exposure has been linked to impairment of the shellfish consumption (SHELL) designated beneficial use, which is defined as water suitable for the collection of filter-feeding shellfish (e.g., clams oysters, and mussels, but not crabs) for human consumption. The 2012 Section 303(d) list identifies twelve (12) North Coast ocean beaches as impaired for the SHELL beneficial use due to the potential for pathogen exposure.

The North Coast Regional Water Quality Control Board conducted a monitoring study to assess pathogen levels and possible fecal waste sources at the ocean beaches listed as impaired in 2012, shown in the table below and depicted on the attached Impaired Beach Location Map. The project included analysis of E. coli, total coliform, and enterococci fecal indicator bacteria. Additionally, in order to assess potential waste sources, host specific bacterial markers for general, human, ruminant, dog, and birds were used to quantify the origins of the Bacteroides bacteria in each water sample.

Project Documents

The Ocean Beaches Pathogen TMDL Project is intended to result in a plan for the assessment and control of fecal waste sources in the coastal beaches listed as impaired for pathogens. In accordance with the Health and Safety Code, any regulation that relies on science as its basis must be reviewed by a panel of scientific peers. The results of the scientific work conducted under the Ocean Beaches Pathogen TMDL Project will be posted on this webpage following successful completion of the scientific peer review process.

Project Milestones and Timeline

The development of the Ocean Beaches Pathogen TMDL includes the following project milestones and timeline as follows: