# Draft 2008 California 303(d)/305(b) Integrated Report

# Supporting Information

## Regional Board 3 - Central Coast Region

Water Body Name: | Gallighan Slough
Water Body ID: | CAR3051003020080616145053
Water Body Type: | River & Stream

DECISION ID | 14121
Pollutant: | Total Coliform
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under sections 2.1 and 3.3 of the Listing Policy. However, on July 19, 2007 USEPA amended the water quality standards for Watsonville Slough and its tributaries (specifically including Gallighan Slough) by removing Shellfish Harvesting as a designated use. Concurrent with the submitted Pathogen TMDL, staff submitted a Use Attainability Analysis (UAA) to amend the beneficial use designations. The USEPA approved the UAA on March 28, 2007.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the beneficial use was removed.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14121

LOE ID: | 13829
Pollutant: | Total Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Shellfish Harvesting
Number of Samples: | 9
Number of Exceedances: | 8
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 8 of 9 samples exceed the criterion for Coliform, Total.
Data Reference: | Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin Shellfish Harvesting objective (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries (page III-12)) states the following: At all areas where shellfish may be harvested for human consumption, the median total coliform concentration throughout the water column for any 30-day period shall not exceed 70 MPN/100mL, not shall more than ten percent of the samples collected during any 30-day period exceed 230 MPN/100mL for a five tube decimal dilution test.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd]
Temporal Representation: | Data was collected over the time period 2/18/2003-11/18/2003.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):

DECISION ID | 14306
Pollutant: | Turbidity
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under sections 2.1 and 3.2 of the Listing Policy. One line of evidence is available in the administrative record to assess this pollutant. Based on section 3.2 the site exceeded numeric objectives for conventional pollutants. According to the binomial distribution, waters shall be placed on the section 303(d) list if the number of measured exceedances supports rejection of the null hypothesis as presented in Table 3.2. Nine of 12 samples exceed the Evaluation Guideline (Sigler et al., 1984) applied to protect for aquatic life beneficial uses. This supports rejection of the null hypothesis. However, at this time staff are unaware of any documentation of steelhead populations in Gallighan Slough. Therefore this Evaluation Guideline is not relevant for this waterbody. Based on the readily available data and information, there is sufficient justification aginst placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. At this time staff are unaware of any documentation of steelhead populations in Gallighan Slough. Therefore this Evaluation Guideline is not relevant for this waterbody. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because this Evaluation Guideline is not relevant for this waterbody.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14306

LOE ID: | 13733
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 12
Number of Exceedances: | 9
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 9 of 12 samples exceed the criterion for Turbidity(NTU).
Data Reference: | Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data
Water Quality Objective/Criterion: | Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Sigler et al. (1984) states that turbidities of 25 NTU's or greater caused reduction in juvenile salmonid growth due to interference with their ability to find food.
Guideline Reference: | Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150
Spatial Representation: | Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd]
Temporal Representation: | Data was collected over the time period 2/18/2003-7/1/2003.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):

DECISION ID | 14307
Pollutant: | pH
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. None of the 8 samples exceed the water quality objective for Water Contact Recreation, Non-Contact Recreation, and Warm Freshwater Habitat. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. However, there are an insufficient number of samples to make a "use rating" decision. Central Coast Water Board staff require a minimum of 26 samples to make a "use rating" decision of Fully Supporting. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of the 8 samples exceed the water quality objective for Water Contact Recreation, Non-Contact Recreation, and Warm Freshwater Habitat and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14307

LOE ID: | 13645
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for water contact recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd]
Temporal Representation: | Data was collected over the time period 2/18/2003-7/1/2003.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):
LOE ID: | 13646
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd]
Temporal Representation: | Data was collected over the time period 2/18/2003-7/1/2003.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):
LOE ID: | 13660
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd]
Temporal Representation: | Data was collected over the time period 2/18/2003-7/1/2003.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):

DECISION ID | 15877
Pollutant: | Pathogens
Final Listing Decision: | List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Source Unknown
TMDL Name: | Watsonville Slough Pathogen
TMDL Project Code: | 35
Date TMDL Approved by USEPA: | 07/19/2007
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | A TMDL has been approved by USEPA (July 19, 2007) for pathogens in Watsonville Slough and four of its tributaries (specifically Gallighan Slough). Gallighan Slough was not specifically identified on the 2006 Section 303(d) list for this pollutant but was included in the TMDL because it is impaired and the source controls are overlapping. This pollutant is being considered for removal from the section 303(d) list under section 4.3 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Four of the 9 samples, tested for E. coli) and 3 of the 9 samples, tested for Fecal Coliform, exceed the water quality objective for Water Contact Recreation. A minimum o f 26 samples are required to determine if water quality standards are being met. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Four of the 9 samples, tested for E. coli) and 3 of the 9 samples, tested for Fecal Coliform, exceed the water quality objective for Water Contact Recreation and these exceed the allowable frequency calculated from the equation in Table 4.2 of the Listing Policy. However, the sample size is insufficient to determine with the power and confidence of the Listing Policy if water quality standards are met or exceeded. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list (being addressed by TMDL category) because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 15877

LOE ID: | 13676
Pollutant: | Escherichia coli (E. Coli)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 9
Number of Exceedances: | 4
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 4 of 9 samples exceed the criterion for Escherichia coli.
Data Reference: | Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data
Water Quality Objective/Criterion: | USEPA Ambient Water Quality Criteria for Bacteria -1986.
Objective/Criterion Reference: | Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
Evaluation Guideline: | Single sample maximum allowable density for E. coli in freshwater is 235 MPN/100mL (as stated in Table 4, page 15)
Guideline Reference: | Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
Spatial Representation: | Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd]
Temporal Representation: | Data was collected over the time period 2/18/2003-11/18/2003.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):
LOE ID: | 13677
Pollutant: | Escherichia coli (E. Coli)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 9
Number of Exceedances: | 0
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Escherichia coli.
Data Reference: | Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 2000/100 ml, nor shall more than ten percent of samples collected during any 30-day period exceed 4000/100 ml. E. coli is a fecal coliform.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd]
Temporal Representation: | Data was collected over the time period 2/18/2003-11/18/2003.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):
LOE ID: | 13795
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 9
Number of Exceedances: | 3
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 3 of 9 samples exceed the criterion for Coliform, Fecal.
Data Reference: | Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for water contact recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 200 MPN/100 ml, nor shall more than ten percent of total samples during any 30-day period exceed 400 MPN/100 ml.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd]
Temporal Representation: | Data was collected over the time period 2/18/2003-11/18/2003.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):
LOE ID: | 13796
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 9
Number of Exceedances: | 1
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 1 of 9 samples exceed the criterion for Coliform, Fecal.
Data Reference: | Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 2000/100 ml, nor shall more than ten percent of samples collected during any 30-day period exceed 4000/100 ml.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd]
Temporal Representation: | Data was collected over the time period 2/18/2003-11/18/2003.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):