Difference between revisions of "TMDL for Fecal Coliform for the Lower Salinas River Watershed, Monterey County, California"

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(Watershed Description)
(Watershed Description)
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== Watershed Description ==
 
== Watershed Description ==
The project area is bounded http://ecoviz.csumb.edu/wiki/skins/common/images/button_hr.pngby the Gabilan Range to the east, the Sierra de Salinas range to the west, and the Monterey Bay to the northwest. [[Image:TMDL_project_area.JPG|thumb|TMDL Project Area]] The TMDL study is defined by the lower 400 square miles of the Lower Salinas Valley and includes two major watersheds, the [[The Gabilan / Reclamation Ditch Watershed| Reclamation Canal]] and [[The Lower Salinas Watershed| Lower Salinas River]]. The [[The Gabilan / Reclamation Ditch Watershed| Reclamation Canal]] watershed drains into [[The Old Salinas River Channel| the Old Salinas River]] and includes Tembladero Slough and its tributaries.  
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The project area is bounded http://ecoviz.csumb.edu/wiki/skins/common/images/button_hr.pngby the Gabilan Range to the east, the Sierra de Salinas range to the west, and the Monterey Bay to the northwest. [[Image:TMDL_project_area.JPG|thumb|TMDL Project Area]] The TMDL study is defined by the lower 400 square miles of the Lower Salinas Valley and includes two major watersheds, the [[The Gabilan / Reclamation Ditch Watershed| Reclamation Canal]] and [[The Lower Salinas Watershed| Lower Salinas River]].
  
 
Surface water sources include precipitation, releases from reservoirs, groundwater, and return flows from agricultural irrigation.  Mean annual precipitation in the project area ranges from approximately 13 to 16 inches per year with the majority of precipitation occurring between November and April.  
 
Surface water sources include precipitation, releases from reservoirs, groundwater, and return flows from agricultural irrigation.  Mean annual precipitation in the project area ranges from approximately 13 to 16 inches per year with the majority of precipitation occurring between November and April.  

Revision as of 10:01, 25 March 2010

This page is a a summary of the Regional Water Quality Control Board Central Coast Region report on Total Maximum Daily Load for Fecal Coliform for the Lower Salinas River Watershed, Monterey County, California (RWQCB, 2009)[1] by the Spring '10 ENVS 560/L Watershed Systems class at CSUMB.

Project Definition

The California Regional Water Quality Control Board for the Central Coast Region (CCRWQCB), in collaboration with the Environmental Protection Agency (EPA), established the Total Maximum Daily Load (TMDL) for Fecal Coliform for the Lower Salinas River Watershed in Monterey County, California. The final TMDL report was promulgated for the CCRWQCB meeting on March 10, 2010.

The TMDL report addresses the impairment of the Lower Salinas River and several of its tributaries as a result of increased fecal coliform concentrations. The fecal coliform group of bacteria (otherwise known as 'fecal indicator bacteria' (FIB)) are used to help identify water body contamination from pathogens. If fecal coliform concentrations exceed certain criteria, the water body may be listed as impaired in accordance with Section 303(d) of the Clean Water Act. The project area includes the following impaired water bodies:

  • Lower Salinas River (from Gonzales downstream to the Salinas River Lagoon)
  • Old Salinas River
  • Tembladero Slough
  • Salinas Reclamation Canal
  • Gabilan Creek
  • Alisal Creek
  • Natividad Creek
  • Santa Rita Creek
  • Quail Creek
  • Chualar Creek
  • Towne Creek

Each water body is used for specific purposes (or beneficial uses). When waters fail to meet the minimum quality standards required for those designated uses, a TMDL must be established. The waterbodies of the Lower Salinas watershed are used for a variety of purposes including, but not limited to: groundwater recharge, wildlife habitat, industrial and agricultural supply, commercial and recreational fishing, and other recreational activities.

Watershed Description

The project area is bounded http://ecoviz.csumb.edu/wiki/skins/common/images/button_hr.pngby the Gabilan Range to the east, the Sierra de Salinas range to the west, and the Monterey Bay to the northwest.
TMDL Project Area
The TMDL study is defined by the lower 400 square miles of the Lower Salinas Valley and includes two major watersheds, the Reclamation Canal and Lower Salinas River.

Surface water sources include precipitation, releases from reservoirs, groundwater, and return flows from agricultural irrigation. Mean annual precipitation in the project area ranges from approximately 13 to 16 inches per year with the majority of precipitation occurring between November and April.

One sentence about land use. One sentence about low-flow conditions.

Problem Statement

The Lower Salinas River and eleven of its tributary water bodies are listed as impaired under section 303(d) of the Clean Water Act due to elevated levels of fecal coliform. Observed levels of fecal coliform for some or all these water bodies do not meet the safety criteria for the following designated beneficial uses:

  • Water contact recreation.
  • Non-contact water recreation.
  • Shellfish harvesting for human consumption (under review).


Data Analysis

Fecal indicator bacteria (FIB) are monitored instead of pathogens because direct measurements of pathogens are thought to be too slow, difficult and expensive. There is scientific uncertainty about the effectiveness of FIB as an indicator of pathogen risk. Limitations of FIB include: 1) their presence only indicates the potential presence of human pathogens; 2) the survival levels in the environment may vary between FIB and the pathogens for which they are the indicators; and 3) the FIB are not human-specific so they do not fully assess the human health risk from human enteric viruses and other human specific pathogens. Other limitations include elevated FIB concentrations from nonpoint or other environmental sources.

Escherichia coli (E. coli) composes a large percentage of coliforms in sewage. The potential presence of fecal coliform and specifically, E. coli, can be determined through water sample analysis. Most E. coli strains are harmless and reside naturally in the intestines of humans and animals, but the O157:H7S strain is a human pathogen. The identification of E. coli O157:H7 strain indicates the magnitude of the pathogen problem while more generally indicating the presence of fecal coliforms.

Methods for quantifying bacteria lack the precision found in other methods of water quality analysis. For instance, the Multiple Tube Fermentation (MTF) method estimates of the most probable number (MPN) of bacteria, but this number can vary heavily as an MTF result of 1,600 MPN/100ml has a 95% confidence interval that ranges from 600 to 5,300 MPN/100ml. The Colilert method also results in an MPN of total coliform as well as E. coli, has a slightly better confidence interval in some cases and requires less time than the MTF method. Other methods to more precisely isolate and identify bacterium E. coli O157:H7 such as immunochemical and genetic methods, are more time consuming and costly. Despite these limitations, testing for the presence fecal coliform, including E. coli, remains one of the best available methods for indication of potential fecal contamination and there pathogens. Thus for this project, Methods that were used to identify E. coli O157:H7 included Polymerase chain reaction (PCR), culture, and Pathatrix. Multiple Tube Fermentation (MTF) and Colilert methods were used to provide indications of the presence and magnitude of pathogens.

(Do we need all of the detail in the paragraph above?)

Data sources for the TMDL came from:

  • TMDL Project data set
    • From TMDL Project and USDA
  • Central Coast Ambient Monitoring Program (CCAMP)
  • Entities regulated by the Central Coast Water Board (City of Salinas Stormwater Program)
  • Central Coast Watershed Studies (CCoWS) Team (affiliated with the Watershed Institute at California State University-Monterey Bay)
  • Snap Shot Day monitoring program (Monterey Bay National Marine Sanctuary Citizen Watershed Monitoring Network)

One sentence describing the notes from table 3.1, 3.2 One sentence about rain data and seasonal fluctuations One sentence about the presence of 0157:H7

Source Analysis

A number of sources of fecal coliform in the Lower Salinas Watershed were identified in the TMDL report. These included:

  • Point Sources - a single identifiable localized source of pollution (i.e. you know exactly where the pollution is coming from and can quantify it).
    • Storm drain discharges to storm sewer systems
    • Spills and leaks from sanitary sewer collection and treatment systems
    • concentrated animal feeding operations and dairies (none identified within project area)
  • Nonpoint Sources- pollution derived from many different diffuse sources (i.e. regulation of one point or source will not rectify the problem).
    • Domestic animal discharges in areas that do not drain to a storm water sewer system
    • Onsite waste disposal systems
    • Illegal Dumping
    • Homeless Encampments
    • Sediment Sources
    • Runoff from Irrigated Agriculture
    • Non-controllable natural sources (wind-borne debris)

One or two sentence about delivery potentials. Maybe a sentence or two from the summary of sources section.

Numeric Target

Water quality objectives for FIB are designated based on beneficial uses of the water body.

  • For water contact recreation, the total coliform concentration for a minimum of five samples in any 30 day period should not exceed a log mean of 200 per 100 ml, or 400 per 100 ml for 10% of total samples in any 30 day period.
  • For non-contact water recreation, the total coliform concentration for a minimum of five samples in any 30 day period should not exceed a log mean of 2000 per 100 ml, or 4000 per 100 ml for 10% of total samples in any 30 day period.
  • For shellfish harvesting, the median total coliform concentration in a water column for any 30-day period should not exceed 70 per 100 ml, or 230 per 100 ml for 10% of the total samples in any 30-day period for a five-tube decimal dilution test, or 330 per 100 ml for a three-tube decimal dilution test. The shellfish harvesting beneficial use is being reassessed and water quality standards for shellfish harvesting may be addressed in a separate TMDL listing.

(The water quality objective they used for this study was for water contact recreation. We might want to mention the other two, but maybe not...)

When the total coliform concentration exceeds these levels a water body is considered impaired. However, in order to place it on the impaired list, each site must exceed these minimum contaminant levels a designated number of times depending on sample size. For example, for a sample size of 55-60, 10 exceedances are needed to assert impairment; while a sample size of 116-121, would require 20 exceedances to assert water body impairment.

The EPA is responsible for designating the TMDL criteria and updates it regularly as new research is published regarding human health concerns associated with coliform bacteria contamination. The following example lists recommendations for human health safety in recreational waters.

USEPA recommended criteria for E. coli.

Indicator: E. coli

Risk Level: 8

Single Sample Maximum Allowable Density (per 100 mL)

Geometric Mean Density (per 100 mL): 126

Designated Beach Area (75th percentile): 235

Moderate Full Body Contact Recreation (82nd percentile): 298

Lightly Used Full Body Contact Recreation (90th percentile): 409

Infrequently Used Full Body Contact Recreation (95th percentile): 575

Linkage Analysis

The Linkage Analysis is intended to link the numeric target concentration (amount per volume) to a daily load (amount per day) for the watershed. In the case of fecal coliform, the RWQCB expresses the intent to implement the TMDL based on the target concentration rather than load allocation.

TMDL Development

The TMDL for fecal coliform is based on a three tiered flow regime, wherein each water body has different allowable loads established for high (top 5%), moderate (middle 25%), and low (bottom 60%) flows. Allowable loads are calculated by multiplying the average flow within each flow regime (low, moderate, or high) by the target concentration [volume/time * mass/volume = mass/time]. These target loads were compared to existing loads derived from field data to determine where exceedences are greatest or most frequent.

One sentence about ungaged streams and confluence water bodies. One sentence describing one example from table 7-7.

Margin of Safety

TMDLs are required to include a margin of safety that accounts for uncertainty in the linkage between loading capacity of the watershed and pollutant concentration in the receiving water. In the case of fecal coliform, the goal is for all controllable water sources to meet the target concentration. As this is not a load-based approach, no margin of safety is given.

Critical Conditions and seasonal variation

This TMDL does not identify any "critical" environmental factors, in which a slight change could lead to exceedence of water quality objectives. However, it is noted that pollutant concentration is dependant on flow volume, which is often irregular in our climate. Also, localized areas of stagnant water with fine sediments are favorable for bacteria propagation, and may increase concentrations of Fecal Indicator Bacteria.

TMDL Allocations

Allocations are given as target concentrations. For non-human fecal indicator bacteria, all allocations are the same as the target concentration stated above. The allocation for human FIB is zero. Load-based allocations, based on the method described in the 'TMDL development' section above, are also given in Table 7-7 of the TMDL report.

Public Participation

There are many stakeholders in the Lower Salinas Watershed who would be affected by the implementation of the fecal coliform TMDL. These would include:

  • Agricultural
  • Industry
  • Sewer discharge facilities
  • Wildlife
  • Fisheries
  • Sporting recreational activities
  • Municipal and domestic water supply
  • Homeless Persons

CCRWQCB made stakeholder outreach efforts throughout the development of the TMDL. Data collection and analysis were organized in collaboration with county, state and federal agencies. Public presentations were conducted to inform and elicit stakeholder opinion from a variety of public and private institutions. All the results were made public.

Stakeholders had the opportunity to participate in public meetings where they asked questions and voiced their concerns. One of the concerns described was that some stakeholders claimed specific water bodies in the project area cannot achieve the minimum contaminant levels required for coliform bacteria. The stakeholders added that these water bodies are on private land that have other uses besides recreational. Water flow on these lands is not always natural, especially during summer months when irrigation and groundwater pumping is used widely. Increased concentrations of the fecal indicator bacteria in these water bodies may result from evaporation, and so the minimum required numeric water quality objectives may be exceeded. Furthermore, the steep embankments and muddy substrate surrounding these water bodies makes them inappropriate for recreational use. The CCRWQCB is responsible for addressing these concerns and comments, and for providing official responses before the TMDL listing is approved.

Implementation and Monitoring

The goal of implementation and monitoring is to reduce pathogen loads and achieve the stated TMDLs for the Salinas River Watershed. Potential pathogen sources include: municipal storm drain discharges, domestic animal/livestock discharges, illegal dumping, discharges from homeless persons/encampments, sanitary sewer collection system spills and leaks, wildlife, and sediment bedload resuspension. The implementation of TMDL is complex because of the various sources of pathogenic pollutants. The report lays out an implementation and monitoring road map to identify key pollutants, record progress and obtain results.

Implementation

  • Implementation Actions
  • Evaluation of Implementation Progress
  • Timeline and Milestones
  • Economic Considerations

Monitoring

  • Monitoring Sites
    • Frequency
    • Responsible Parties

A few sentences about the bullet points above.

Monitoring Plan

The Central Coast Water Board will require fecal coliform monitoring in receiving waters to be performed by responsible parties. Fourteen reviewing water monitoring locations have been identified that will allow the Central Coast Water Board to evaluate attainment of the TMDL and allocations. Fecal coliform monitoring for urban stormwater outfall discharges is also proposed as storm drain sampling will assess the effectiveness of management measures but will not be used to determine if the TMDL is attained. Receiving water samples will be used to determine compliance.

Most waterbodies have more than one responsible party indicated for monitoring sites as multiple parties are probable or potential sources of controllable pathogen loads and share responsibility for monitoring. Responsible parties could collaborate in monitoring at these locations

Laws and Policies

The law which creates the TMDL process is the Clean Water Act(CWA). The CWA defines a TMDL as "a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards, and an allocation of that amount to the pollutant's sources."

Future research

While fecal coliforms are useful indicators of pathogenic biological organisms they do not prove their presence/absence. As a result, future research needs to be focused on developing quick, cheap and efficient tests for a wide range of pathogenic organisms. This could be accomplished with the use of DNA chip technology, and or microarrays.

  • Possibly covered in the data analysis section.

References

  1. RWQCB, 2009, ...need full citation here...Total Maximum Daily Load for Fecal Coliform for the Lower Salinas River Watershed, Monterey County, California

Links

Disclaimer

This page may contain student work completed as part of assigned coursework. It may not be accurate. It does not necessary reflect the opinion or policy of CSUMB, its staff, or students.