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

# Supporting Information

## Regional Board 3 - Central Coast Region

Water Body Name: | San Benito River
Water Body ID: | CAR3053002019981207091641
Water Body Type: | River & Stream

DECISION ID | 4597
Pollutant: | Fecal Coliform
Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list)(2006)
Revision Status | Revised
Sources: | Agriculture | Natural Sources | Other Urban Runoff | Source Unknown
Expected TMDL Completion Date: | 2011
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for removal from the section 303(d) list under section 4.3 of the Listing Policy. Under section 4.3 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. LOE # 1858 summarizes CCAMP data collected monthly in 1998. This same data is also summarized (with additional data) in LOE # 10289. Therefore LOE # 1858 is duplicative of # 10289 and is not counted in the following sample count summary. Twenty-two of 42 samples exceed the Water Contact Recreation water quality objective. The Pajaro River Fecal Coliform TMDL (including Pajaro River, San Benito River, Llagas Creek and Tequisquita Slough) was approved by the Central Coast Regional Board on March 20, 2009 and is currently awaiting to be heard by the State Board. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of not removing 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. Twenty-two of 42 samples exceed the Water Contact Recreation water quality objective and this exceeds the allowable frequency listed in table 3.2 of the Listing Policy. 4. Pursuant to section 4.11 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 removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because it cannot be determined whether applicable water quality standards are being met or exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4597

LOE ID: | 10290
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 42
Number of Exceedances: | 6
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 6 of 42 samples exceed the criterion for Coliform, Fecal.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 1858
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 12
Number of Exceedances: | 5
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Five of 12 samples exceeded the water quality objective (CCAMP, 2004).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Basin Plan: Fecal coliform concentration, based on minimum of not less than five samples or any 30-day period, shall not exceed a log mean of 200/100 ml, nor shall more than ten percent of the total samples during any 30-day period exceed 400/100 ml.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations.
Temporal Representation: | Monthly sampling events. Samples taken from 12/1997 to 12/1998; 12 sampling dates).
Environmental Conditions: |
QAPP Information: | Central Coast Ambient Monitoring Program (CCAMP) QA/QC.
QAPP Information Reference(s):
LOE ID: | 10289
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 42
Number of Exceedances: | 22
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 22 of 42 samples exceed the criterion for Coliform, Fecal.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13406
Pollutant: | Ammonia (Unionized)
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 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the 42 samples exceed the General water quality objective as it applies to the Cold Freshwater Habitat beneficial use. 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. 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 42 samples exceed the General water quality objective as it applies to the Cold Freshwater Habitat beneficial use and this does not exceed the allowable frequency listed in Table 3.1 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 13406

LOE ID: | 9261
Pollutant: | Ammonia (Unionized)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 42
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 0 of 42 samples exceed the criterion for Ammonia as N, Unionized.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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 that the discharge of wastes shall not cause concentrations of unionized ammonia (NH3) to exceed 0.025 mg/l (as N) in receiving waters (page III-4) .
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13409
Pollutant: | Chlorophyll-a
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. One line of evidence is available in the administrative record to assess this pollutant. None of the 40 samples exceed the Evaluation Guideline (North Carolina Administrative code, Title 15A) and the General Water Quality Objective set to protect aquatic life beneficial uses. 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. 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 40 samples exceed the Evaluation Guideline (North Carolina Administrative code, Title 15A) and the General Water Quality Objective set to protect aquatic life beneficial uses 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 13409

LOE ID: | 9265
Pollutant: | Chlorophyll-a
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 40
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 0 of 40 samples exceed the criterion for Chlorophyll a.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect beneficial uses (general objective for biostimulatory substances, Water Quality Control Plan, Central Coast Basin, Chapter III, Section II).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
| North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards
| Water quality standards table
Evaluation Guideline: | North Carolina Administrative code (NCAC), Title 15A - Environmental and Natural Resources, Subchapter 2B-Surface water and wetland standards, Rule 0211-Fresh surface water quality standards for class C waters (Class C is defined as freshwaters protected for secondary recreation, fishing, aquatic life including propagation and survival, and wildlife). Section 3(a) of Rule 0211 applies to all fresh surface waters and states that chlorophyll a is not to exceed 40 ug/L.
Guideline Reference: | North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards
| North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 2/19/1998-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13410
Pollutant: | Chlorpyrifos
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 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the 3 samples exceed the Evaluation Guideline (Sipmann and Finlayson, 2000) applied to protect for aquatic life beneficial uses. 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 16 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 3 samples exceed the Evaluation Guideline (Sipmann and Finlayson, 2000) applied to protect for aquatic life beneficial uses and this does not exceed the allowable frequency listed in Table 3.1 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 13410

LOE ID: | 16347
Pollutant: | Chlorpyrifos
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for San Benito River to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Chlorpyrifos.
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (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 criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
| Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | One hour average maximum concentration 0.025 ug/L as stated in Sipmann and Finlayson (2000).
Guideline Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 1/10/2006-5/17/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 16280
Pollutant: | Chlorpyrifos
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for San Benito River to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Chlorpyrifos.
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (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 criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
| Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | One hour average maximum concentration 0.025 ug/L as stated in Sipmann and Finlayson (2000).
Guideline Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected on a single day 5/3/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13411
Pollutant: | Diazinon
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 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the 3 samples exceed the Evaluation Guideline (Sipmann and Finlayson, 2000) applied to protect for aquatic life beneficial uses. 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 16 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 3 samples exceed the Evaluation Guideline (Sipmann and Finlayson, 2000) applied to protect for aquatic life beneficial uses and this does not exceed the allowable frequency listed in Table 3.1 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 13411

LOE ID: | 16703
Pollutant: | Diazinon
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for San Benito River to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Diazinon.
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (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 criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
| Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | One hour average maximum concentration 0.16 ug/L as stated in Sipmann and Finlayson (2000).
Guideline Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected on a single day 5/3/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 16770
Pollutant: | Diazinon
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for San Benito River to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Diazinon.
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (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 criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
| Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | One hour average maximum concentration 0.16 ug/L as stated in Sipmann and Finlayson (2000).
Guideline Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 1/10/2006-5/17/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13412
Pollutant: | Low Dissolved Oxygen
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. Five lines of evidence are available in the administrative record to assess these pollutants. Two water quality objectives are assessed: Forty-one of the 329 samples exceed the dissolved oxygen water quality objective for Cold Freshwater Habitat and 3 of 47 samples exceed the general water quality objective for oxygen saturation (when applied as a single sample maximum). However, the Basin Plan objective states that the median oxygen saturation value shall not fall below 85% and the median value did not exceed this criterion. 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. Two water quality objectives are assessed: Forty-one of the 329 samples exceed the dissolved oxygen water quality objective for Cold Freshwater Habitat and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. In addition, the median value did not exceed the General Objective. 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 13412

LOE ID: | 11886
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for San Benito River to determine beneficial use support and results are as follows: 1 of 2 samples exceed the criterion for Oxygen, Saturation.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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: Median values should not fall below 85% saturation as a result of controllable water quality conditions.
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 San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 8/30/2005-8/31/2005. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 12268
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 45
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 2 of 45 samples exceed the criterion for Oxygen, Saturation.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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: Median values should not fall below 85% saturation as a result of controllable water quality conditions.
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 17858
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 281
Number of Exceedances: | 40
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for San Benito River to determine beneficial use support and results are as follows: 40 of 281 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: | Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A
| Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B
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, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
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 San Benito River was collected at 4 monitoring sites [ SB-YRD - San Benito River at Y Road, SB-PA - San Benito River at Pajaro junction, SB-BWC - San Benito River at below Willow Creek, SB-BHR - San Benito River at below Hernandez Reservoir]
Temporal Representation: | Data was collected over the time period 11/21/2001-2/11/2007.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
LOE ID: | 11885
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for San Benito River to determine beneficial use support and results are as follows: 1 of 2 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
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 San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 8/30/2005-8/31/2005. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 12267
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 46
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 0 of 46 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13417
Pollutant: | Nitrate
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 3.1 of the Listing Policy. Under section 3.1 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. Two of the 465 samples exceed the Municipal & Domestic Supply water quality objective and one of the 465 samples exceed the Agricultural Supply water quality objective. 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. 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. Two of the 465 samples exceed the Municipal & Domestic Supply water quality objective and one of the 465 samples exceed the Agricultural Supply water quality objective and this does not exceed the allowable frequency listed in Table 3.1 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 13417

LOE ID: | 17707
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 423
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for San Benito River to determine beneficial use support and results are as follows: 2 of 423 samples exceed the criterion for Nitrate as N.
Data Reference: | Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A
| Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin Objective for municipal and domestic supply uses of inland surface waters (Section II.A.2) states the following: waters shall not contain concentrations of chemical constituents in excess of the limits specified in California Code of Regulations, Title 22, Article 4, Chapter 15, Section 64435, Tables 2 and 3 as listed in Table 3-2. The maximum contaminant level listed in Table 3-2 (inorganic and fluoride concentrations not to be exceeded in domestic or municipal supply) for nitrate is 10.0 mg/L (NO3 as N).
Objective/Criterion Reference: | Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
| Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 5 monitoring sites [ SB-YRD - San Benito River at Y Road, SB-PA - San Benito River at Pajaro junction, SB-BWC - San Benito River at below Willow Creek, SB-BHR - San Benito River at below Hernandez Reservoir, SB-AHR]
Temporal Representation: | Data was collected over the time period 8/20/2001-3/13/2007.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
LOE ID: | 17693
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 423
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for San Benito River to determine beneficial use support and results are as follows: 1 of 423 samples exceed the criterion for Nitrate as N.
Data Reference: | Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A
| Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when nitrate exceeds 30 mg/L NO3 as N in irrigation supply water.
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 San Benito River was collected at 5 monitoring sites [ SB-YRD - San Benito River at Y Road, SB-PA - San Benito River at Pajaro junction, SB-BWC - San Benito River at below Willow Creek, SB-BHR - San Benito River at below Hernandez Reservoir, SB-AHR]
Temporal Representation: | Data was collected over the time period 8/20/2001-3/13/2007.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
LOE ID: | 9264
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 42
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 0 of 42 samples exceed the criterion for Nitrate as N.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin Objective for municipal and domestic supply uses of inland surface waters (Section II.A.2) states the following: waters shall not contain concentrations of chemical constituents in excess of the limits specified in California Code of Regulations, Title 22, Article 4, Chapter 15, Section 64435, Tables 2 and 3 as listed in Table 3-2. The maximum contaminant level listed in Table 3-2 (inorganic and fluoride concentrations not to be exceeded in domestic or municipal supply) for nitrate is 10.0 mg/L (NO3 as N).
Objective/Criterion Reference: | Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
| Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 9263
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 42
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 0 of 42 samples exceed the criterion for Nitrate as N.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when nitrate exceeds 30 mg/L NO3 as N in irrigation supply water.
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13407
Pollutant: | Nitrogen, ammonia (Total Ammonia)
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 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the 464 samples exceed the Evaluation Guideline (EPA's Lifetime Health advisory level, 2006) applied to protect the Municipal & Domestic Supply beneficial use. 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. 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 464 samples exceed the Evaluation Guideline (EPA's Lifetime Health advisory level, 2006) applied to protect the Municipal & Domestic Supply beneficial use and this does not exceed the allowable frequency listed in Table 3.1 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 13407

LOE ID: | 17814
Pollutant: | Ammonia as Nitrogen
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 422
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for San Benito River to determine beneficial use support and results are as follows: 0 of 422 samples exceed the criterion for Ammonia As N, Total.
Data Reference: | Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A
| Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B
Water Quality Objective/Criterion: | USEPA Health Advisory 2006 Edition of the Drinking Water Standards and Health Advisories (EPA 822-R-06-013, 2006).
Objective/Criterion Reference: | 2006 edition of the drinking water standards and health advisories. EPA 822-R-03-013
Evaluation Guideline: | EPA's Lifetime Health advisory level for total ammonia is 30.0 mg/L as stated on page 8 of the 2006 edition of the drinking water standards and health advisories. This Advisory Level is defined as "the concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for up to ten days of exposure."
Guideline Reference: | 2006 edition of the drinking water standards and health advisories. EPA 822-R-03-013
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 5 monitoring sites [ SB-YRD - San Benito River at Y Road, SB-PA - San Benito River at Pajaro junction, SB-BWC - San Benito River at below Willow Creek, SB-BHR - San Benito River at below Hernandez Reservoir, SB-AHR]
Temporal Representation: | Data was collected over the time period 8/20/2001-3/13/2007.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
LOE ID: | 9260
Pollutant: | Ammonia as Nitrogen
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 42
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 0 of 42 samples exceed the criterion for Ammonia as N, Total.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | USEPA Health Advisory 2006 Edition of the Drinking Water Standards and Health Advisories (EPA 822-R-06-013, 2006).
Objective/Criterion Reference: | 2006 edition of the drinking water standards and health advisories. EPA 822-R-03-013
Evaluation Guideline: | EPA's Lifetime Health advisory level for total ammonia is 30.0 mg/L as stated on page 8 of the 2006 edition of the drinking water standards and health advisories. This Advisory Level is defined as "the concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for up to ten days of exposure."
Guideline Reference: | 2006 edition of the drinking water standards and health advisories. EPA 822-R-03-013
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13418
Pollutant: | Salinity
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. One line of evidence is available in the administrative record to assess this pollutant. None of the 30 samples exceed the Agricultural Supply water quality objective. 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. 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 30 samples exceed the Agricultural Supply water quality objective 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 13418

LOE ID: | 12282
Pollutant: | Salinity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 30
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 0 of 30 samples exceed the criterion for Salinity.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when salinity exceeds 3.0 ppt in irrigation supply water.
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 1/24/2005-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13416
Pollutant: | Sediment Toxicity
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 3.6 of the Listing Policy. Under section 3.6 a single line of evidence is necessary to assess listing status for toxicity. One line of evidence is available in the administrative record to assess this pollutant in sediment samples. The single sample was not toxic to invertebrate test organisms (did not exhibit a significant increase in mortality compared to the laboratory control) and therefore do not exceed the narrative General Objective for toxicity, set to protect for aquatic life beneficial uses. 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 16 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. The single sample was not toxic to invertebrate test organisms (did not exhibit a significant increase in mortality compared to the laboratory control) and therefore do not exceed the narrative General Objective for toxicity, set to protect for aquatic life beneficial uses. Therefore, this does not exceed the allowable frequency listed in Table 3.1 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 it cannot be determined if applicable water quality standards are not being exceeded because the sample size is insufficient.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 13416

LOE ID: | 24384
Pollutant: | Invertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Sediment
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for San Benito River to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Toxicity, Hyalella azteca Survival (%) 10 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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: | Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected on a single day 5/3/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13419
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. Two lines of evidence are available in the administrative record to assess this pollutant. However, a recent publication (Steelhead/Rainbow Trout (Oncorhynchus mykiss) Resources South of the Golden Gate, California (Becker, G.S and I.J Reining, October 2008) categorizes San Benito River as having "Possibly Absent" steelhead populations and specifically states the following: Staff from NMFS found O. mykiss to be absent from the San Benito River in 2003. Therefore this Turbidity Evaluation Guideline is not relevant to this waterbody. 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. 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. The Turbidity Evaluation Guideline is not relevant to 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 the Turbidity Evaluation Guideline is not relevant to this waterbody.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 13419

LOE ID: | 12283
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 29
Number of Exceedances: | 11
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 11 of 29 samples exceed the criterion for Turbidity(NTU).
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 17522
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 71
Number of Exceedances: | 42
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for San Benito River to determine beneficial use support and results are as follows: 42 of 71 samples exceed the criterion for Turbidity(NTU).
Data Reference: | Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A
| Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B
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 San Benito River was collected at 4 monitoring sites [ SB-YRD - San Benito River at Y Road, SB-PA - San Benito River at Pajaro junction, SB-BWC - San Benito River at below Willow Creek, SB-BHR - San Benito River at below Hernandez Reservoir]
Temporal Representation: | Data was collected over the time period 9/28/2005-2/22/2007.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):

DECISION ID | 13408
Pollutant: | Boron
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture | Grazing-Related Sources | Natural Sources | Other Urban Runoff | Resource Extraction | Source Unknown
Expected TMDL Completion Date: | 2021
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. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of 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. Twenty-four of 30 samples exceeded the water quality objective for Agricultural Supply and this exceeds 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 be placed on the section 303(d) list 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 13408

LOE ID: | 9262
Pollutant: | Boron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Agricultural Supply
Number of Samples: | 30
Number of Exceedances: | 24
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 24 of 30 samples exceed the criterion for Boron, dissolved.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. In addition, waters used for irrigation and livestock watering shall not exceed concentrations for those chemicals listed in Table 3.4 (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). Table 3-4 (page III-9) lists the maximum concentration for boron for irrigation supply is 0.75 mg/L.
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 1/24/2005-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13413
Pollutant: | Electrical Conductivity
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture | Grazing-Related Sources | Natural Sources | Other Urban Runoff | Resource Extraction | Source Unknown
Expected TMDL Completion Date: | 2021
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. Three lines of evidence are 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. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of 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. Sixty-four of 277 samples exceeded the water quality objective for Agricultural Supply and this exceeds 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 be placed on the section 303(d) list 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 13413

LOE ID: | 10291
Pollutant: | Electrical Conductivity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 42
Number of Exceedances: | 5
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 5 of 42 samples exceed the criterion for Conductivity(Us).
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when conductivity exceeds 3.0 mS/cm in irrigation supply water.
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11161
Pollutant: | Electrical Conductivity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 2
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for San Benito River to determine beneficial use support and results are as follows: 1 of 2 samples exceed the criterion for Conductivity(Us).
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when conductivity exceeds 3.0 mS/cm in irrigation supply water.
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 San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 8/30/2005-8/31/2005. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 17510
Pollutant: | Electrical Conductivity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 233
Number of Exceedances: | 58
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for San Benito River to determine beneficial use support and results are as follows: 58 of 233 samples exceed the criterion for Conductivity(Us).
Data Reference: | Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A
| Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when conductivity exceeds 3.0 mS/cm in irrigation supply water.
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 San Benito River was collected at 1 monitoring site [ SB-YRD - San Benito River at Y Road]
Temporal Representation: | Data was collected over the time period 8/20/2001-10/30/2004.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):

DECISION ID | 13414
Pollutant: | Escherichia coli (E. Coli)
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture | Grazing-Related Sources | Natural Sources | Other Urban Runoff
Expected TMDL Completion Date: | 2011
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. Two lines of evidence are available in the administrative record to assess this pollutant. Based on section 3.3 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. The Pajaro River Fecal Coliform TMDL (including Pajaro River, San Benito River, Llagas Creek and Tequisquita Slough) was approved by the Central Coast Regional Board on March 20, 2009 and is currently awaiting to be heard by the State Board. Because E. coli is a fecal coliform staff assume that E. coli will be also be addresses under this TMDL. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of 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. Sixteen of 30 samples exceeded the Evaluation Guideline (USEPA Ambient Water Quality Criteria for Bacteria -1986) applied to protect for Water Contact Recreation and this exceeds 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 be placed on the section 303(d) list 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 13414

LOE ID: | 10308
Pollutant: | Escherichia coli (E. Coli)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 30
Number of Exceedances: | 2
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 2 of 30 samples exceed the criterion for Escherichia coli.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 1/24/2005-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 10292
Pollutant: | Escherichia coli (E. Coli)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 30
Number of Exceedances: | 16
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 16 of 30 samples exceed the criterion for Escherichia coli.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 1/24/2005-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13415
Pollutant: | Unknown Toxicity
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture | Grazing-Related Sources | Natural Sources | Other Urban Runoff | Resource Extraction | Source Unknown
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 and section 3.6 of the Listing Policy. Under section 3.1 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 in water samples. Two of the samples were toxic to test organisms (exhibited a significant increase in mortality or decrease in cell density compared to the laboratory control) and therefore do not exceed the narrative General Objective for toxicity, set to protect for aquatic life beneficial uses. The following is a summary of the results from individual toxicity tests. Two of the 2 samples (tested for toxicity to plants) exhibited significant reduction in cell density relative to the control. In addition, None of the 2 samples (tested for toxicity to vertebrate test organisms) exhibited a significant increase in mortality compared to the laboratory control. Lastly, None of the 2 samples, tested for toxicity to invertebrate test organisms exhibited a significant increase in mortality compared to the laboratory control. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for 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. Both of the samples were toxic to algal test organisms and therefore exceed the narrative General Objective for toxicity, set to protect for aquatic life beneficial uses. This also exceeds the allowable frequency listed in Table 3.1 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 be placed on the section 303(d) list because applicable water quality standards are being exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 13415

LOE ID: | 24385
Pollutant: | Invertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for San Benito River to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Toxicity, Hyalella azteca Survival (%) 10 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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: | Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected on a single day 1/10/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 24396
Pollutant: | Vertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for San Benito River to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Toxicity, Pimephales promelas Survival (%) 7 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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: | Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 1/10/2006-5/17/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 24397
Pollutant: | Plant Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 2
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for San Benito River to determine beneficial use support and results are as follows: 2 of 2 samples exceed the criterion for Toxicity, Selenastrum capricornutum Growth (Cell Density) 4 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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: | Significant reduction in cell count of test organism relative to the control (alpha < 0.05) and cell count <80% of control.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 1/10/2006-5/17/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 24253
Pollutant: | Invertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for San Benito River to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Toxicity, Ceriodaphnia dubia Survival (%) 7 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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: | Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected on a single day 5/17/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 13420
Pollutant: | pH
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Natural Sources
Expected TMDL Completion Date: | 2021
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. Fifteen lines of evidence are 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. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of 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. Sixty-seven of the 377 samples exceed the numeric objective for Municipal & Domestic Supply, Non-Contact Recreation and Water Contact Recreation. Each of these exceeds 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 be placed on the section 303(d) list 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 13420

LOE ID: | 10310
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 43
Number of Exceedances: | 17
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 17 of 43 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin, Section II.A.2. Municipal and Domestic Supply Objectives, Section II.A.2.a states the following: The pH value shall neither be depressed below 6.5 or 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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 10311
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 43
Number of Exceedances: | 17
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 17 of 43 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 10312
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 43
Number of Exceedances: | 17
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 17 of 43 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11162
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for San Benito River to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when pH is greater than 8.4 or less than 6.5 in irrigation supply water.
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 San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 8/30/2005-8/31/2005. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11163
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for San Benito River to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin, Section II.A.2. Municipal and Domestic Supply Objectives, Section II.A.2.a states the following: The pH value shall neither be depressed below 6.5 or 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 San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 8/30/2005-8/31/2005. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11178
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for San Benito River to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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 San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 8/30/2005-8/31/2005. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11179
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for San Benito River to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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 San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 8/30/2005-8/31/2005. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11180
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for San Benito River to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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 San Benito River was collected at 1 monitoring site [ 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 8/30/2005-8/31/2005. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 10309
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 43
Number of Exceedances: | 15
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 15 of 43 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when pH is greater than 8.4 or less than 6.5 in irrigation supply water.
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 10328
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 43
Number of Exceedances: | 6
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for San Benito River to determine beneficial use support and results are as follows: 6 of 43 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
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 San Benito River was collected at 2 monitoring sites [ 305BRI-San Benito River at Highway 25, 305SAN-San Benito at Y Road]
Temporal Representation: | Data was collected over the time period 12/18/1997-3/14/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 17592
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 332
Number of Exceedances: | 19
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for San Benito River to determine beneficial use support and results are as follows: 19 of 332 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A
| Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B
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 San Benito River was collected at 4 monitoring sites [ SB-YRD - San Benito River at Y Road, SB-PA - San Benito River at Pajaro junction, SB-BWC - San Benito River at below Willow Creek, SB-BHR - San Benito River at below Hernandez Reservoir]
Temporal Representation: | Data was collected over the time period 10/23/2001-2/11/2007.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
LOE ID: | 17591
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 332
Number of Exceedances: | 50
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for San Benito River to determine beneficial use support and results are as follows: 50 of 332 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A
| Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B
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 San Benito River was collected at 4 monitoring sites [ SB-YRD - San Benito River at Y Road, SB-PA - San Benito River at Pajaro junction, SB-BWC - San Benito River at below Willow Creek, SB-BHR - San Benito River at below Hernandez Reservoir]
Temporal Representation: | Data was collected over the time period 10/23/2001-2/11/2007.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
LOE ID: | 17576
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 332
Number of Exceedances: | 50
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for San Benito River to determine beneficial use support and results are as follows: 50 of 332 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A
| Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B
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 San Benito River was collected at 4 monitoring sites [ SB-YRD - San Benito River at Y Road, SB-PA - San Benito River at Pajaro junction, SB-BWC - San Benito River at below Willow Creek, SB-BHR - San Benito River at below Hernandez Reservoir]
Temporal Representation: | Data was collected over the time period 10/23/2001-2/11/2007.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
LOE ID: | 17574
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 332
Number of Exceedances: | 36
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for San Benito River to determine beneficial use support and results are as follows: 36 of 332 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A
| Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when pH is greater than 8.4 or less than 6.5 in irrigation supply water.
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 San Benito River was collected at 4 monitoring sites [ SB-YRD - San Benito River at Y Road, SB-PA - San Benito River at Pajaro junction, SB-BWC - San Benito River at below Willow Creek, SB-BHR - San Benito River at below Hernandez Reservoir]
Temporal Representation: | Data was collected over the time period 10/23/2001-2/11/2007.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
LOE ID: | 17575
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 332
Number of Exceedances: | 50
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for San Benito River to determine beneficial use support and results are as follows: 50 of 332 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A
| Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin, Section II.A.2. Municipal and Domestic Supply Objectives, Section II.A.2.a states the following: The pH value shall neither be depressed below 6.5 or 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 San Benito River was collected at 4 monitoring sites [ SB-YRD - San Benito River at Y Road, SB-PA - San Benito River at Pajaro junction, SB-BWC - San Benito River at below Willow Creek, SB-BHR - San Benito River at below Hernandez Reservoir]
Temporal Representation: | Data was collected over the time period 10/23/2001-2/11/2007.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):

DECISION ID | 5920
Pollutant: | Sedimentation/Siltation
Final Listing Decision: | List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (being addressed by USEPA approved TMDL)(2006)
Revision Status | Original
Sources: | Source Unknown
TMDL Name: | Pajaro River Siltation/Sedimentation (including San Benito R., Llagas Cr., Rider Gulch Cr.)
TMDL Project Code: | 140
Date TMDL Approved by USEPA: | 05/03/2007
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for listing under section 2.2 of the Listing Policy. Under this section of the Policy, a minimum of one line of evidence is needed to assess listing status. The Pajaro River Siltation/Sedimentation (including San Benito R., Llagas Cr., Rider Gulch Cr.) TMDL and implementation plan was approved for this water segment-pollutant combination by USEPA on 5/03/07. Based on the readily available information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination in the Water Quality Limited Segments Being Addressed portion of the section 303(d) list.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available information for this recommendation, SWRCB staff conclude that the water body pollutant combination should be placed in the Water Quality Limited Segments Being Addressed category of the section 303(d) list because a TMDL has been approved.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 5920

LOE ID: | 1859
Pollutant: | Sedimentation/Siltation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Not Recorded
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: |
Temporal Representation: |
Environmental Conditions: |
QAPP Information: | QA Info Missing
QAPP Information Reference(s):