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

# Supporting Information

## Regional Board 3 - Central Coast Region

Water Body Name: | Oso Flaco Creek
Water Body ID: | CAR3121003020020124122144
Water Body Type: | River & Stream

DECISION ID | 4855
Pollutant: | Ammonia (Unionized)
Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2006)
Revision Status | Revised
Sources: | Agriculture | Unknown Nonpoint Source
Expected TMDL Completion Date: | 2013
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for removal from the section 303(d) list under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. Two lines of evidence are assessed: LOE #1974 is disregarded and replaced by LOE #9658 because LOE #9658 contains all of the information in LOE #1974, as well as additional information collected monthly between January 2001 and March 2001. LOE #1974 is not included in the current assessment. Two lines of evidence are used in this current assessment. Twelve of 37 samples exceed the General Water Quality Objective as it applies to Aquatic Life Beneficial Uses. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Twelve of 37 samples exceed the General Water Quality Objective as it applies to Aquatic Life Beneficial Uses and this exceeds the allowable frequency calculated from the equation in Table 4.1 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.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4855

LOE ID: | 9658
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: | 14
Number of Exceedances: | 10
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 10 of 14 samples exceed the criterion for Ammonia as N, Unionized.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin General Objective, Chapter III, Section II.A.2 (General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries) states that the discharge of wastes shall not cause concentrations of unionized ammonia (NH3) to exceed 0.025 mg/l (as N) in receiving waters (page III-4) .
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road].
Temporal Representation: | Data was collected over the time period 2/3/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 14323
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: | 23
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 2 of 23 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
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin General Objective, Chapter III, Section II.A.2 (General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries) states that the discharge of wastes shall not cause concentrations of unionized ammonia (NH3) to exceed 0.025 mg/l (as N) in receiving waters (page III-4) .
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-12/14/2006. 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):
LOE ID: | 1974
Pollutant: | Ammonia (Unionized)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Wildlife Habitat
Number of Samples: | 12
Number of Exceedances: | 9
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Levels of unionized ammonia greater than the general numeric water quality objective of 0.025 mg/l (CCAMP, 2004; SWAMP, 2004). Nine of 12 data points exceed the water quality objective.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | The discharge of wastes shall not cause concentrations of unionized ammonia (NH3) to exceed 0.025 mg/L (as N) in receiving waters (Region 3 Basin Plan, Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a. General Objectives, page III-4).
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data were collected at site 312OFC on Oso Flaco Creek, in San Luis Obispo County.
Temporal Representation: | Samples were collected from February 2000 to January 2001.
Environmental Conditions: | Water body is located in the Santa Maria hydrologic unit, Guadalupe hydrologic subarea. Monitoring site is located at Oso Flaco Creek at Oso Flaco Lake Road (#312OFC).
QAPP Information: | CCAMP, SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 6561
Pollutant: | Fecal Coliform
Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2006)
Revision Status | Revised
Sources: | Agriculture | Natural Sources | Source Unknown
Expected TMDL Completion Date: | 2013
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for removal from the section 303(d) list under section 4.3 of the Listing Policy. Under section 4.3 a single line of evidence is necessary to assess delisting status. Three lines of evidence are available in the administrative record to assess this pollutant. Two lines of evidence are assessed: LOE #3977 is disregarded as it is a placeholder for a listing made prior to 2006. No data or information is associated with this LOE. However, LOE #11843 contains all the data and information used to determine listing status for the water segment-pollutant combination. Two lines of evidence are assessed in this decision. Seven of 16 samples exceed the Water Contact Recreation water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Seven of 16 samples exceed the Water Contact Recreation water quality objective and this exceeds the allowable frequency calculated from the equation 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.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
SWRCB Board Decision / Staff Recommendation: | N/A
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 6561

LOE ID: | 3977
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Not Recorded
Beneficial Use: | Water Contact Recreation
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: | Placeholder reference pre-2006 303(d)
Water Quality Objective/Criterion: | Unspecified
Objective/Criterion Reference: | Placeholder reference pre-2006 303(d)
Evaluation Guideline: | Unspecified
Guideline Reference: | Placeholder reference pre-2006 303(d)
Spatial Representation: | Unspecified
Temporal Representation: | Unspecified
Environmental Conditions: | Unspecified
QAPP Information: | Unspecified
QAPP Information Reference(s):
LOE ID: | 11843
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 16
Number of Exceedances: | 7
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 7 of 16 samples exceed the criterion for Coliform, Fecal.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for water contact recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 200 MPN/100 ml, nor shall more than ten percent of total samples during any 30-day period exceed 400 MPN/100 ml.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 1/12/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11844
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 16
Number of Exceedances: | 2
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 2 of 16 samples exceed the criterion for Coliform, Fecal.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 2000/100 ml, nor shall more than ten percent of samples collected during any 30-day period exceed 4000/100 ml.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 1/12/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 6857
Pollutant: | Nitrate
Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list)(2006)
Revision Status | Revised
Sources: | Agriculture | Groundwater Loadings
Expected TMDL Completion Date: | 2013
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for removal from the section 303(d) list under section 4.1 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. Seven LOEs are used to assess three Beneficial Uses. Note that LOE #1975 is disregarded and replaced by LOE #9643 because LOE #9643 contains all of the information in LOE #1975 , as well as two additional months of data collected February 2001 and March 2001. LOE #1975 is not included in the current assessment. Three lines of evidence are use to assess the Municipal and Domestic Supply Beneficial Use. Twenty-two of 22 samples exceed the Municipal and Domestic Supply water quality objective for Nitrate. In addition, 18 of 18 samples (analyzed for Nitrate + Nitrite) exceed the OEHHA public Health Goal in Drinking Water (December 1997) as it applies to the Municipal and Domestic Supply Beneficial Use. Two lines of evidence are use to assess the Agriculture Supply Beneficial Use. Sixteen of the 22 samples exceed the objective for Agricultural Supply. Two lines of evidence are use to assess the both Cold and Warm Freshwater Habitat Beneficial Uses. All 22 samples exceeded the Numeric Nutrient Endpoint for Nitrate in the Central Coast Region, set to protect aquatic life beneficial uses. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Twenty-two of 22 samples exceed the Municipal and Domestic Supply water quality objective for Nitrate and 18 of 18 samples (analyzed for Nitrate + Nitrite) exceed the OEHHA public Health Goal in Drinking Water (December 1997) as it applies to the Municipal and Domestic Supply beneficial use. Each of these exceeds the allowable frequency calculated from the equation in Table 4.1 of the Listing Policy. 4. Sixteen of the 22 samples exceed the objective for Agricultural Supply and this exceeds the allowable frequency calculated from the equation in Table 4.1 of the Listing Policy. 5. All 22 samples exceeded the Numeric Nutrient Endpoint for Nitrate in the Central Coast Region, set to protect aquatic life beneficial uses and this exceeds the allowable frequency calculated from the equation in Table 4.1 of the Listing Policy. 6. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be removed from on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 6857

LOE ID: | 14303
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 5
Number of Exceedances: | 5
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 5 of 5 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
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin Objective for municipal and domestic supply uses of inland surface waters (Section II.A.2) states the following: waters shall not contain concentrations of chemical constituents in excess of the limits specified in California Code of Regulations, Title 22, Article 4, Chapter 15, Section 64435, Tables 2 and 3 as listed in Table 3-2. The maximum contaminant level listed in Table 3-2 (inorganic and fluoride concentrations not to be exceeded in domestic or municipal supply) for nitrate is 10.0 mg/L (NO3 as N).
Objective/Criterion Reference: | Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
| Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-11/29/2005. 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):
LOE ID: | 1975
Pollutant: | Nitrate as Nitrate (NO3)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 15
Number of Exceedances: | 15
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Fifteen out of 15 samples exceeded the water quality objective for nitrate (as NO3) for municipal and domestic supply (CCAMP, 2004; SWAMP, 2004).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | 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 (Region 3 Basin Plan, p III-3; In Table 3-2, the MCL for Nitrate (as NO3) in Domestic or Municipal Supply is 45 mg/L).
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples collected from one site.
Temporal Representation: | Samples were collected from February 2000 to March 2001.
Environmental Conditions: | The water body is located in the Santa Maria hydrologic unit, Guadalupe hydrologic area, Guadalupe hydrologic subarea. The site is located at Little Oso Flaco Creek (312 OFN) and is tributary to Oso Flaco Creek.
QAPP Information: | CCAMP, SWAMP QAPP.
QAPP Information Reference(s):
LOE ID: | 9643
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 17
Number of Exceedances: | 12
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 12 of 17 samples exceed the criterion for Nitrate as N.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when nitrate exceeds 30 mg/L NO3 as N in irrigation supply water.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 1/12/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 9656
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 17
Number of Exceedances: | 17
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 17 of 17 samples exceed the criterion for Nitrate as N.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin Objective for municipal and domestic supply uses of inland surface waters (Section II.A.2) states the following: waters shall not contain concentrations of chemical constituents in excess of the limits specified in California Code of Regulations, Title 22, Article 4, Chapter 15, Section 64435, Tables 2 and 3 as listed in Table 3-2. The maximum contaminant level listed in Table 3-2 (inorganic and fluoride concentrations not to be exceeded in domestic or municipal supply) for nitrate is 10.0 mg/L (NO3 as N).
Objective/Criterion Reference: | Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
| Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 1/12/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 14302
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 5
Number of Exceedances: | 4
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 4 of 5 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
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when nitrate exceeds 30 mg/L NO3 as N in irrigation supply water.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-11/29/2005. 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):
LOE ID: | 15217
Pollutant: | Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 18
Number of Exceedances: | 18
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 18 of 18 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
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 Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 3/22/2005-12/14/2006. 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):
LOE ID: | 27880
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 5
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 Southern Area Ag-Waiver Monitoring (R3_CMPSouth)
Data Reference: | Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
Water Quality Objective/Criterion: | Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect beneficial uses (general objective for biostimulatory substances, Water Quality Control Plan, Central Coast Basin, Chapter III, Section II).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
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
| Technical Paper - Interpreting Narrative Objectives for Biostimulatory Substances Using the Technical Approach for Developing California Nutrient Numeric Endpoints. Central Coast Region
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-11/29/2005. 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):
LOE ID: | 27881
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 17
Number of Exceedances: | 17
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Data for this assessment unit was collected by one monitoring project: CCAMP Santa Maria (SantaMaria)
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect beneficial uses (general objective for biostimulatory substances, Water Quality Control Plan, Central Coast Basin, Chapter III, Section II).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
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
| Technical Paper - Interpreting Narrative Objectives for Biostimulatory Substances Using the Technical Approach for Developing California Nutrient Numeric Endpoints. Central Coast Region
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 1/12/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 14767
Pollutant: | Boron
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the 17 samples exceed the Agricultural Supply water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. However, there are an insufficient number of samples to make a "use rating" decision. Central Coast Water Board staff require a minimum of 26 samples to make a "use rating" decision of Fully Supporting. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of the 17 samples exceed the Agricultural Supply water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14767

LOE ID: | 9640
Pollutant: | Boron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Agricultural Supply
Number of Samples: | 13
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 13 samples exceed the criterion for Boron, dissolved.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. In addition, waters used for irrigation and livestock watering shall not exceed concentrations for those chemicals listed in Table 3.4 (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). Table 3-4 (page III-9) lists the maximum concentration for boron for irrigation supply is 0.75 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 1/12/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 9659
Pollutant: | Boron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 4
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 4 samples exceed the criterion for Boron.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. In addition, waters used for irrigation and livestock watering shall not exceed concentrations for those chemicals listed in Table 3.4 (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). Table 3-4 (page III-9) lists the maximum concentration for boron for irrigation supply is 0.75 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 4/10/2000-6/26/2000. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 14771
Pollutant: | Chlorophyll-a
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. One of the 39 samples exceed the Evaluation Guideline (North Carolina Administrative code, Title 15A) and the General Water Quality Objective set to protect aquatic life beneficial uses. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of the 39 samples exceed the Evaluation Guideline (North Carolina Administrative code, Title 15A) and the General Water Quality Objective set to protect aquatic life beneficial uses and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14771

LOE ID: | 14324
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: | 22
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 22 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
Water Quality Objective/Criterion: | Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect beneficial uses (general objective for biostimulatory substances, Water Quality Control Plan, Central Coast Basin, Chapter III, Section II).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
| North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards
| Water quality standards table
Evaluation Guideline: | North Carolina Administrative code (NCAC), Title 15A - Environmental and Natural Resources, Subchapter 2B-Surface water and wetland standards, Rule 0211-Fresh surface water quality standards for class C waters (Class C is defined as freshwaters protected for secondary recreation, fishing, aquatic life including propagation and survival, and wildlife). Section 3(a) of Rule 0211 applies to all fresh surface waters and states that chlorophyll a is not to exceed 40 ug/L.
Guideline Reference: | North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards
| North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-12/14/2006. 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):
LOE ID: | 9642
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: | 17
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 1 of 17 samples exceed the criterion for Chlorophyll a.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect beneficial uses (general objective for biostimulatory substances, Water Quality Control Plan, Central Coast Basin, Chapter III, Section II).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
| North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards
| Water quality standards table
Evaluation Guideline: | North Carolina Administrative code (NCAC), Title 15A - Environmental and Natural Resources, Subchapter 2B-Surface water and wetland standards, Rule 0211-Fresh surface water quality standards for class C waters (Class C is defined as freshwaters protected for secondary recreation, fishing, aquatic life including propagation and survival, and wildlife). Section 3(a) of Rule 0211 applies to all fresh surface waters and states that chlorophyll a is not to exceed 40 ug/L.
Guideline Reference: | North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards
| North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 1/12/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 14773
Pollutant: | Chlorpyrifos
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. One of the 2 samples exceed the Evaluation Guideline (Sipmann and Finlayson, 2000) applied to protect for aquatic life beneficial uses. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. However, there are an insufficient number of samples to make a "use rating" decision. Central Coast Water Board staff require a minimum of 16 samples to make a "use rating" decision of Fully Supporting. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of the 2 samples exceed the Evaluation Guideline (Sipmann and Finlayson, 2000) applied to protect for aquatic life beneficial uses and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14773

LOE ID: | 15267
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: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 1 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
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
| Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | One hour average maximum concentration 0.025 ug/L as stated in Sipmann and Finlayson (2000).
Guideline Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 8/23/2006-9/26/2006. 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 | 14775
Pollutant: | Diazinon
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Neither of the 2 samples exceed the Evaluation Guideline (Sipmann and Finlayson, 2000) applied to protect for aquatic life beneficial uses. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. However, there are an insufficient number of samples to make a "use rating" decision. Central Coast Water Board staff require a minimum of 16 samples to make a "use rating" decision of Fully Supporting. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Neither of the 2 samples exceed the Evaluation Guideline (Sipmann and Finlayson, 2000) applied to protect for aquatic life beneficial uses and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14775

LOE ID: | 15268
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 Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek 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
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
| Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | One hour average maximum concentration 0.16 ug/L as stated in Sipmann and Finlayson (2000).
Guideline Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 8/23/2006-9/26/2006. 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 | 14777
Pollutant: | Electrical Conductivity
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the 17 samples exceed the Agricultural Supply water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of the 17 samples exceed the Agricultural Supply water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14777

LOE ID: | 11845
Pollutant: | Electrical Conductivity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 14
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 14 samples exceed the criterion for Conductivity(Us).
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when conductivity exceeds 3.0 mS/cm in irrigation supply water.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/3/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11865
Pollutant: | Electrical Conductivity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Conductivity(Us).
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when conductivity exceeds 3.0 mS/cm in irrigation supply water.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/6/2000. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 14776
Pollutant: | Low Dissolved Oxygen
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Six lines of evidence are available in the administrative record to assess these pollutants. Two water quality objectives are assessed: None of the 42 samples exceed the dissolved oxygen water quality objective for Warm Freshwater Habitat and Nine of the 42 samples exceed the general water quality objective for oxygen saturation (when applied as a single sample maximum). However, the Basin Plan objective states that the median oxygen saturation value shall not fall below 85% and the median value did not exceed this criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Two water quality objectives are assessed: None of the 42 samples exceed the dissolved oxygen water quality objective for Warm Freshwater Habitat and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. In addition, the median value did not exceed the General Objective. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14776

LOE ID: | 14326
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: | 23
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 1 of 23 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
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: Median values should not fall below 85% saturation as a result of controllable water quality conditions.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-12/14/2006. 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):
LOE ID: | 14325
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: | 23
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 23 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
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-12/14/2006. 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):
LOE ID: | 13408
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: | 16
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 16 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/3/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 13425
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: | 3
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/6/2000. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 13409
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: | 16
Number of Exceedances: | 5
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 5 of 16 samples exceed the criterion for Oxygen, Saturation.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: Median values should not fall below 85% saturation as a result of controllable water quality conditions.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/3/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 13426
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: | 3
Number of Exceedances: | 3
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 3 of 3 samples exceed the criterion for Oxygen, Saturation.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: Median values should not fall below 85% saturation as a result of controllable water quality conditions.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/6/2000. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 14765
Pollutant: | Nitrogen, ammonia (Total Ammonia)
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollution
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. One of the 39 samples exceed the Evaluation Guideline (EPA's Lifetime Health advisory level, 2006) applied to protect the Municipal & Domestic Supply beneficial use. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of the 39 samples exceed the Evaluation Guideline (EPA's Lifetime Health advisory level, 2006) applied to protect the Municipal & Domestic Supply beneficial use and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14765

LOE ID: | 9627
Pollutant: | Ammonia as Nitrogen
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 17
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 1 of 17 samples exceed the criterion for Ammonia as N, Total.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | USEPA Health Advisory 2006 Edition of the Drinking Water Standards and Health Advisories (EPA 822-R-06-013, 2006).
Objective/Criterion Reference: | 2006 edition of the drinking water standards and health advisories. EPA 822-R-03-013
Evaluation Guideline: | EPA's Lifetime Health advisory level for total ammonia is 30.0 mg/L as stated on page 8 of the 2006 edition of the drinking water standards and health advisories. This Advisory Level is defined as "the concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for up to ten days of exposure."
Guideline Reference: | 2006 edition of the drinking water standards and health advisories. EPA 822-R-03-013
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 1/12/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 14304
Pollutant: | Ammonia as Nitrogen
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 22
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 22 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
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 Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-12/14/2006. 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 | 14787
Pollutant: | Salinity
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. None of the 40 samples exceed the Agricultural Supply water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of the 40 samples exceed the Agricultural Supply water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14787

LOE ID: | 13423
Pollutant: | Salinity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 14
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 14 samples exceed the criterion for Salinity.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when salinity exceeds 3.0 ppt in irrigation supply water.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/3/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 13427
Pollutant: | Salinity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Salinity.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when salinity exceeds 3.0 ppt in irrigation supply water.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/6/2000. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 14356
Pollutant: | Salinity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 23
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 23 samples exceed the criterion for Salinity.
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
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when salinity exceeds 3.0 ppt in irrigation supply water.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-12/14/2006. 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 | 14789
Pollutant: | Turbidity
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under sections 2.1 and 3.2 of the Listing Policy. Three lines of evidence are available in the administrative record to assess this pollutant. Based on section 3.2 the site exceeded numeric objectives for conventional pollutants. According to the binomial distribution, waters shall be placed on the section 303(d) list if the number of measured exceedances supports rejection of the null hypothesis as presented in Table 3.2. Thirty-five of 35 samples exceeded the Evaluation Guideline (Sigler et al., 1984) applied to protect for aquatic life beneficial uses and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. However, this guideline is not relevant for Oso Flaco Creek because staff are not aware of any documentation of steelhead populations is the watershed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. This guideline is not relevant for Little Oso Flaco Creek because staff are not aware of any documentation of steelhead populations is the watershed. . 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because this guideline is not relevant for Little Oso Flaco Creek because staff are not aware of any documentation of steelhead populations is the watershed.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14789

LOE ID: | 13424
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 9
Number of Exceedances: | 9
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 9 of 9 samples exceed the criterion for Turbidity(NTU).
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Sigler et al. (1984) states that turbidities of 25 NTU's or greater caused reduction in juvenile salmonid growth due to interference with their ability to find food.
Guideline Reference: | Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 4/10/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 13442
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 3
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 3 of 3 samples exceed the criterion for Turbidity(NTU).
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Sigler et al. (1984) states that turbidities of 25 NTU's or greater caused reduction in juvenile salmonid growth due to interference with their ability to find food.
Guideline Reference: | Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/6/2000. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 14357
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 23
Number of Exceedances: | 23
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 23 of 23 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
Water Quality Objective/Criterion: | Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Sigler et al. (1984) states that turbidities of 25 NTU's or greater caused reduction in juvenile salmonid growth due to interference with their ability to find food.
Guideline Reference: | Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-12/14/2006. 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 | 14790
Pollutant: | pH
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Fifteen lines of evidence are available in the administrative record to assess this pollutant. One of 41 samples exceed the Agricultural Supply water quality objective, None of the 41 samples exceed the Warm Freshwater Habitat water quality objective and 2 of 41 samples exceed the numeric objective for Municipal & Domestic Supply, Non-Contact Recreation and Water Contact Recreation. 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. One of 41 samples exceed the Agricultural Supply water quality objective, None of the 41 samples exceed the Warm Freshwater Habitat water quality objective and 2 of 41 samples exceed the numeric objective for Municipal & Domestic Supply, Non-Contact Recreation and Water Contact Recreation. None of these exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14790

LOE ID: | 11846
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 15
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 1 of 15 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when pH is greater than 8.4 or less than 6.5 in irrigation supply water.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/3/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 14343
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 23
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 23 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
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-12/14/2006. 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):
LOE ID: | 14342
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 23
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 23 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
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-12/14/2006. 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):
LOE ID: | 14341
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 23
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 23 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
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for water contact recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-12/14/2006. 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):
LOE ID: | 14340
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 23
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 23 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
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin, Section II.A.2. Municipal and Domestic Supply Objectives, Section II.A.2.a states the following: The pH value shall neither be depressed below 6.5 or raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-12/14/2006. 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):
LOE ID: | 14339
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 23
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 23 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
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when pH is greater than 8.4 or less than 6.5 in irrigation supply water.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-12/14/2006. 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):
LOE ID: | 11862
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 15
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 2 of 15 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for water contact recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/3/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11864
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 15
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 15 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/3/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11861
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 15
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 2 of 15 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin, Section II.A.2. Municipal and Domestic Supply Objectives, Section II.A.2.a states the following: The pH value shall neither be depressed below 6.5 or raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/3/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11863
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 15
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 2 of 15 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/3/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11586
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life 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 Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/6/2000. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11585
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/6/2000. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11584
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for water contact recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/6/2000. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11583
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
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: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin, Section II.A.2. Municipal and Domestic Supply Objectives, Section II.A.2.a states the following: The pH value shall neither be depressed below 6.5 or raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/6/2000. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 11582
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when pH is greater than 8.4 or less than 6.5 in irrigation supply water.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/6/2000. Diurnal monitoring conducted in summer months at all CCAMP monitoring sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 14769
Pollutant: | Chloride
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture | Source Unknown
Expected TMDL Completion Date: | 2013
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under sections 2.1 and 3.2 of the Listing Policy. One line of evidence is available in the administrative record to assess this pollutant. Based on section 3.2 the site exceeded numeric objectives for conventional pollutants. According to the binomial distribution, waters shall be placed on the section 303(d) list if the number of measured exceedances supports rejection of the null hypothesis as presented in Table 3.2. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Five of 17 samples exceeded the water quality objective for Agricultural Supply and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14769

LOE ID: | 9641
Pollutant: | Chloride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 17
Number of Exceedances: | 5
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 5 of 17 samples exceed the criterion for Chloride.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when chloride exceeds 106 mg/L in irrigation supply water.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 1/12/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 14780
Pollutant: | Sediment Toxicity
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture | Unknown Nonpoint Source
Expected TMDL Completion Date: | 2013
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under section 3.6 a single line of evidence is necessary to assess listing status for toxicity. Two lines of evidence are available in the administrative record to assess this pollutant in sediment samples. Both of the 2 samples were toxic to invertebrate test organisms (exhibited a significant increase in mortality compared to the laboratory control) and therefore exceed the narrative General Objective for toxicity, set to protect for aquatic life beneficial uses. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Both of the 2 samples were toxic to invertebrate test organisms and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14780

LOE ID: | 24604
Pollutant: | Invertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Sediment
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 1
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPsouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 1 of 1 samples exceed the criterion for Toxicity, Hyalella azteca 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
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected on a single day 4/19/2005. 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):
LOE ID: | 24603
Pollutant: | Invertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Sediment
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 1
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPsouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 1 of 1 samples exceed the criterion for Toxicity, Hyalella azteca Survival (%) 10 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
Data Reference: | Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
| Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected on a single day 5/15/2006. 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 | 14788
Pollutant: | Sodium
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture | Unknown Nonpoint Source
Expected TMDL Completion Date: | 2013
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under sections 2.1 and 3.2 of the Listing Policy. One line of evidence is available in the administrative record to assess this pollutant. Based on section 3.2 the site exceeded numeric objectives for conventional pollutants. According to the binomial distribution, waters shall be placed on the section 303(d) list if the number of measured exceedances supports rejection of the null hypothesis as presented in Table 3.2. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Sixteen of 17 samples exceeded the water quality objective for Agricultural Supply and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14788

LOE ID: | 9657
Pollutant: | Sodium
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 17
Number of Exceedances: | 16
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 16 of 17 samples exceed the criterion for Sodium.
Data Reference: | Final Data File used for assessment: CCAMP Water Quality Data_file1
| Final Data File used for assessment: CCAMP Water Quality Data_file2
| Final Data File used for assessment: CCAMP Water Quality Data_file3
Water Quality Objective/Criterion: | Waters shall not contain concentrations of chemical constituents in amounts which adversely affect the agricultural beneficial use. Interpretation of adverse effect shall be as derived from the University of California Agricultural Extension Service guidelines provided in Table 3-3 (Central Coast Waterboard Basin Plan, Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries). In Table 3-3 of the Basin Plan (page III-8), water quality guidelines state that severe problems may occur when sodium exceeds 69 mg/L in irrigation supply water.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 1/12/2000-3/1/2001. Santa Maria watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year. Toxicity monitoring is conducted twice during the rotation year (winter and summer) at a subset of sites.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 15448
Pollutant: | Unknown Toxicity
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture | Unknown Nonpoint Source
Expected TMDL Completion Date: | 2013
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 and section 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant in water samples. Four of the samples were toxic to test organisms (exhibited a significant increase in mortality or decrease in cell density compared to the laboratory control) and therefore exceed the narrative General Objective for toxicity, set to protect for aquatic life beneficial uses. The following is a summary of the results from individual toxicity tests. One of the 6 samples (tested for toxicity to plants), exceed the narrative General Objective for toxicity and none of the 5 samples (tested for toxicity to vertebrate test organisms), exceed the narrative General Objective for toxicity. However, 3 of the 7 samples (tested for toxicity to invertebrate test organisms), exceed the narrative General Objective for toxicity and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Three of the 7 samples (tested for toxicity to invertebrate test organisms), exceed the narrative General Objective for toxicity and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 15448

LOE ID: | 24616
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: | 1
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPsouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 1 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
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Significant reduction in cell count of test organism relative to the control (alpha < 0.05) and cell count <80% of control.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-9/26/2006. 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):
LOE ID: | 24615
Pollutant: | Vertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPsouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 0 of 5 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
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 2/21/2005-9/26/2006. 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):
LOE ID: | 24591
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: | 3
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPsouth) data for Oso Flaco Creek to determine beneficial use support and results are as follows: 3 of 7 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
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for Oso Flaco Creek was collected at 1 monitoring site [ 312OFC-Oso Flaco Creek at Oso Flaco Lake Road]
Temporal Representation: | Data was collected over the time period 7/26/2005-2/23/2006. 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):