Final California 2018 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 3 - Central Coast Region

Water Body Name: Merrit Ditch
Water Body ID: CAR3091101020080604152147
Water Body Type: River & Stream
 
DECISION ID
75906
Region 3     
Merrit Ditch
 
Pollutant: Turbidity
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)(2016)
Revision Status Original
Sources: A Source Unknown
Expected TMDL Completion Date: 2018
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Four lines of evidence are available in the administrative record to assess this pollutant. Fifty-eight of the 65 samples exceed the evaluation guideline for Cold Freshwater Habitat (Sigler et al. 1984) and 55 of the 68 samples exceed the Warm Freshwater Habitat evaluation guideline (Shoup, D.E. and Wahl D.H., 2009), both used to interpret the water quality objective for turbidity.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Fifty-eight of the 65 samples exceed the evaluation guideline for Cold Freshwater Habitat (Sigler et al. 1984) and 55 of the 68 samples exceed the Warm Freshwater Habitat evaluation guideline (Shoup, D.E. and Wahl D.H., 2009), both used to interpret the water quality objective for turbidity. These exceeds the allowable frequency listed in Table 4.2 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 met.
 
Regional Board Decision 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.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 75906, Turbidity
Region 3     
Merrit Ditch
 
LOE ID: 48379
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 40
Number of Exceedances: 36
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 36 of 40 samples exceed the criterion for Turbidity(NTU).
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. (Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Turbidities of 25 NTU or greater can cause a reduction in juvenile salmonid growth due to interference with their ability to find food (Sigler et al. 1984).
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 Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-6/30/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 75906, Turbidity
Region 3     
Merrit Ditch
 
LOE ID: 48380
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 40
Number of Exceedances: 33
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 33 of 40 samples exceed the criterion for Turbidity(NTU).
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Turbidities of 40 NTU or greater can cause a reduction in piscivorous fish (largemouth bass) growth due to interference with their ability to find food (Shoup, D.E. and Wahl D.H., 2009).
Guideline Reference: The Effects of Turbidity on Prey Selection by Piscivorous Largemouth Bass
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-6/30/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 75906, Turbidity
Region 3     
Merrit Ditch
 
LOE ID: 14503
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 25
Number of Exceedances: 22
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 22 of 25 samples exceed the criterion for Turbidity(NTU).
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 75906, Turbidity
Region 3     
Merrit Ditch
 
LOE ID: 14502
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold Freshwater Habitat
 
Number of Samples: 25
Number of Exceedances: 22
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 22 of 25 samples exceed the criterion for Turbidity(NTU).
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
 
DECISION ID
82116
Region 3     
Merrit Ditch
 
Pollutant: Ammonia
Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)(2016)
Revision Status Original
Sources: Agriculture | Domestic Animals/Livestock | Natural Sources
TMDL Name: Salinas River Nutrients
TMDL Project Code: 87
Date TMDL Approved by USEPA: 10/13/2015
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: The pollutant name was changed from ¿Unionized Ammonia¿ to ¿Ammonia¿ in the 2014 assessment cycle. This decision replaces the two previously approved decisions, one for each of the pollutants unionized ammonia and total ammonia. This decision contains all of the LOEs from those decisions in addition to new LOEs.

This pollutant is being considered for placement on the CWA 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.

Six lines of evidence are available in the administrative record to assess pollutant. Four LOEs summarize unionized ammonia data in which seven of the 44 samples exceed the water quality objective for unionized ammonia set to protect aquatic life. Two LOEs summarize total ammonia data and zero of the 66 samples exceed the EPA's Lifetime Health advisory level for total ammonia in drinking water.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the CWA section 303(d) List. There is sufficient justification to place it in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.

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. Seven of the 44 samples exceed the water quality objective for unionized ammonia and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy.
4. The Lower Salinas River Watershed nutrient TMDL was approved by USEPA on October 13, 2015.
5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision 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.

There is sufficient justification to place it in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 82116, Ammonia
Region 3     
Merrit Ditch
 
LOE ID: 14464
 
Pollutant: Ammonia as Nitrogen
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 24
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 0 of 24 samples exceed the criterion for Ammonia As N, Total.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 82116, Ammonia
Region 3     
Merrit Ditch
 
LOE ID: 48385
 
Pollutant: Ammonia (Unionized)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 20
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 4 of 20 samples exceed the criterion for Ammonia as N, Unionized.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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 for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82116, Ammonia
Region 3     
Merrit Ditch
 
LOE ID: 14724
 
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: 24
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 3 of 24 samples exceed the criterion for Ammonia as N, Unionized.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 82116, Ammonia
Region 3     
Merrit Ditch
 
LOE ID: 14723
 
Pollutant: Ammonia (Unionized)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold Freshwater Habitat
 
Number of Samples: 24
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 3 of 24 samples exceed the criterion for Ammonia as N, Unionized.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 82116, Ammonia
Region 3     
Merrit Ditch
 
LOE ID: 48374
 
Pollutant: Ammonia (Unionized)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 20
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 4 of 20 samples exceed the criterion for Ammonia as N, Unionized.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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 for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82116, Ammonia
Region 3     
Merrit Ditch
 
LOE ID: 48373
 
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 Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 42 samples exceed the criterion for Ammonia As N, Total.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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. (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
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 Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-6/30/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
DECISION ID
85558
Region 3     
Merrit Ditch
 
Pollutant: Nitrate
Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)(2016)
Revision Status Original
Sources: Agriculture | Domestic Animals/Livestock | Natural Sources
TMDL Name: Salinas River Nutrients
TMDL Project Code: 87
Date TMDL Approved by USEPA: 10/13/2015
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal on the CWA section 303(d) List under sections 2.2 and 4.1 of the Listing Policy. Under section 4.1 of the Policy, a minimum of one line of evidence is needed to assess listing status.

Twenty-six lines of evidence are available in the administrative record to assess this pollutant. Nineteen of the 22 nitrate samples and 44 of the 53 nitrate/nitrite samples exceed the water quality objective for the Municipal and Domestic Supply beneficial use. Twenty-two of the 22 nitrate samples and 38 of the 39 nitrate/nitrite samples exceed the evaluation guideline (Central Coast Region Technical Report, 2010) for Cold and Warm Freshwater Habitat. In addition, the following evidence supports the conclusion that nitrate contributes to or causes a bio-stimulatory effect in this water segment.

1) Dissolved oxygen for this water body ranged from 4.31 mg/L to 19.54 mg/L. This exceeds (falls below) the Cold Freshwater Habitat water quality objective of 7.0 mg/L. In addition, this waterbody at times exceeds the upper dissolved oxygen screening level of 13.0 mg/L (R3 NNE Technical Report, 2010).
2) Floating algal mats ranged up to 100 % cover, often exceeding the screening threshold of 50% (R3 NNE Technical Report, 2010).
3) Using site-specific data from this waterbody, the California Benthic Biomass Predictor Tool, v. 13 (Tetratech, 2007) predicted a benthic algal contribution to oxygen deficit for this water body ranging from 3.21 mg/L. This exceeds the screening threshold for benthic algal contribution to oxygen deficit of 1.25 mg/L (R3 NNE Technical Report, 2010).
4) Using site-specific data from this waterbody and the Revised Qual2K model, the California Benthic Biomass Predictor Tool, v. 13, QUAL2K model (Tetratech, 2007) predicted algae biomass of 76 g/m2 AFDW. This exceeds the Cold Freshwater Habitat screening threshold for algae biomass of 60 grams/m2 but not the warm water screening threshold of 80 grams/m2, respectively (Creager, et al., 2006).
5) Using site-specific data from this waterbody and the Revised Qual2K model, the California Benthic Biomass Predictor Tool, v. 13 (Tetratech, 2007) predicted benthic chlorophyll a concentrations of 190 mg/m2. This exceeds the Cold Freshwater Habitat screening threshold of 150 mg/m2, but not the Warm Freshwater Habitat screening threshold of 200 mg/m2 (Creager, et al., 2006).
6) Water column chlorophyll a concentration ranged up to 30.92 ug /L, at times exceeding the screening threshold of 15 ug/L (R3 NNE Technical Report, 2010).

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the CWA section 303(d) List. In accordance with section 2.2 of the Policy, there is sufficient justification to place it in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.

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. Nineteen of the 22 nitrate samples and 44 of the 53 nitrate/nitrite samples exceed the water quality objective for the Municipal and Domestic Supply beneficial use. Twenty-two of the 22 nitrate samples and 38 of the 39 nitrate/nitrite samples exceed the evaluation guideline (Central Coast Region Technical Report, 2010) for Cold and Warm Freshwater Habitat. These exceed the allowable frequency listed in Table 4.1 of the Listing Policy and there is evidence in support of the conclusion that nitrate contributes to or causes a bio-stimulatory effect in this water segment..
4. The Lower Salinas River Watershed Nutrient TMDL has been approved by USEPA on 10/13/2005.
5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision 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.
 
State Board Review of Regional Board Conclusion and Recommendation: 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. Nineteen of the 22 nitrate samples and 44 of the 53 nitrate/nitrite samples exceed the water quality objective for the Municipal and Domestic Supply beneficial use. Twenty-two of the 22 nitrate samples and 38 of the 39 nitrate/nitrite samples exceed the evaluation guideline (Central Coast Region Technical Report, 2010) for Cold and Warm Freshwater Habitat. These exceed the allowable frequency listed in Table 4.1 of the Listing Policy and there is evidence in support of the conclusion that nitrate contributes to or causes a bio-stimulatory effect in this water segment..
4. The Lower Salinas River Watershed Nutrient TMDL has been approved by USEPA on 10/13/2005.
5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 85558, Nitrate
Region 3     
Merrit Ditch
 
LOE ID: 48408
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 12
Number of Exceedances: 12
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 12 of 12 samples exceed the criterion for Nitrate as N.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Technical Approach to Develop Nutrient Numeric Endpoints for California. U.S. EPA Region IX. State Water Resources Control Board. 68-C-02-108-To-111
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 10/28/2008-12/9/2009.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 85558, Nitrate
Region 3     
Merrit Ditch
 
LOE ID: 28165
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 10
Number of Exceedances: 10
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data for this assessment unit was collected by one monitoring project: CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth)
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
Guideline Reference: Technical Approach to Develop Nutrient Numeric Endpoints for California. U.S. EPA Region IX. State Water Resources Control Board. 68-C-02-108-To-111
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 2/22/2005-12/13/2005. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 85558, Nitrate
Region 3     
Merrit Ditch
 
LOE ID: 28166
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 10
Number of Exceedances: 10
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data for this assessment unit was collected by one monitoring project: CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth)
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
Guideline Reference: Technical Approach to Develop Nutrient Numeric Endpoints for California. U.S. EPA Region IX. State Water Resources Control Board. 68-C-02-108-To-111
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 2/22/2005-12/13/2005. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 85558, Nitrate
Region 3     
Merrit Ditch
 
LOE ID: 48407
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 12
Number of Exceedances: 11
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 11 of 12 samples exceed the criterion for Nitrate as N.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for nitrate (NO3 as N) incorporated by reference in the Basin Plan is 10.0 mg/L (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 10/28/2008-12/9/2009.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 85558, Nitrate
Region 3     
Merrit Ditch
 
LOE ID: 14289
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 10
Number of Exceedances: 8
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 8 of 10 samples exceed the criterion for Nitrate as N.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
Objective/Criterion Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 2/22/2005-12/13/2005. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 85558, Nitrate
Region 3     
Merrit Ditch
 
LOE ID: 48406
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 12
Number of Exceedances: 12
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 12 of 12 samples exceed the criterion for Nitrate as N.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Technical Approach to Develop Nutrient Numeric Endpoints for California. U.S. EPA Region IX. State Water Resources Control Board. 68-C-02-108-To-111
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 10/28/2008-12/9/2009.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 85558, Nitrate
Region 3     
Merrit Ditch
 
LOE ID: 48359
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 39
Number of Exceedances: 38
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 38 of 39 samples exceed the criterion for Nitrate/Nitrite as N.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Technical Approach to Develop Nutrient Numeric Endpoints for California. U.S. EPA Region IX. State Water Resources Control Board. 68-C-02-108-To-111
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 85558, Nitrate
Region 3     
Merrit Ditch
 
LOE ID: 48410
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 39
Number of Exceedances: 34
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 34 of 39 samples exceed the criterion for Nitrate/Nitrite as N.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for nitrate + nitrite (as N) that is incorporated by reference in the Basin Plan is 10.0 mg/L (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 85558, Nitrate
Region 3     
Merrit Ditch
 
LOE ID: 48409
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 39
Number of Exceedances: 38
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 38 of 39 samples exceed the criterion for Nitrate/Nitrite as N.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Technical Approach to Develop Nutrient Numeric Endpoints for California. U.S. EPA Region IX. State Water Resources Control Board. 68-C-02-108-To-111
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 85558, Nitrate
Region 3     
Merrit Ditch
 
LOE ID: 14451
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 14
Number of Exceedances: 10
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 10 of 14 samples exceed the criterion for Nitrate/Nitrite as N.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: OEHHA public Health Goals for Nitrate and Nitrogen in Drinking Water (December 1997). Page 6.
Objective/Criterion Reference: Public health goals for nitrate and nitrite in drinking water
 
Evaluation Guideline: OEHHA Public Health Goal states that sum of the concentration of nitrate + nitrite shall not exceed 10 mg/L (NO3+NO2 expressed as N).
Guideline Reference: Public health goals for nitrate and nitrite in drinking water
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
 
DECISION ID
82117
Region 3     
Merrit Ditch
 
Pollutant: Oxygen, Dissolved
Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)(2016)
Revision Status Original
Sources: Agriculture | Domestic Animals/Livestock | Natural Sources
TMDL Name: Salinas River Nutrients
TMDL Project Code: 87
Date TMDL Approved by USEPA: 10/13/2015
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Eight lines of evidence are available in the administrative record to assess this pollutant. Two water quality objectives are assessed. Twelve of the 61 samples exceeded the water quality objective for dissolved oxygen in Cold Freshwater Habitats and four of the 61 samples also exceeded the water quality objective for dissolved oxygen in Warm Freshwater Habitats. The Basin Plan general water quality objective for oxygen saturation states that the median value shall not fall below 85% saturation. However, the oxygen saturation objective is only applied ¿for waters not mentioned by a specific beneficial use¿¿ and this water body is designated for both Cold and Warm Freshwater Habitats. Therefore, the use support rating for oxygen saturation is set at Insufficient Information.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the CWA section 303(d) List. There is sufficient justification to place it in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.

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. Twelve of the 61 samples exceeded the water quality objective for dissolved oxygen in Cold Freshwater Habitats and this exceeds the allowable frequency listed in Table 4.2 of the Listing Policy.
4. The Lower Salinas River Watershed nutrient TMDL was approved by USEPA on October 13, 2015.
5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision 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.

There is sufficient justification to place it in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 82117, Oxygen, Dissolved
Region 3     
Merrit Ditch
 
LOE ID: 48362
 
Pollutant: Dissolved oxygen saturation
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 36
Number of Exceedances: 8
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 8 of 36 samples exceed the criterion for Oxygen, Saturation.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Median values should not fall below 85% saturation as a result of controllable water quality conditions (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82117, Oxygen, Dissolved
Region 3     
Merrit Ditch
 
LOE ID: 14684
 
Pollutant: Dissolved oxygen saturation
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold Freshwater Habitat
 
Number of Samples: 25
Number of Exceedances: 17
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 17 of 25 samples exceed the criterion for Oxygen, Saturation.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 82117, Oxygen, Dissolved
Region 3     
Merrit Ditch
 
LOE ID: 48361
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 36
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 1 of 36 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82117, Oxygen, Dissolved
Region 3     
Merrit Ditch
 
LOE ID: 14741
 
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: 25
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 3 of 25 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 82117, Oxygen, Dissolved
Region 3     
Merrit Ditch
 
LOE ID: 14740
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold Freshwater Habitat
 
Number of Samples: 25
Number of Exceedances: 8
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 8 of 25 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan, Central Coast Basin, Cold Water Habitat Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 82117, Oxygen, Dissolved
Region 3     
Merrit Ditch
 
LOE ID: 48360
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 36
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 4 of 36 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82117, Oxygen, Dissolved
Region 3     
Merrit Ditch
 
LOE ID: 48363
 
Pollutant: Dissolved oxygen saturation
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 36
Number of Exceedances: 8
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 8 of 36 samples exceed the criterion for Oxygen, Saturation.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Median values should not fall below 85% saturation as a result of controllable water quality conditions (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82117, Oxygen, Dissolved
Region 3     
Merrit Ditch
 
LOE ID: 14754
 
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: 25
Number of Exceedances: 17
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 17 of 25 samples exceed the criterion for Oxygen, Saturation.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
 
DECISION ID
90189
Region 3     
Merrit Ditch
 
Pollutant: Toxicity
Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)(2016)
Revision Status Original
Sources: Agriculture
TMDL Name: Lower Salinas River Chlorpyrifos and Diazinon TMDL
TMDL Project Code: 133
Date TMDL Approved by USEPA: 10/07/2011
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal from the CWA section 303(d) List under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Twelve lines of evidence are available in the administrative record to assess this pollutant. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day and time at the same location.

Four LOEs summarize sediment samples. Two sediment samples are summarized in LOEs using the test organism as the pollutant (i.e. invertebrate toxicity) and three additional sediment samples are summarized in LOEs using the pollutant name ¿toxicity¿. Therefore, five total samples are available to assess toxic effects in sediment samples. Five of the five sediment samples resulted in a significant toxic effect to one or more test organisms and therefore exceeds the water quality objective for aquatic life protection.

Eight LOEs summarize water samples. Seven water samples are summarized in LOEs using each of the test organisms as the pollutant name (i.e. plant toxicity, invertebrate toxicity or vertebrate toxicity) and eleven additional water samples are summarized in LOEs using the pollutant name ¿toxicity¿. Therefore, eighteen total samples are available to assess toxic effects in water samples. Twelve of the eighteen water samples resulted in a significant toxic effect to one or more test organisms and therefore exceeds the water quality objective for aquatic life protection.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the CWA section 303(d) List. There is sufficient justification to place it in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.

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. Five of 5 sediment samples and 12 of the 18 water samples resulted in a significant toxic effect to one or more test organisms and therefore also exceed the water quality objective for aquatic life protection and these exceed the allowable frequency listed in Table 4.1 of the Listing Policy.
4. The Lower Salinas River Watershed Chlorpyrifos and Diazinon TMDL was approved by USEPA on October 7, 2011.
5. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
 
Regional Board Decision 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.

There is sufficient justification to place it in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 90189, Toxicity
Region 3     
Merrit Ditch
 
LOE ID: 23873
 
Pollutant: Invertebrate Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold 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 CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPnorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 2 of 2 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: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 4/12/2005-5/24/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 90189, Toxicity
Region 3     
Merrit Ditch
 
LOE ID: 23874
 
Pollutant: Invertebrate Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
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 CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPnorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 2 of 2 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: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 4/12/2005-5/24/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 90189, Toxicity
Region 3     
Merrit Ditch
 
LOE ID: 24040
 
Pollutant: Invertebrate Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold Freshwater Habitat
 
Number of Samples: 7
Number of Exceedances: 2
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPnorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 1 of 4 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: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 2/16/2005-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 90189, Toxicity
Region 3     
Merrit Ditch
 
LOE ID: 24050
 
Pollutant: Invertebrate Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 7
Number of Exceedances: 2
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPnorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 1 of 4 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: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 2/16/2005-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 90189, Toxicity
Region 3     
Merrit Ditch
 
LOE ID: 24017
 
Pollutant: Plant Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPnorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 0 of 6 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: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 2/16/2005-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 90189, Toxicity
Region 3     
Merrit Ditch
 
LOE ID: 24007
 
Pollutant: Vertebrate Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPnorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 0 of 4 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: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 3/21/2005-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 90189, Toxicity
Region 3     
Merrit Ditch
 
LOE ID: 55140
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 11
Number of Exceedances: 10
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Eleven samples were collected to evaluate water toxicity. Ten of the eleven samples exhibited significant toxicity. The toxicity tests for the samples included survival and reproduction of Ceriodaphnia dubia, survival and growth of Pimephales promelas and total cell count (growth) of Selenastrum capricornutum. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location. Samples exhibited significant toxicity to survival of Ceriodaphnia dubia (8 samples), survival Hyalella azteca (1 sample) and growth Pimephales promelas (1 sample). It should be noted that the samples collected in 2005 and 2006, in the data file associated with this LOE, are not included in this LOE because they were included in the previous assessment cycle.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Significant effect is defined here using a two-tier approach consistent with the method used by the SWAMP program. The effect must be significant when compared to the control sample based on statistical test alpha level of 0.05 (Probability field in data set) AND the mean must be more than 20 percent different from the control (PercentControl field in data set).
Guideline Reference: SWAMP_Memo_Toxicity_Data_Intrepretation
 
Spatial Representation: The samples were collected at 309MER Merritt Ditch.
Temporal Representation: The samples were collected from October 2007 to March 2010.
Environmental Conditions:
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format. QAPP for the Cooperative Monitoring program for Agriculture in Region 3.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 90189, Toxicity
Region 3     
Merrit Ditch
 
LOE ID: 79216
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 11
Number of Exceedances: 10
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Eleven samples were collected to evaluate water toxicity. Ten of the eleven samples exhibited significant toxicity. The toxicity tests for the samples included survival and reproduction of Ceriodaphnia dubia, survival and growth of Pimephales promelas and total cell count (growth) of Selenastrum capricornutum. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location. Samples exhibited significant toxicity to survival of Ceriodaphnia dubia (8 samples), survival Hyalella azteca (1 sample) and growth Pimephales promelas (1 sample). It should be noted that the samples collected in 2005 and 2006, in the data file associated with this LOE, are not included in this LOE because they were included in the previous assessment cycle.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Significant effect is defined here using a two-tier approach consistent with the method used by the SWAMP program. The effect must be significant when compared to the control sample based on statistical test alpha level of 0.05 (Probability field in data set) AND the mean must be more than 20 percent different from the control (PercentControl field in data set).
Guideline Reference: Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. EPA-821-R-02-012
 
Spatial Representation: The samples were collected at 309MER Merritt Ditch.
Temporal Representation: The samples were collected from October 2007 to March 2010.
Environmental Conditions:
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format. QAPP for the Cooperative Monitoring program for Agriculture in Region 3.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 90189, Toxicity
Region 3     
Merrit Ditch
 
LOE ID: 55141
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 3
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Three samples were collected to evaluate sediment toxicity. All three samples exhibited significant toxicity to Hyalella azteca. The toxicity tests included growth and survival of Hyalella azteca. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location. Samples collected in 2006, in the data file associated with this LOE, are not included in this LOE because they were included in the previous assessment cycle.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Significant effect is defined here using a two-tier approach consistent with the method used by the SWAMP program. The effect must be significant when compared to the control sample based on statistical test alpha level of 0.05 (Probability field in data set) AND the mean must be more than 20 percent different from the control (PercentControl field in data set).
Guideline Reference: SWAMP_Memo_Toxicity_Data_Intrepretation
Guideline Reference: Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates, Second Edition. U.S. Environmental Protection Agency Office of Research and Development, Duluth, MI , U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-600/R-99/064
 
Spatial Representation: The samples were collected at 309MER Merritt Ditch.
Temporal Representation: The samples were collected annually in April 2007, 2008 and 2009.
Environmental Conditions:
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format. QAPP for the Cooperative Monitoring program for Agriculture in Region 3.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 90189, Toxicity
Region 3     
Merrit Ditch
 
LOE ID: 79217
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 3
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Three samples were collected to evaluate sediment toxicity. All three samples exhibited significant toxicity to Hyalella azteca. The toxicity tests included growth and survival of Hyalella azteca. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location. Samples collected in 2006, in the data file associated with this LOE, are not included in this LOE because they were included in the previous assessment cycle.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Significant effect is defined here using a two-tier approach consistent with the method used by the SWAMP program. The effect must be significant when compared to the control sample based on statistical test alpha level of 0.05 (Probability field in data set) AND the mean must be more than 20 percent different from the control (PercentControl field in data set).
Guideline Reference: Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. EPA-821-R-02-012
 
Spatial Representation: The samples were collected at 309MER Merritt Ditch.
Temporal Representation: The samples were collected annually in April 2007, 2008 and 2009.
Environmental Conditions:
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format. QAPP for the Cooperative Monitoring program for Agriculture in Region 3.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 90189, Toxicity
Region 3     
Merrit Ditch
 
LOE ID: 24018
 
Pollutant: Plant Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPnorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 0 of 6 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: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 2/16/2005-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 90189, Toxicity
Region 3     
Merrit Ditch
 
LOE ID: 24006
 
Pollutant: Vertebrate Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPnorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 0 of 4 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: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 3/21/2005-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
 
DECISION ID
75325
Region 3     
Merrit Ditch
 
Pollutant: Chlorophyll-a
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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.

Four lines of evidence are available in the administrative record to assess this pollutant. Zero of the 60 samples exceed the evaluation guideline (North Carolina Administrative code, Title 15A) used to interpret the narrative water quality objective for bio-stimulation risk and 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 CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Zero of the 60 samples exceed the evaluation guideline 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.
 
Regional Board Decision 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.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 75325, Chlorophyll-a
Region 3     
Merrit Ditch
 
LOE ID: 48386
 
Pollutant: Chlorophyll-a
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 36
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 36 samples exceed the criterion for Chlorophyll a.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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 for the Central Coastal Basin
 
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
Guideline Reference: Water quality standards table
Guideline Reference: 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 Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 75325, Chlorophyll-a
Region 3     
Merrit Ditch
 
LOE ID: 14738
 
Pollutant: Chlorophyll-a
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold Freshwater Habitat
 
Number of Samples: 24
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 0 of 24 samples exceed the criterion for Chlorophyll a.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
Objective/Criterion Reference: North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards
Objective/Criterion Reference: 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
Guideline Reference: 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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 75325, Chlorophyll-a
Region 3     
Merrit Ditch
 
LOE ID: 14739
 
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: 24
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 0 of 24 samples exceed the criterion for Chlorophyll a.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
Objective/Criterion Reference: North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards
Objective/Criterion Reference: 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
Guideline Reference: 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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 75325, Chlorophyll-a
Region 3     
Merrit Ditch
 
LOE ID: 48387
 
Pollutant: Chlorophyll-a
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 36
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 36 samples exceed the criterion for Chlorophyll a.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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 for the Central Coastal Basin
 
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: Water quality standards table
Guideline Reference: North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards
Guideline Reference: 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 Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
DECISION ID
81573
Region 3     
Merrit Ditch
 
Pollutant: Chlorpyrifos
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Five lines of evidence are available in the administrative record to assess this pollutant. Zero of five water samples exceeded the aquatic life evaluation guideline (Siepmann and Finlayson 2000). Zero of three samples exceeded the USEPA drinking water health advisory. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported using table 3.1.

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. Zero of five water samples exceeded the aquatic life evaluation guideline (Siepmann and Finlayson 2000, with minor corrections to significant figures as described in Beaulaurier et al., 2005) 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.
 
Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 81573, Chlorpyrifos
Region 3     
Merrit Ditch
 
LOE ID: 48388
 
Pollutant: Chlorpyrifos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Chlorpyrifos.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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. (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The freshwater criterion continuous concentration to protect aquatic organisms is 0.015 ug/L (Siepmann and Finlayson 2000, with minor corrections to significant figures as described in Beaulaurier et al., 2005).
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 (with minor corrections to significant figures as described in Beaulaurier et al., 2005).
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 81573, Chlorpyrifos
Region 3     
Merrit Ditch
 
LOE ID: 48395
 
Pollutant: Chlorpyrifos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Chlorpyrifos.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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. (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The freshwater criterion continuous concentration to protect aquatic organisms is 0.015 ug/L (Siepmann and Finlayson 2000, with minor corrections to significant figures as described in Beaulaurier et al., 2005).
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 (with minor corrections to significant figures as described in Beaulaurier et al., 2005).
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 81573, Chlorpyrifos
Region 3     
Merrit Ditch
 
LOE ID: 15128
 
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 CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch 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: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 Control Plan (Basin Plan) - Central Coast Region (Region 3)
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
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 81573, Chlorpyrifos
Region 3     
Merrit Ditch
 
LOE ID: 55149
 
Pollutant: Chlorpyrifos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Chlorpyrifos.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The USEPA drinking water health advisory for chlorpyrifos is 2 µg/L.
Guideline Reference: 2011 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 81573, Chlorpyrifos
Region 3     
Merrit Ditch
 
LOE ID: 15127
 
Pollutant: Chlorpyrifos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold 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 CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch 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: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 Control Plan (Basin Plan) - Central Coast Region (Region 3)
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
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
 
DECISION ID
82174
Region 3     
Merrit Ditch
 
Pollutant: Demeton
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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. Zero of the five samples exceed the evaluation guideline for aquatic life uses (USEPA National Recommended Water Quality Criteria). This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information' unless the beneficial use is not supported.

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 CWA 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. Zero of the five samples exceed the evaluation guideline for aquatic life 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.
 
Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 82174, Demeton
Region 3     
Merrit Ditch
 
LOE ID: 55150
 
Pollutant: Demeton
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial 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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Demeton.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The Demeton criterion continuous concentration for the protection of freshwater aquatic life is 0.1 ug/L (National Recommended Water Quality Criteria, 2009).
Guideline Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82174, Demeton
Region 3     
Merrit Ditch
 
LOE ID: 55151
 
Pollutant: Demeton
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Demeton.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The Demeton criterion continuous concentration for the protection of freshwater aquatic life is 0.1 ug/L (National Recommended Water Quality Criteria, 2009).
Guideline Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82174, Demeton
Region 3     
Merrit Ditch
 
LOE ID: 55153
 
Pollutant: Demeton
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Demeton.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The USEPA National Recomm. WQ criteria, 4-day avg. is 0.1 ug/L.
Guideline Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82174, Demeton
Region 3     
Merrit Ditch
 
LOE ID: 55152
 
Pollutant: Demeton
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Demeton.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The USEPA National Recomm. WQ criteria, 4-day avg. is 0.1 ug/L.
Guideline Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
DECISION ID
82228
Region 3     
Merrit Ditch
 
Pollutant: Dichlorvos
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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.

Six lines of evidence are available in the administrative record to assess this pollutant. Zero of the five samples exceed the evaluation guideline for aquatic life uses (USEPA maximum acceptable toxicant concentration (MATC)) and zero of the five samples exceed the evaluation guideline for drinking water (National health advisory level (USEPA IRIS one-in-a-million cancer risk estimate from oral exposure). This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information' unless the beneficial use is not supported.

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 CWA 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 Zero of the five samples exceed the evaluation guidelines 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.
 
Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 82228, Dichlorvos
Region 3     
Merrit Ditch
 
LOE ID: 55092
 
Pollutant: Dichlorvos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Dichlorvos.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The USEPA IRIS one-in-a-million cancer risk estimate from oral exposure for dichlorvos is 0.1 ug/L.
Guideline Reference: IRIS Database Calculations (summary)
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82228, Dichlorvos
Region 3     
Merrit Ditch
 
LOE ID: 55160
 
Pollutant: Dichlorvos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Dichlorvos.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for ddvp (dichlorvos) is the maximum acceptable toxicant concentration (MATC) of 7.2 ug/L. The MATC (or Chronic Value as defined in USEPA 1985, P20 section F) is calculated as the geometric mean of the lowest observed effect concentration (LOEC) of 10.1 ug/L and the no observed effect concentration (NOEC) of 5.2 ug/L as determined in a 61 day toxicity study with rainbow trout, Oncorhynchus mykiss. Threshold values (LOEC and NOEC) are from USEPA Office of Pesticide Programs Ecotoxicity database.
Guideline Reference: OPP Pesticide Ecotoxicity Database.
Guideline Reference: Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82228, Dichlorvos
Region 3     
Merrit Ditch
 
LOE ID: 55158
 
Pollutant: Dichlorvos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Dichlorvos.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for ddvp (dichlorvos) is the maximum acceptable toxicant concentration (MATC) of 7.2 ug/L. The MATC (or Chronic Value as defined in USEPA 1985, P20 section F) is calculated as the geometric mean of the lowest observed effect concentration (LOEC) of 10.1 ug/L and the no observed effect concentration (NOEC) of 5.2 ug/L as determined in a 61 day toxicity study with rainbow trout, Oncorhynchus mykiss. Threshold values (LOEC and NOEC) are from USEPA Office of Pesticide Programs Ecotoxicity database.
Guideline Reference: OPP Pesticide Ecotoxicity Database.
Guideline Reference: Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82228, Dichlorvos
Region 3     
Merrit Ditch
 
LOE ID: 55159
 
Pollutant: Dichlorvos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial 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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Dichlorvos.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for ddvp (dichlorvos) is the maximum acceptable toxicant concentration (MATC) of 7.2 ug/L. The MATC (or Chronic Value as defined in USEPA 1985, P20 section F) is calculated as the geometric mean of the lowest observed effect concentration (LOEC) of 10.1 ug/L and the no observed effect concentration (NOEC) of 5.2 ug/L as determined in a 61 day toxicity study with rainbow trout, Oncorhynchus mykiss. Threshold values (LOEC and NOEC) are from USEPA Office of Pesticide Programs Ecotoxicity database.
Guideline Reference: OPP Pesticide Ecotoxicity Database.
Guideline Reference: Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82228, Dichlorvos
Region 3     
Merrit Ditch
 
LOE ID: 79218
 
Pollutant: Dichlorvos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Dichlorvos.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The USEPA IRIS one-in-a-million cancer risk estimate from oral exposure for dichlorvos is 0.1 ug/L.
Guideline Reference: OPP Pesticide Ecotoxicity Database.
Guideline Reference: Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82228, Dichlorvos
Region 3     
Merrit Ditch
 
LOE ID: 55157
 
Pollutant: Dichlorvos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Dichlorvos.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for ddvp (dichlorvos) is the maximum acceptable toxicant concentration (MATC) of 7.2 ug/L. The MATC (or Chronic Value as defined in USEPA 1985, P20 section F) is calculated as the geometric mean of the lowest observed effect concentration (LOEC) of 10.1 ug/L and the no observed effect concentration (NOEC) of 5.2 ug/L as determined in a 61 day toxicity study with rainbow trout, Oncorhynchus mykiss. Threshold values (LOEC and NOEC) are from USEPA Office of Pesticide Programs Ecotoxicity database.
Guideline Reference: OPP Pesticide Ecotoxicity Database.
Guideline Reference: Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
DECISION ID
82229
Region 3     
Merrit Ditch
 
Pollutant: Dimethoate
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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.

Six lines of evidence are available in the administrative record to assess this pollutant. Zero of the five samples exceed the evaluation guideline for aquatic life uses (USEPA maximum acceptable toxicant concentration (MATC)) and zero of the five samples exceed the evaluation guideline for drinking water (National health advisory level (California Department of Health Services notification level). This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information' unless the beneficial use is not supported.

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 CWA 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 Zero of the five samples exceed the evaluation guidelines 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.
 
Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 82229, Dimethoate
Region 3     
Merrit Ditch
 
LOE ID: 55095
 
Pollutant: Dimethoate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial 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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Dimethoate.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for Dimethoate is the median lethal concentration (LC50) of 43 ug/L, as determined in a 96 hour toxicity test with the stonefly, Pteronarcys californica (USEPA Office of Pesticide Programs Ecotoxicity database).
Guideline Reference: OPP Pesticide Ecotoxicity Database.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82229, Dimethoate
Region 3     
Merrit Ditch
 
LOE ID: 55097
 
Pollutant: Dimethoate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Dimethoate.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for Dimethoate is the median lethal concentration (LC50; 43 ug/L). This is based on the lowest LC50 value in the Office of Pesticide Programs Ecotoxicity database (stonefly 96 hr test).
Guideline Reference: OPP Pesticide Ecotoxicity Database.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82229, Dimethoate
Region 3     
Merrit Ditch
 
LOE ID: 55094
 
Pollutant: Dimethoate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Dimethoate.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The California Department of Health Services notification level for dimethoate is 1 µg/L.
Guideline Reference: Drinking Water Notification Levels and Response Levels
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82229, Dimethoate
Region 3     
Merrit Ditch
 
LOE ID: 55093
 
Pollutant: Dimethoate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Dimethoate.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The California Department of Health Services notification level for dimethoate is 1 µg/L.
Guideline Reference: Drinking Water Notification and Response Levels: An Overview
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82229, Dimethoate
Region 3     
Merrit Ditch
 
LOE ID: 55096
 
Pollutant: Dimethoate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Dimethoate.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for Dimethoate is the median lethal concentration (LC50) of 43 ug/L, as determined in a 96 hour toxicity test with the stonefly, Pteronarcys californica (USEPA Office of Pesticide Programs Ecotoxicity database).
Guideline Reference: OPP Pesticide Ecotoxicity Database.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82229, Dimethoate
Region 3     
Merrit Ditch
 
LOE ID: 55098
 
Pollutant: Dimethoate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Dimethoate.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for Dimethoate is the median lethal concentration (LC50; 43 ug/L). This is based on the lowest LC50 value in the Office of Pesticide Programs Ecotoxicity database (stonefly 96 hr test).
Guideline Reference: OPP Pesticide Ecotoxicity Database.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
DECISION ID
82335
Region 3     
Merrit Ditch
 
Pollutant: Disulfoton
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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. Zero of the five samples exceed the evaluation guideline for drinking water (USEPA drinking water health advisory level). This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information' unless the beneficial use is not supported.

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 CWA 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 Zero of the five samples exceed the evaluation guideline 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.
 
Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 82335, Disulfoton
Region 3     
Merrit Ditch
 
LOE ID: 55101
 
Pollutant: Disulfoton
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Disulfoton.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The USEPA drinking water health advisory for disulfoton is 0.7 µg/L.
Guideline Reference: 2011 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82335, Disulfoton
Region 3     
Merrit Ditch
 
LOE ID: 55102
 
Pollutant: Disulfoton
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Disulfoton.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The USEPA drinking water health advisory for disulfoton is 0.7 µg/L.
Guideline Reference: 2011 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
DECISION ID
81320
Region 3     
Merrit Ditch
 
Pollutant: Ethoprop
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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. Zero of the five samples exceed the evaluation guideline for aquatic life uses (USEPA maximum acceptable toxicant concentration (MATC)). This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information' unless the beneficial use is not supported.

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 CWA 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 Zero of the five samples exceed the evaluation guideline 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.
 
Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 81320, Ethoprop
Region 3     
Merrit Ditch
 
LOE ID: 55105
 
Pollutant: Ethoprop
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial 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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Ethoprop.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for Ethoprop is the maximum acceptable toxicant concentration (MATC) of 1.4 ug/L. The MATC (or Chronic Value as defined in USEPA 1985, P20 section F) is calculated as the geometric mean of the lowest observed effect concentration (LOEC) of 2.4 ug/L and the no observed effect concentration (NOEC) of 0.80 ug/L, as determined in a 21 day toxicity study with the water flea, Daphnia magna. Threshold values (LOEC and NOEC) are from USEPA Office of Pesticide Programs Ecotoxicity database.
Guideline Reference: OPP Pesticide Ecotoxicity Database.
Guideline Reference: Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 81320, Ethoprop
Region 3     
Merrit Ditch
 
LOE ID: 55103
 
Pollutant: Ethoprop
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Ethoprop.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for Ethoprop is the maximum acceptable toxicant concentration (MATC) of 1.4 ug/L. The MATC (or Chronic Value as defined in USEPA 1985, P20 section F) is calculated as the geometric mean of the lowest observed effect concentration (LOEC) of 2.4 ug/L and the no observed effect concentration (NOEC) of 0.80 ug/L, as determined in a 21 day toxicity study with the water flea, Daphnia magna. Threshold values (LOEC and NOEC) are from USEPA Office of Pesticide Programs Ecotoxicity database.
Guideline Reference: OPP Pesticide Ecotoxicity Database.
Guideline Reference: Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 81320, Ethoprop
Region 3     
Merrit Ditch
 
LOE ID: 55104
 
Pollutant: Ethoprop
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Ethoprop.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for Ethoprop is the maximum acceptable toxicant concentration (MATC) of 1.4 ug/L. The MATC (or Chronic Value as defined in USEPA 1985, P20 section F) is calculated as the geometric mean of the lowest observed effect concentration (LOEC) of 2.4 ug/L and the no observed effect concentration (NOEC) of 0.80 ug/L, as determined in a 21 day toxicity study with the water flea, Daphnia magna. Threshold values (LOEC and NOEC) are from USEPA Office of Pesticide Programs Ecotoxicity database.
Guideline Reference: OPP Pesticide Ecotoxicity Database.
Guideline Reference: Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 81320, Ethoprop
Region 3     
Merrit Ditch
 
LOE ID: 55106
 
Pollutant: Ethoprop
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Ethoprop.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for Ethoprop is the maximum acceptable toxicant concentration (MATC) of 1.4 ug/L. The MATC (or Chronic Value as defined in USEPA 1985, P20 section F) is calculated as the geometric mean of the lowest observed effect concentration (LOEC) of 2.4 ug/L and the no observed effect concentration (NOEC) of 0.80 ug/L, as determined in a 21 day toxicity study with the water flea, Daphnia magna. Threshold values (LOEC and NOEC) are from USEPA Office of Pesticide Programs Ecotoxicity database.
Guideline Reference: OPP Pesticide Ecotoxicity Database.
Guideline Reference: Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
DECISION ID
82279
Region 3     
Merrit Ditch
 
Pollutant: Malathion
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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.

Six lines of evidence are available in the administrative record to assess this pollutant. Zero of the five samples exceed the evaluation guideline for aquatic life uses (Palumbo, A.J., et al., 2012) and zero of the five samples exceed the evaluation guideline for drinking water (National health advisory level (USEPA drinking water health advisory). This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information' unless the beneficial use is not supported.

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 CWA 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 Zero of the five samples exceed the evaluation guidelines 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.
 
Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 82279, Malathion
Region 3     
Merrit Ditch
 
LOE ID: 55110
 
Pollutant: Malathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Malathion.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the 4-day average concentration of Malathion does not exceed 0.028 ug/L.
Guideline Reference: Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82279, Malathion
Region 3     
Merrit Ditch
 
LOE ID: 55109
 
Pollutant: Malathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Malathion.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the 4-day average concentration of Malathion does not exceed 0.028 ug/L.
Guideline Reference: Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82279, Malathion
Region 3     
Merrit Ditch
 
LOE ID: 55111
 
Pollutant: Malathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial 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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Malathion.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the 4-day average concentration of Malathion does not exceed 0.028 ug/L.
Guideline Reference: Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82279, Malathion
Region 3     
Merrit Ditch
 
LOE ID: 55112
 
Pollutant: Malathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Malathion.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the 4-day average concentration of Malathion does not exceed 0.028 ug/L.
Guideline Reference: Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82279, Malathion
Region 3     
Merrit Ditch
 
LOE ID: 55107
 
Pollutant: Malathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Malathion.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The USEPA drinking water health advisory for malathion is 500 µg/L.
Guideline Reference: 2011 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82279, Malathion
Region 3     
Merrit Ditch
 
LOE ID: 55108
 
Pollutant: Malathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Malathion.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The USEPA drinking water health advisory for malathion is 500 µg/L.
Guideline Reference: 2011 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
DECISION ID
82280
Region 3     
Merrit Ditch
 
Pollutant: Methyl Parathion
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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.

Six lines of evidence are available in the administrative record to assess this pollutant. Zero of the five samples exceed the evaluation guideline for aquatic life uses (CDFW, 1992) and zero of the five samples exceed the evaluation guideline for drinking water (USEPA IRIS reference dose). This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information' unless the beneficial use is not supported.

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 CWA 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 Zero of the five samples exceed the evaluation guidelines 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.
 
Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 82280, Methyl Parathion
Region 3     
Merrit Ditch
 
LOE ID: 55115
 
Pollutant: Methyl Parathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Parathion, methyl.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The California Department of Fish and Game (now called the California Department of Fish and Wildlife) instantaneous criteria for Methyl Parathion is 0.08 ug/L.
Guideline Reference: Hazard Assessment of the Insecticide Methyl Parathion to Aquatic Organisms in the Sacramento River System
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82280, Methyl Parathion
Region 3     
Merrit Ditch
 
LOE ID: 55113
 
Pollutant: Methyl Parathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Parathion, methyl.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Based on USEPA IRIS reference dose (RfD) as a drinking water level, the drinking water health advisory level for Parathion, methyl is 1.8 µg/L. This was calculated assuming 70 kg body weight, 2 liters/day water consumption, and 20% relative source contribution from drinking water.  An additional uncertainty factor of 10 is used for Class C carcinogens.
Guideline Reference: IRIS Database Calculations (summary)
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82280, Methyl Parathion
Region 3     
Merrit Ditch
 
LOE ID: 55114
 
Pollutant: Methyl Parathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Parathion, methyl.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Based on USEPA IRIS reference dose (RfD) as a drinking water level, the drinking water health advisory level for Paration, methyl is 1.8 µg/L. This was calculated assuming 70 kg body weight, 2 liters/day water consumption, and 20% relative source contribution from drinking water.  An additional uncertainty factor of 10 is used for Class C carcinogens.
Guideline Reference: IRIS Database Calculations (summary)
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82280, Methyl Parathion
Region 3     
Merrit Ditch
 
LOE ID: 55118
 
Pollutant: Methyl Parathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Parathion, methyl.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The California Department of Fish and Game (now called California Department of Fish and Wildlife) instantaneous criteria for Methyl Parathion is 0.08 ug/L.
Guideline Reference: Hazard Assessment of the Insecticide Methyl Parathion to Aquatic Organisms in the Sacramento River System. California Department of Fish and Game. Environmental Services Division. Administrative Report 92-1
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82280, Methyl Parathion
Region 3     
Merrit Ditch
 
LOE ID: 55116
 
Pollutant: Methyl Parathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Parathion, methyl.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The California Department of Fish and Game (now called the California Department of Fish and Wildlife) instantaneous criteria for Methyl Parathion is 0.08 ug/L.
Guideline Reference: Hazard Assessment of the Insecticide Methyl Parathion to Aquatic Organisms in the Sacramento River System
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82280, Methyl Parathion
Region 3     
Merrit Ditch
 
LOE ID: 55117
 
Pollutant: Methyl Parathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial 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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Parathion, methyl.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The California Department of Fish and Game (now called California Department of Fish and Wildlife) instantaneous criteria for Methyl Parathion is 0.08 ug/L.
Guideline Reference: Hazard Assessment of the Insecticide Methyl Parathion to Aquatic Organisms in the Sacramento River System. California Department of Fish and Game. Environmental Services Division. Administrative Report 92-1
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
DECISION ID
82281
Region 3     
Merrit Ditch
 
Pollutant: Phorate
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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.

Six lines of evidence are available in the administrative record to assess this pollutant. Zero of the five samples exceed the evaluation guideline for aquatic life uses (USEPA Office of Pesticide Programs, 2011) and zero of the five samples exceed the evaluation guideline for drinking water (National Academy of Sciences health advisory level). This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information' unless the beneficial use is not supported.

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 CWA 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 Zero of the five samples exceed the evaluation guidelines 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.
 
Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 82281, Phorate
Region 3     
Merrit Ditch
 
LOE ID: 55131
 
Pollutant: Phorate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial 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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Phorate.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for Phorate is the median lethal concentration (LC50) of 2 ug/L, as determined in a 96 hour toxicity study of bluegill sunfish (Lepomis macrochirus) (USEPA Office of Pesticide Programs Ecotoxicity database).
Guideline Reference: OPP Pesticide Ecotoxicity Database.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82281, Phorate
Region 3     
Merrit Ditch
 
LOE ID: 55133
 
Pollutant: Phorate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Phorate.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for Phorate is the median lethal concentration (LC50; 2 ug/L). This is based on a 96 hour toxicity study of Bluegill sunfish (Lepomis macrochirus)
Guideline Reference: OPP Pesticide Ecotoxicity Database.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82281, Phorate
Region 3     
Merrit Ditch
 
LOE ID: 55136
 
Pollutant: Phorate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
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: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Phorate.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The national health advisory level for phorate is 0.7 µg/L. This was calculated using the no-adverse-effect dosage of 0.01 mg/kg, assuming 70 kg body weight, 2 liters/day water consumption, 20% relative source contribution from drinking water, and divided by 100 for a factor of safety.
Guideline Reference: National Academy of Sciences - Volume I Drinking Water and Health
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82281, Phorate
Region 3     
Merrit Ditch
 
LOE ID: 55134
 
Pollutant: Phorate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Phorate.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for Phorate is the median lethal concentration (LC50; 2 ug/L). This is based on a 96 hour toxicity study of Bluegill sunfish (Lepomis macrochirus)
Guideline Reference: OPP Pesticide Ecotoxicity Database.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82281, Phorate
Region 3     
Merrit Ditch
 
LOE ID: 55132
 
Pollutant: Phorate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Phorate.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The evaluation guideline for Phorate is the median lethal concentration (LC50) of 2 ug/L, as determined in a 96 hour toxicity study of bluegill sunfish (Lepomis macrochirus) (USEPA Office of Pesticide Programs Ecotoxicity database).
Guideline Reference: OPP Pesticide Ecotoxicity Database.
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 82281, Phorate
Region 3     
Merrit Ditch
 
LOE ID: 55135
 
Pollutant: Phorate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Phorate.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The National Academy of Sciences health advisory for phorate is 0.7 µg/L. This was calculated using the no-adverse-effect dosage of 0.01 mg/kg, assuming 70 kg body weight, 2 liters/day water consumption, 20% relative source contribution from drinking water, and divided by 100 for a factor of safety.
Guideline Reference: National Academy of Sciences - Volume I Drinking Water and Health
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
DECISION ID
75852
Region 3     
Merrit Ditch
 
Pollutant: Temperature, water
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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.

Two lines of evidence are available in the administrative record to assess this pollutant. Ten of the 64 samples exceed the evaluation guideline (Moyle, 1976) used to interpret the water quality objective for water temperature.

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 CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Ten of the 64 samples exceed the evaluation guideline 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.
 
Regional Board Decision 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.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 75852, Temperature, water
Region 3     
Merrit Ditch
 
LOE ID: 48389
 
Pollutant: Temperature, water
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 39
Number of Exceedances: 6
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 6 of 39 samples exceed the criterion for Water Temperature.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The optimum range for growth and completion of most life stages of rainbow trout is 13-21 degrees Celsius (Moyle 1976).
Guideline Reference: Inland Fishes of California
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-6/30/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 75852, Temperature, water
Region 3     
Merrit Ditch
 
LOE ID: 14504
 
Pollutant: Temperature, water
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold Freshwater Habitat
 
Number of Samples: 25
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 4 of 25 samples exceed the criterion for Water Temperature.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses (General Objective in 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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline: Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).
Guideline Reference: Inland Fishes of California
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
 
DECISION ID
75572
Region 3     
Merrit Ditch
 
Pollutant: pH
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Sources: A Source Unknown
Expected TMDL Completion Date: 2027
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA 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.

Ten lines of evidence are available in the administrative record to assess this pollutant. Five beneficial uses are assessed. Seven of the 61 samples exceed the water quality objective for Cold and Warm Freshwater Habitats, and 17 of the 61 samples exceed the water quality objectives for Drinking Water and Recreation.

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 CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Seven of the 61 samples exceed the water quality objective for Cold and Warm Freshwater Habitats 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.
 
Regional Board Decision 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.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 75572, pH
Region 3     
Merrit Ditch
 
LOE ID: 48364
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 36
Number of Exceedances: 5
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 5 of 36 samples exceed the criterion for pH.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The pH value shall not be depressed below 7.0 or raised above 8.5 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 75572, pH
Region 3     
Merrit Ditch
 
LOE ID: 14755
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold Freshwater Habitat
 
Number of Samples: 25
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 2 of 25 samples exceed the criterion for pH.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 75572, pH
Region 3     
Merrit Ditch
 
LOE ID: 14756
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 25
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 4 of 25 samples exceed the criterion for pH.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 75572, pH
Region 3     
Merrit Ditch
 
LOE ID: 48375
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 36
Number of Exceedances: 13
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 13 of 36 samples exceed the criterion for pH.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The pH value shall not be depressed below 6.5 or raised above 8.3 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 75572, pH
Region 3     
Merrit Ditch
 
LOE ID: 14758
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 25
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 4 of 25 samples exceed the criterion for pH.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 75572, pH
Region 3     
Merrit Ditch
 
LOE ID: 48377
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 36
Number of Exceedances: 13
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 13 of 36 samples exceed the criterion for pH.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The pH value shall neither be depressed below 6.5 nor raised above 8.3 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 75572, pH
Region 3     
Merrit Ditch
 
LOE ID: 48378
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 36
Number of Exceedances: 5
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 5 of 36 samples exceed the criterion for pH.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The pH value shall not be depressed below 7.0 or raised above 8.5 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 75572, pH
Region 3     
Merrit Ditch
 
LOE ID: 14501
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 25
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 2 of 25 samples exceed the criterion for pH.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 75572, pH
Region 3     
Merrit Ditch
 
LOE ID: 48376
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 36
Number of Exceedances: 13
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 13 of 36 samples exceed the criterion for pH.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The pH value shall neither be depressed below 6.5 nor raised above 8.3 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 1/30/2007-3/31/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 75572, pH
Region 3     
Merrit Ditch
 
LOE ID: 14757
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 25
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch to determine beneficial use support and results are as follows: 4 of 25 samples exceed the criterion for pH.
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 1/26/2005-12/12/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
 
DECISION ID
80389
Region 3     
Merrit Ditch
 
Pollutant: Diazinon
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)(2016)
Revision Status Original
Sources: Agriculture
TMDL Name: Lower Salinas River Chlorpyrifos and Diazinon TMDL
TMDL Project Code: 133
Date TMDL Approved by USEPA: 10/07/2011
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: 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.

Five lines of evidence are available in the administrative record to assess this pollutant. The decision for the 2010 303(d) list used 0.16 ug/L (Siepmann and Finlayson, 2000) as the evaluation guideline and resulted in zero out of two samples exceeding this guideline. However, 0.1 ug/L is now being used as the evaluation guideline set to protect for aquatic life beneficial uses (Finlayson, 2004), which results in one out of two samples exceeding the evaluation guideline. New samples were evaluated during this listing cycle, and when combined with 2010 listing cycle data, two out of five samples exceeding the evaluation guideline. Zero of the three samples exceed the USEPA drinking water health advisory. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported using table 3.1.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification to place it in the Being Addressed portion of the 303(d) list. In accordance with section 2.2 of the Policy there is sufficient justification to place it in the Being Addressed portion of the 303(d) list because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.

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 five samples exceed the evaluation guideline (Finlayson, 2004) set to protect for aquatic life beneficial uses and these exceed the allowable frequency listed in Table 4.1 of the Listing Policy.

4. The Lower Salinas River Watershed Chlorpyrifos and Diazinon TMDL has been approved by the USEPA on October 7, 2011.

5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision 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.

Furthermore, this pollutant waterbody combination should be placed in the 'Being Addressed' portion of the 303(d) list because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 80389, Diazinon
Region 3     
Merrit Ditch
 
LOE ID: 55156
 
Pollutant: Diazinon
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: State Water Board staff assessed CMP data for Merrit Ditch to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Diazinon.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The USEPA drinking water health advisory for diazinon is 1 µg/L.
Guideline Reference: 2011 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ Merritt Ditch - 309MER]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 80389, Diazinon
Region 3     
Merrit Ditch
 
LOE ID: 15129
 
Pollutant: Diazinon
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold 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 CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch 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: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 Control Plan (Basin Plan) - Central Coast Region (Region 3)
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
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 80389, Diazinon
Region 3     
Merrit Ditch
 
LOE ID: 48396
 
Pollutant: Diazinon
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 1 of 3 samples exceed the criterion for Diazinon.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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 Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (Finlayson, 2004).
Guideline Reference: Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 80389, Diazinon
Region 3     
Merrit Ditch
 
LOE ID: 48397
 
Pollutant: Diazinon
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Water Board Staff assessed public submissions data for Merrit Ditch to determine beneficial use support and results are as follows: 1 of 3 samples exceed the criterion for Diazinon.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
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 Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (Finlayson, 2004).
Guideline Reference: Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game
 
Spatial Representation: Data for this line of evidence for Merrit Ditch was collected at 1 monitoring site [ 309MER - Merritt Ditch above Highway 183]
Temporal Representation: Data was collected over the time period 2/14/2007-9/25/2007.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
Line of Evidence (LOE) for Decision ID 80389, Diazinon
Region 3     
Merrit Ditch
 
LOE ID: 15130
 
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 CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Merritt Ditch 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: Central Coast Water Quality Preservation Inc toxicity data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
 
SWAMP Data: Non-SWAMP
 
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 Control Plan (Basin Plan) - Central Coast Region (Region 3)
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
 
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 Merritt Ditch was collected at 1 monitoring site [ 309MER - Merrit Ditch upstream Highway 183]
Temporal Representation: Data was collected over the time period 8/23/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (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 Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):