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

# Supporting Information

## Regional Board 3 - Central Coast Region

Water Body Name: | Orcutt Creek
Water Body ID: | CAR3121003020011129154708
Water Body Type: | River & Stream

DECISION ID | 4601
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 | Grazing-Related Sources | Other Urban Runoff
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. Four lines of evidence (LOEs) are available in the administrative record to assess this pollutant. Two LOEs (#1927 and #1926) were the basis of the original decision to place this water segment-pollutant combination on the Section 303(d) list. However, It should be noted that these two LOEs contain overlapping data (collected by CCAMP staff at 3 sites in Orcutt Creek monthly between January 2000 and March 2001) and should not be additive. In addition, a new LOE (#9736) contains all the original CCAMP data from the 3 Orcutt Creek sites and therefore replaces both LOEs #1927 and #1926. Two LOEs are assessed in this decision (LOE # 9736 and #14425). Twenty of 84 samples exceed the General water quality objective as it applies to the Cold Freshwater Habitat beneficial use. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against 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 of 84 samples exceed the General water quality objective as it applies to the Cold Freshwater Habitat beneficial use 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 4601

LOE ID: | 9738
Pollutant: | Ammonia (Unionized)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 36
Number of Exceedances: | 8
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 Orcutt Creek to determine beneficial use support and results are as follows: 8 of 36 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1].
Temporal Representation: | Data was collected over the time period 2/3/2000-4/6/2001. 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: | 1926
Pollutant: | Ammonia (Unionized)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 23
Number of Exceedances: | 8
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | From new listing proposal: Regional Board staff is proposing that multiple water bodies (including Orcutt Solomon Creek) within the Santa Maria watershed be listed for unionized ammonia. The impairment is evidenced by levels of unionized ammonia greater than the general numeric water quality objective of 0.025 mg/l. The Regional Board assessed CCAMP data and results are as follows for two sites on Orcutt Solomon Creek: 3 of 11 and 5 of 12 data points exceed the criterion. See CCAMP data for further information (CCAMP, 2004). This constituent was not included in the last (2002) data evaluation because data had not been processed in time to meet the 2002 deadline.
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 sites 312ORB and 312ORI on Orcutt Solomon Creek, in Santa Barbara County.
Temporal Representation: | Unknown - see CCAMP data.
Environmental Conditions: |
QAPP Information: | Samples were taken according to CCAMP protocols.
QAPP Information Reference(s):
LOE ID: | 1927
Pollutant: | Ammonia (Unionized)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 36
Number of Exceedances: | 7
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Seven out of 36 samples exceeded the water quality objective (SWAMP, 2004).
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: | Samples were collected from three sites. Exceedances were detected in water samples collected from all sites.
Temporal Representation: | Samples were collected from January 2000 to April 2001.
Environmental Conditions: | The water body is located in the Santa Maria hydrologic unit, Guadalupe hydrologic subarea, Orcutt Creek planning watershed. Monitoring sites are located at Orcutt Solomon Creek at Black Road (#312ORB), Orcutt Solomon Creek upstream Santa Maria River (#312ORC) and Orcutt Solomon Creek at Highway 1 (312ORI).
QAPP Information: | SWAMP QAPP.
QAPP Information Reference(s):
LOE ID: | 14425
Pollutant: | Ammonia (Unionized)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 48
Number of Exceedances: | 12
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 Orcutt Creek to determine beneficial use support and results are as follows: 12 of 48 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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 | 4602
Pollutant: | Chlorpyrifos
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 | Other Urban Runoff | 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 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. The single sediment sample exceed the General water quality objective set to protect Aquatic Life beneficial uses. In addition, 12 of 13 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 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 13 samples exceed the Evaluation Guideline (Sipmann and Finlayson, 2000) applied to protect for 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 4602

LOE ID: | 15339
Pollutant: | Chlorpyrifos
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 4
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 Orcutt Creek to determine beneficial use support and results are as follows: 4 of 4 samples exceed the criterion for Chlorpyrifos.
Data Reference: | Final Data File used for assessment: SWAMP Sediment Chemistry Data from Region 3 Harbors, 2004
| 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 8/22/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 16156
Pollutant: | Chlorpyrifos
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for Orcutt Creek to determine beneficial use support and results are as follows: 2 of 3 samples exceed the criterion for Chlorpyrifos.
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
| Final Data File used for assessment: SWAMP Sediment Chemistry Data from Region 3 Harbors, 2004
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 Orcutt Creek was collected at 3 monitoring sites [ 312ORC001 - Orcutt Creek upstream of Santa Maria River at Sand Plant, 312GVT- Orcutt Creek at Brown Road, 312ORB-Orcutt Solomon Creek at Black Road]
Temporal Representation: | Data was collected on a single day 2/28/2007. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 1930
Pollutant: | Chlorpyrifos
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Wildlife Habitat
Number of Samples: | 6
Number of Exceedances: | 6
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Water was sampled at Orcutt Creek (ORC) and in the Santa Maria River (SMA) on four separate occasions (June 2002, September 2002, March 2003, and May 2003) (SWAMP, 2004). Water was toxic at both stations in September 2002 and May 2003 (4 exceedances of 4 measurements). Analysis of chlorpyrifos in water showed that on all occasions when water toxicity was observed, concentrations of chlorpyrifos exceeded the LC 50 for this pesticide for toxicity to Ceriodaphnia dubia. Toxicity Identification Evaluations of water samples from Orcutt Creek and the Santa Maria River showed toxicity to C. dubia was due to chlorpyrifos. At the station on Orcutt Creek, 2 of 2 samples were in exceedance of the aquatic life criteria.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | CDFG Hazardous Assessment Criteria for Aquatic Life: 4-day average = 0.014 ppb, 1-hour day average = 0.025 ppb.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Samples were collected at one station on Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | Samples were collected on 9/3/2002 and 5/28/2003.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):
LOE ID: | 1931
Pollutant: | Chlorpyrifos
LOE Subgroup: | Pollutant-Sediment
Matrix: | Sediment
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 1
Number of Exceedances: | 1
Data and Information Type: | Chemical monitoring of sediments
Data Used to Assess Water Quality: | Sediment was sampled at Orcutt Creek (ORC) and in the Santa Maria River (SMA) on two separate occasions (June 2002 and May 2003). Sediment was toxic at both stations in both samples (SWAMP, 2004). Analysis of chlorpyrifos in sediment porewater showed that on all occasions when water toxicity was observed, concentrations of chlorpyrifos exceeded the LC50 for this pesticide to the amphipod Hyalella azteca. Toxicity Identification Evaluations of sediment samples from Orcutt Creek and the Santa Maria River showed toxicity was due to a combination of chlorpyrifos and other pesticides, likely pyrethroid pesticides (refer to attached excel spreadsheet file). Sediment bulk-phase chemical analyses showed elevated concentrations of chlorpyrifos.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station on Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | Samples were collected in 5/28/2003.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures for the primary study were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):

DECISION ID | 4234
Pollutant: | Fecal Coliform
Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list)(2006)
Revision Status | Revised
Sources: | Agriculture | Grazing-Related Sources | Natural Sources | Onsite Wastewater Systems (Septic Tanks) | Urban Runoff/Storm Sewers
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 4.2 of the Listing Policy. Under section 4.2 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 #1928 is disregarded and replaced by LOE #11660 (which contains the same data) because the sample and exceedance count in LOE #1928 includes field duplicates that should not be included in the assessment. Therefore, LOE #1928 is not included in the current assessment. Two LOEs are assessed in this decision (LOE #11660 and LOE #11661). Twenty-five of the 45 samples exceed the Water Contact Recreation water quality objective and 5 of the 45 samples also exceed the Non-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. Twenty-five of the 45 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: | 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 4234

LOE ID: | 11660
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 45
Number of Exceedances: | 25
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Orcutt Creek to determine beneficial use support and results are as follows: 25 of 45 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 1/12/2000-4/6/2001. 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: | 11661
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 45
Number of Exceedances: | 5
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Orcutt Creek to determine beneficial use support and results are as follows: 5 of 45 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 1/12/2000-4/6/2001. 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: | 1928
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 50
Number of Exceedances: | 31
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Thirty-one of 50 samples exceed the water quality objective (CCAMP, 2004).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Basin Plan: Fecal coliform concentration, based on minimum of not less than five samples or any 30-day period, shall not exceed a log mean of 200/100 ml, nor shall more than ten percent of the total samples during any 30-day period exceed 400/100 ml.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Three sampling sites.
Temporal Representation: | Monthly sampling events.
Environmental Conditions: |
QAPP Information: | Central Coast Ambient Monitoring Program (CCAMP) QA/QC.
QAPP Information Reference(s):

DECISION ID | 4312
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 | Grazing-Related Sources | Other Urban Runoff | 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 4.1 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 lines of evidence are used to assess three Beneficial Uses. Note that LOE #1929 is disregarded and replaced by LOE #9736 (which contains the same data) however, data audits showed that three of the data points should not have been included in LOE #1929 because they are field duplicate samples. LOE #1929 is not included in the current assessment and therefore the data are not double counted. Three LOEs are used to assess the Municipal and Domestic Supply Beneficial Use. Forty-six of 61 of the samples exceed the Municipal and Domestic Supply water quality objective for Nitrate. In addition, 35 of 36 samples exceed the OEHHA public Health Goal for NO3+NO2 in Drinking Water (December 1997) as it applies to the Municipal and Domestic Supply beneficial use. Two LOEs are used to assess the Agricultural Supply Beneficial Use. Twenty-eight of the 61 samples exceed the Agricultural Supply water quality objective for Nitrate. Finally, two LOEs are used to assess the Cold Freshwater Habitat Beneficial Uses. Fifty-seven of the 61 samples exceeded the Numeric Nutrient Endpoint for Nitrate in the Central Coast Region. 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. Forty-six of 61 of the samples exceed the Municipal and Domestic Supply water quality objective for nitrate (NO3) and 35 of 36 samples exceed the OEHHA public Health Goal for NO3+NO2 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. Twenty-eight of the 61 samples also exceed the Agricultural Supply water quality objective for NO3 and this exceeds the allowable frequency calculated from the equation in Table 4.1 of the Listing Policy. 5. Fifty-seven of the 61 samples exceeded the Numeric Nutrient Endpoint for Nitrate in the Central Coast Region 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 4312

LOE ID: | 14353
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 13
Number of Exceedances: | 10
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 Orcutt Creek to determine beneficial use support and results are as follows: 10 of 13 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
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: | 1929
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 45
Number of Exceedances: | 31
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Thirty-one of 45 samples exceed the water quality objective (CCAMP, 2004).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Basin Plan: 45 mg/L (as Nitrate).
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Three sampling sites.
Temporal Representation: | Monthly sampling events. Samples taken from 1/12/00 to 2/28/01.
Environmental Conditions: |
QAPP Information: | Central Coast Ambient Monitoring Program (CCAMP) QA/QC.
QAPP Information Reference(s):
LOE ID: | 14239
Pollutant: | Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 36
Number of Exceedances: | 35
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 Orcutt Creek to determine beneficial use support and results are as follows: 35 of 36 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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: | 14257
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 13
Number of Exceedances: | 12
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 Orcutt Creek to determine beneficial use support and results are as follows: 12 of 13 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
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: | 9736
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 48
Number of Exceedances: | 34
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 Orcutt Creek to determine beneficial use support and results are as follows: 34 of 48 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 1/12/2000-4/6/2001. 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: | 9735
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 48
Number of Exceedances: | 18
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 Orcutt Creek to determine beneficial use support and results are as follows: 18 of 48 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 1/12/2000-4/6/2001. 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: | 27878
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 13
Number of Exceedances: | 12
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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
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: | 27879
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 48
Number of Exceedances: | 45
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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 1/12/2000-4/6/2001. 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 | 14793
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. Four of the 92 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. Four of the 92 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 14793

LOE ID: | 9722
Pollutant: | Chlorophyll-a
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 47
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 Orcutt Creek to determine beneficial use support and results are as follows: 2 of 47 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 1/12/2000-2/28/2001. 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: | 14426
Pollutant: | Chlorophyll-a
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 45
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 Orcutt Creek to determine beneficial use support and results are as follows: 2 of 45 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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 | 14801
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: Four of the 96 samples exceed the dissolved oxygen water quality objective for Warm Freshwater Habitat and 19 of 96 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. Four of the 96 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 14801

LOE ID: | 14427
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 46
Number of Exceedances: | 8
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 Orcutt Creek to determine beneficial use support and results are as follows: 8 of 46 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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: | 13554
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 42
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Santa Maria (SantaMaria) data for Orcutt Creek to determine beneficial use support and results are as follows: 0 of 42 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, Cold Water Habitat Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 2/3/2000-4/6/2001. 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: | 13555
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 42
Number of Exceedances: | 7
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 Orcutt Creek to determine beneficial use support and results are as follows: 7 of 42 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 2/3/2000-4/6/2001. 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: | 13572
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 2
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 Orcutt Creek to determine beneficial use support and results are as follows: 2 of 8 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, Cold Water Habitat Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/7/2000. 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: | 13573
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 4
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 Orcutt Creek to determine beneficial use support and results are as follows: 4 of 8 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/7/2000. 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: | 14243
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 46
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 Orcutt Creek to determine beneficial use support and results are as follows: 2 of 46 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, Cold Water Habitat Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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 | 14791
Pollutant: | Nitrogen, ammonia (Total Ammonia)
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the 94 samples exceed the Evaluation Guideline (EPA's Lifetime Health advisory level, 2006) applied to protect the Municipal & Domestic Supply beneficial use. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of the 94 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 14791

LOE ID: | 14240
Pollutant: | Ammonia as Nitrogen
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 46
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Orcutt Creek to determine beneficial use support and results are as follows: 0 of 46 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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: | 9719
Pollutant: | Ammonia as Nitrogen
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 48
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 Orcutt Creek to determine beneficial use support and results are as follows: 0 of 48 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 1/12/2000-4/6/2001. 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 | 14804
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 89 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 89 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 14804

LOE ID: | 13556
Pollutant: | Salinity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 35
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 Orcutt Creek to determine beneficial use support and results are as follows: 0 of 35 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 2/3/2000-4/6/2001. 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: | 12618
Pollutant: | Salinity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Orcutt Creek to determine beneficial use support and results are as follows: 0 of 8 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/7/2000. 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: | 14457
Pollutant: | Salinity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 46
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPSouth) data for Orcutt Creek to determine beneficial use support and results are as follows: 0 of 46 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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 | 14808
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. Four of 93 samples exceed the water quality objectives for Agricultural Supply and Cold Freshwater Habitat water quality objective while 5 of 93 samples exceed the numeric objectives 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. Four of 93 samples exceed the water quality objectives for Agricultural Supply and Cold Freshwater Habitat water quality objective while 5 of 93 samples exceed the numeric objectives 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 14808

LOE ID: | 11447
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Orcutt Creek to determine beneficial use support and results are as follows: 0 of 8 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/7/2000. 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: | 11718
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 39
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 Orcutt Creek to determine beneficial use support and results are as follows: 2 of 39 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 2/3/2000-4/6/2001. 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: | 11463
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Orcutt Creek to determine beneficial use support and results are as follows: 0 of 8 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/7/2000. 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: | 11443
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 39
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 Orcutt Creek to determine beneficial use support and results are as follows: 2 of 39 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 2/3/2000-4/6/2001. 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: | 11717
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 39
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 Orcutt Creek to determine beneficial use support and results are as follows: 2 of 39 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 2/3/2000-4/6/2001. 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: | 11716
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 39
Number of Exceedances: | 3
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 Orcutt Creek to determine beneficial use support and results are as follows: 3 of 39 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 2/3/2000-4/6/2001. 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: | 14440
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 46
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 Orcutt Creek to determine beneficial use support and results are as follows: 2 of 46 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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: | 14441
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 46
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 Orcutt Creek to determine beneficial use support and results are as follows: 1 of 46 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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: | 14442
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 46
Number of Exceedances: | 3
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 Orcutt Creek to determine beneficial use support and results are as follows: 3 of 46 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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: | 14443
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 46
Number of Exceedances: | 3
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 Orcutt Creek to determine beneficial use support and results are as follows: 3 of 46 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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: | 11715
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 39
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 Orcutt Creek to determine beneficial use support and results are as follows: 2 of 39 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 2/3/2000-4/6/2001. 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: | 14456
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 46
Number of Exceedances: | 3
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 Orcutt Creek to determine beneficial use support and results are as follows: 3 of 46 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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: | 11446
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Orcutt Creek to determine beneficial use support and results are as follows: 0 of 8 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/7/2000. 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: | 11445
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Orcutt Creek to determine beneficial use support and results are as follows: 0 of 8 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/7/2000. 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: | 11462
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP Diurnal Dissolved Oxygen Sampling (DO) data for Orcutt Creek to determine beneficial use support and results are as follows: 0 of 8 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/7/2000. 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 | 14792
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 | Other Urban Runoff
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. Forty-six of 48 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 14792

LOE ID: | 9721
Pollutant: | Chloride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 48
Number of Exceedances: | 46
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 Orcutt Creek to determine beneficial use support and results are as follows: 46 of 48 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 1/12/2000-4/6/2001. 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 | 14794
Pollutant: | Diazinon
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | 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 3.1 of the Listing Policy. Two lines of evidence are available in the administrative record to assess this pollutant. Based on section 3.1 the site exceeded numeric objectives for toxic pollutants. Using 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 3.1. 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. Four of 7 samples exceeded the Evaluation Guideline (Sipmann and Finlayson, 2000) applied to protect for aquatic life beneficial uses 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 14794

LOE ID: | 16804
Pollutant: | Diazinon
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold 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_SWAMP Monitoring (04SW3001) data for Orcutt Creek to determine beneficial use support and results are as follows: 3 of 3 samples exceed the criterion for Diazinon.
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
| Final Data File used for assessment: SWAMP Sediment Chemistry Data from Region 3 Harbors, 2004
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 Orcutt Creek was collected at 3 monitoring sites [ 312ORC001 - Orcutt Creek upstream of Santa Maria River at Sand Plant, 312GVT- Orcutt Creek at Brown Road, 312ORB-Orcutt Solomon Creek at Black Road]
Temporal Representation: | Data was collected on a single day 2/28/2007. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 15340
Pollutant: | Diazinon
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 4
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 Orcutt Creek to determine beneficial use support and results are as follows: 1 of 4 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 8/22/2006-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 14802
Pollutant: | Electrical Conductivity
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture | Other Urban Runoff | 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. Two lines of evidence are available in the administrative record to assess this pollutant. Based on section 3.2 the site exceeded numeric objectives for conventional pollutants. According to the binomial distribution, waters shall be placed on the section 303(d) list if the number of measured exceedances supports rejection of the null hypothesis as presented in Table 3.2. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Thirteen of 44 samples exceeded the water quality objective 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 14802

LOE ID: | 11662
Pollutant: | Electrical Conductivity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 36
Number of Exceedances: | 11
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 Orcutt Creek to determine beneficial use support and results are as follows: 11 of 36 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 2/3/2000-4/6/2001. 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: | 11444
Pollutant: | Electrical Conductivity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 8
Number of Exceedances: | 2
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 Orcutt Creek to determine beneficial use support and results are as follows: 2 of 8 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/7/2000. 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 | 14803
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 | Other Urban Runoff
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. All four 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. All four 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 14803

LOE ID: | 23991
Pollutant: | Invertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Sediment
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 2
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPsouth) data for Orcutt Creek to determine beneficial use support and results are as follows: 2 of 2 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 Orcutt Creek was collected at 2 monitoring sites [ 312OR1 - Orcutt Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 4/19/2005-4/20/2005. 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: | 23946
Pollutant: | Invertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Sediment
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 2
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPsouth) data for Orcutt Creek to determine beneficial use support and results are as follows: 2 of 2 samples exceed the criterion for Toxicity, Hyalella azteca Survival (%) 10 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
Data Reference: | Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
| Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
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 Orcutt Creek was collected at 2 monitoring sites [ 312OR1 - Orcutt Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 5/15/2006-5/16/2006. 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 | 14805
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: | 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. Forty-six of 48 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 14805

LOE ID: | 9737
Pollutant: | Sodium
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 48
Number of Exceedances: | 46
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 Orcutt Creek to determine beneficial use support and results are as follows: 46 of 48 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 1/12/2000-4/6/2001. 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 | 14806
Pollutant: | Temperature, water
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture | Grazing-Related Sources | Removal of Riparian Vegetation
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. Three lines of evidence are available in the administrative record to assess this pollutant. Based on section 3.2 the site exceeded numeric objectives for conventional pollutants. According to the binomial distribution, waters shall be placed on the section 303(d) list if the number of measured exceedances supports rejection of the null hypothesis as presented in Table 3.2. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This Evaluation Guideline is relevant for Orcutt Creek as it is a tributary to Santa Maria River and is the primary source of water to the lowest reaches of the River in the dry season. A recent publication (Steelhead/Rainbow Trout (Oncorhynchus mykiss) Resources South of the Golden Gate, California (Becker, G.S and I.J Reining, October 2008) identifies Santa Maria River as having "Definite run or population". Therefore, discharge of warm water from Orcutt Creek is specifically prohibited by the General Objectives in the Central Coast Water Quality Control Plan which states that natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses. 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-eight of 93 samples exceeded the Evaluation Guideline (Moyle 1976) applied to protect the Cold Freshwater Habitat beneficial use 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 14806

LOE ID: | 14459
Pollutant: | Temperature, water
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 46
Number of Exceedances: | 13
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 Orcutt Creek to determine beneficial use support and results are as follows: 13 of 46 samples exceed the criterion for Water Temperature.
Data Reference: | Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
| Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
Water Quality Objective/Criterion: | Natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses (General Objective in Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).
Guideline Reference: | Inland Fishes of California
Spatial Representation: | Data for this line of evidence for Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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: | 13570
Pollutant: | Temperature, water
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 39
Number of Exceedances: | 15
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 Orcutt Creek to determine beneficial use support and results are as follows: 15 of 39 samples exceed the criterion for Water Temperature.
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: | Natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses (General Objective in Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).
Guideline Reference: | Inland Fishes of California
Spatial Representation: | Data for this line of evidence for Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 2/3/2000-4/6/2001. 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: | 13588
Pollutant: | Temperature, water
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 8
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 Orcutt Creek to determine beneficial use support and results are as follows: 0 of 8 samples exceed the criterion for Water Temperature.
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: | Natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses (General Objective in Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).
Guideline Reference: | Inland Fishes of California
Spatial Representation: | Data for this line of evidence for Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/7/2000. 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 | 14807
Pollutant: | Turbidity
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture | Grazing-Related Sources | Removal of Riparian Vegetation
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. Three lines of evidence are available in the administrative record to assess this pollutant. Based on section 3.2 the site exceeded numeric objectives for conventional pollutants. According to the binomial distribution, waters shall be placed on the section 303(d) list if the number of measured exceedances supports rejection of the null hypothesis as presented in Table 3.2. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This Evaluation Guideline is relevant for Orcutt Creek as it is a tributary to Santa Maria River and is the primary source of water to the lowest reaches of the River in the dry season. A recent publication (Steelhead/Rainbow Trout (Oncorhynchus mykiss) Resources South of the Golden Gate, California (Becker, G.S and I.J Reining, October 2008) identifies Santa Maria River as having "Definite run or population". Therefore, discharge of turbid water from Orcutt Creek is specifically prohibited by the General Objectives in the Central Coast Water Quality Control Plan which states that waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Fifty-eight of 76 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. 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 14807

LOE ID: | 14458
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 46
Number of Exceedances: | 35
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 Orcutt Creek to determine beneficial use support and results are as follows: 35 of 46 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 Orcutt Creek was collected at 2 monitoring sites [ 312ORI-Orcutt Solomon Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 1/27/2005-12/14/2006. 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: | 12619
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 6
Number of Exceedances: | 5
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 Orcutt Creek to determine beneficial use support and results are as follows: 5 of 6 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 6/27/2000-9/7/2000. 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: | 13571
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 24
Number of Exceedances: | 18
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 Orcutt Creek to determine beneficial use support and results are as follows: 18 of 24 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 4/12/2000-4/6/2001. 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 | 15446
Pollutant: | Unknown Toxicity
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture | Grazing-Related Sources | Other Urban Runoff | Removal of Riparian Vegetation
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. Nine lines of evidence are available in the administrative record to assess this pollutant in water samples. Sixteen 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. None of the 14 samples (tested for toxicity to vertebrate test organisms), exceed the narrative General Objective for toxicity. However, 3 of the 14 samples (tested for toxicity to plants), exceed the narrative General Objective for toxicity and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. In addition, 13 of the 18 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. 3 of the 14 samples (tested for toxicity to plants), exceed the narrative General Objective for toxicity and 13 of the 18 samples (tested for toxicity to invertebrate test organisms), exceed the narrative General Objective for toxicity. Both of these 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 15446

LOE ID: | 24568
Pollutant: | Vertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for Orcutt Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Toxicity, Pimephales promelas Survival (%) 7 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for Orcutt Creek was collected at 3 monitoring sites [ 312ORC001 - Orcutt Creek upstream of Santa Maria River at Sand Plant, 312GVT- Orcutt Creek at Brown Road, 312ORB-Orcutt Solomon Creek at Black Road]
Temporal Representation: | Data was collected on a single day 2/28/2007. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 24579
Pollutant: | Plant Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 3
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for Orcutt Creek to determine beneficial use support and results are as follows: 3 of 3 samples exceed the criterion for Toxicity, Selenastrum capricornutum Growth (Cell Density) 4 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Significant reduction in cell count of test organism relative to the control (alpha < 0.05) and cell count <80% of control.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for Orcutt Creek was collected at 3 monitoring sites [ 312ORC001 - Orcutt Creek upstream of Santa Maria River at Sand Plant, 312GVT- Orcutt Creek at Brown Road, 312ORB-Orcutt Solomon Creek at Black Road].
Temporal Representation: | Data was collected on a single day 2/28/2007. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 24567
Pollutant: | Vertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 10
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 Orcutt Creek to determine beneficial use support and results are as follows: 0 of 10 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 Orcutt Creek was collected at 2 monitoring sites [ 312OR1 - Orcutt Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 2/21/2005-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 23929
Pollutant: | Vertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPsouth) data for Orcutt Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Toxicity, Cyprinodon variegatus 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 Orcutt Creek was collected at 1 monitoring site [ 312OR1 - Orcutt Creek at Highway 1]
Temporal Representation: | Data was collected on a single day 8/22/2006. 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: | 23920
Pollutant: | Invertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 12
Number of Exceedances: | 7
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 Orcutt Creek to determine beneficial use support and results are as follows: 7 of 12 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 Orcutt Creek was collected at 2 monitoring sites [ 312OR1 - Orcutt Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 3/22/2005-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 23945
Pollutant: | Invertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 3
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 Orcutt Creek to determine beneficial use support and results are as follows: 3 of 3 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 Orcutt Creek was collected at 2 monitoring sites [ 312OR1 - Orcutt Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 9/27/2005-8/22/2006. 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: | 24580
Pollutant: | Plant Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCWQP Southern Area Ag-Waiver Monitoring (R3_CMPsouth) data for Orcutt Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Toxicity, Thalassiosira 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 Orcutt Creek was collected at 1 monitoring site [ 312OR1 - Orcutt Creek at Highway 1]
Temporal Representation: | Data was collected on a single day 8/22/2006. 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: | 24578
Pollutant: | Plant Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 10
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 Orcutt Creek to determine beneficial use support and results are as follows: 0 of 10 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 Orcutt Creek was collected at 2 monitoring sites [ 312OR1 - Orcutt Creek at Highway 1, 312ORC-Orcutt Solomon Creek u/s Santa Maria River]
Temporal Representation: | Data was collected over the time period 2/21/2005-9/27/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
LOE ID: | 23927
Pollutant: | Invertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 3
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for Orcutt Creek to determine beneficial use support and results are as follows: 3 of 3 samples exceed the criterion for Toxicity, Ceriodaphnia dubia Survival (%) 7 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
Data Reference: | Final Data File used for assessment: SWAMP Toxicity Data 2001-06
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: | Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Spatial Representation: | Data for this line of evidence for Orcutt Creek was collected at 3 monitoring sites [ 312ORC001 - Orcutt Creek upstream of Santa Maria River at Sand Plant, 312GVT- Orcutt Creek at Brown Road, 312ORB-Orcutt Solomon Creek at Black Road]
Temporal Representation: | Data was collected on a single day 2/28/2007. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):

DECISION ID | 4606
Pollutant: | Aluminum
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
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. A single sample exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is insufficient 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. Only one sample exceeded the Secondary MCL. More data is needed to determine if the water quality objective is exceeded. 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: | No new data were assessed for 2008. The decision has not changed.
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 placed on the section 303(d) list because it cannot be determined if applicable water quality standards are exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4606

LOE ID: | 1936
Pollutant: | Aluminum
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 1
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | One sample was collected on Orcutt Creek in September 2002. This sample was in exceedance of the secondary MCL (SWAMP, 2004).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. Title 22 MCL = 1 mg/L; Secondary MCL = 0.2 mg/L.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | One sample was collected on 9/3/2002.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):

DECISION ID | 4594
Pollutant: | Dacthal
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for listing under section 3.6, and 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status and under 3.6 a segment may be listed for toxicity alone. Two lines of evidence are available in the administrative record to assess this pollutant. Based on section 3.6 sediment toxicity was recorded but it cannot be determined if the pollutant is likely to cause or contribute to the toxic effect. Dacthal was also detected in the watercolumn but there in no numeric criteria or guideline that meets the requirement of the Listing Policy. Based on the readily available data and information, the weight of evidence indicates that there is not 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. A sediment based numeric criteria in sediment or in the water column for dacthal is not available that complies with the requirements of section 6.1.3 of the Policy. 2. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 3. The data used satisfies the data quantity requirements of section 6.1.5 of the 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: | No new data were assessed for 2008. The decision has not changed.
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 placed on the section 303(d) list because it cannot be determined if applicable water quality standards are exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4594

LOE ID: | 1939
Pollutant: | Dacthal
LOE Subgroup: | Pollutant-Sediment
Matrix: | Sediment
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Chemical monitoring of sediments
Data Used to Assess Water Quality: | Sediment was sampled at Orcutt Creek (ORC) and in the Santa Maria River (SMA) in 2002 and 2003. Sediment was toxic at both stations in both samples (Anderson, B. 2004). Sediment bulk-phase chemical analyses showed elevated concentrations of dacthal, however no numeric criteria are available.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Orcutt Creek (a tributary to the Santa Maria River) at two sampling stations.
Temporal Representation: | Samples were collected on 5/28/2003.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures for the primary study were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):
LOE ID: | 1940
Pollutant: | Dacthal
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 2
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Water was sampled at Orcutt Creek (ORC) and in the Santa Maria River (SMA) on two separate occasions (September 2002 and May 2003). Water was toxic at both stations in September 2002 and May 2003 (Anderson, B. 2004). Dacthal was detected in both samples on the Santa Maria River, however no numeric criteria are available.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Orcutt Creek (a tributary to the Santa Maria River) at two sampling stations.
Temporal Representation: | Samples were collected on 9/3/2002 and 5/28/2003.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):

DECISION ID | 4607
Pollutant: | Iron
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
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. A single sample exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is insufficient 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. Only one sample exceeded the Title 22 Secondary MCL. More data is needed to determine if the water quality objective is exceeded. 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: | No new data were assessed for 2008. The decision has not changed.
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 placed on the section 303(d) list because it cannot be determined if applicable water quality standards are exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4607

LOE ID: | 1937
Pollutant: | Iron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 1
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | One sample was collected on Orcutt Creek in September 2002 (SWAMP, 2004). This sample was in exceedance of the secondary MCL.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. Title 22 Secondary MCL = 0.3 mg/L.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | One sample was collected on 9/3/2002.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):

DECISION ID | 4593
Pollutant: | Manganese
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
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. A single sample exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is insufficient 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. Only one sample exceeded the Title 22 Secondary MCL. More data is needed to determine if the water quality objective is exceeded. 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: | No new data were assessed for 2008. The decision has not changed.
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 placed on the section 303(d) list because it cannot be determined if applicable water quality standards are exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4593

LOE ID: | 1938
Pollutant: | Manganese
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 1
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | One sample was collected on Orcutt Creek in September 2002 (SWAMP, 2004). This sample was in exceedance of the secondary MCL.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. Title 22 Secondary MCL = 0.05 mg/L.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | One sample was collected on 9/3/2002.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):

DECISION ID | 6560
Pollutant: | Boron
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Sources: | Agriculture | Other Urban Runoff
Expected TMDL Completion Date: | 2013
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | 303(d) listing decisions made prior to 2006 were not held in an assessment database. The Regional Boards will update this decision when new data and information become available and are assessed.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | N/A
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 6560

LOE ID: | 9751
Pollutant: | Boron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Agricultural Supply
Number of Samples: | 12
Number of Exceedances: | 4
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 Orcutt Creek to determine beneficial use support and results are as follows: 4 of 12 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 4/12/2000-6/26/2000. 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):
LOE ID: | 3976
Pollutant: | Boron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Not Recorded
Beneficial Use: | Agricultural Supply
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: | 9720
Pollutant: | Boron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Agricultural Supply
Number of Samples: | 36
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 Orcutt Creek to determine beneficial use support and results are as follows: 5 of 36 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 Orcutt Creek was collected at 3 monitoring sites [ 312ORB-Orcutt Solomon Creek at Black Road, 312ORC-Orcutt Solomon Creek u/s Santa Maria River, 312ORI-Orcutt Solomon Creek at Highway 1]
Temporal Representation: | Data was collected over the time period 1/12/2000-4/6/2001. 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 | 4595
Pollutant: | DDT (Dichlorodiphenyltrichloroethane)
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Sources: | Agriculture | Other Urban Runoff | 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 section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Six lines of evidence are available in the administrative record to assess this pollutant. Three lines of evidence pertain to the pollutant in water and three pertain to the pollutant in sediment. A sufficient number of samples exceed the Human Health criteria for the different types of degradation products of DDT. 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 water quality guideline used complies with the requirements of section 6.1.3 of the Policy. 2.The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 3. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 4. Samples were taken in 2002 and 2003. Two of 2 samples (2002 and 2003) exceeded the total DDT, 2 of 2 samples exceeded 4,4' DDD, and 2 of 2 samples exceeded the 4,4' DDE Human Health (water consumption) criteria and these exceed the allowable frequency listed in Table 3.1 of the Listing Policy. Even though sediment toxicity was found in 2003 the measurements of these chemicals in the sediment did not exceed the sediment guideline. 5.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: | No new data were assessed for 2008. The decision has not changed.
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 4595

LOE ID: | 1941
Pollutant: | DDD (Dichlorodiphenyldichloroethane)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 2
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Samples were collected on Orcutt Creek on two occasions: in 2002 and 2003 (SWAMP, 2004). Both measurements for 4,4'-DDD exceeded the human health criteria for water consumption (0.00083 ppb).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life. CTR criteria for: Human Health (water consumption) = 0.00083 ppb for 4,4'-DDD.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station on Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | Samples were collected on 9/3/2002 and 5/28/2003.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):
LOE ID: | 1932
Pollutant: | DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 2
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Samples were collected on Orcutt Creek on two occasions: in 2002 and 2003 (SWAMP, 2004). Both measurements for total DDTs and 4,4'-DDT were below freshwater acute criteria, however both measurements exceeded human health criteria for water consumption for both 4,4'-DDT and DDTs (total).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life. CTR criteria for: Freshwater acute = 1.1 ppb for 4,4'-DDT and DDTs (total). Human Health (water consumption) = 0.00059 ppb for 4,4'-DDT. Human Health (water consumption) = 0.0059 ppb for DDTs (total).
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station on Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | Samples were collected on 9/3/2002 and 5/28/2003.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):
LOE ID: | 1942
Pollutant: | DDD (Dichlorodiphenyldichloroethane)
LOE Subgroup: | Pollutant-Sediment
Matrix: | Sediment
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | Chemical monitoring of sediments
Data Used to Assess Water Quality: | Sediment was sampled at Orcutt Creek (ORC) and in the Santa Maria River (SMA) in 2002 and 2003 (SWAMP, 2004). In the Orcutt Creek sample, the sediment criterion for DDD (sum) was not exceeded on either occasion.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life. Freshwater Sediment Criteria (Policy): DDD(sum) = 28.0 ppb.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station on Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | Samples were collected on 6/28/2002 and 5/28/2003.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures for the primary study were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):
LOE ID: | 1943
Pollutant: | DDE (Dichlorodiphenyldichloroethylene)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 2
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Samples were collected on Orcutt Creek on two occasions: in 2002 and 2003 (SWAMP, 2004). Both measurements for 4,4'-DDE exceeded the human health criteria for water consumption (0.00059 ppb).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life. CTR criteria for: Human Health (water consumption) = 0.00059 ppb for 4,4'-DDE.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station on Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | Samples were collected on 9/3/2002 and 5/28/2003.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):
LOE ID: | 1944
Pollutant: | DDE (Dichlorodiphenyldichloroethylene)
LOE Subgroup: | Pollutant-Sediment
Matrix: | Sediment
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 2
Number of Exceedances: | 1
Data and Information Type: | Chemical monitoring of sediments
Data Used to Assess Water Quality: | Sediment was sampled at Orcutt Creek (ORC) and in the Santa Maria River (SMA) in 2002 and 2003 (SWAMP, 2004). In the Orcutt Creek sample, the sediment criterion for DDE (sum) was exceeded in 2003, but not in 2002.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life. Freshwater Sediment Criteria: DDE(sum) = 31.3 ppb
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station on Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | Samples were collected on 6/28/2002 and 5/28/2003.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures for the primary study were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):
LOE ID: | 1933
Pollutant: | DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup: | Pollutant-Sediment
Matrix: | Sediment
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 2
Number of Exceedances: | 1
Data and Information Type: | Chemical monitoring of sediments
Data Used to Assess Water Quality: | Sediment was sampled at Orcutt Creek (ORC) and in the Santa Maria River (SMA) in 2002 and 2003 (SWAMP, 2004). In the Orcutt Creek sample, the sediment criterion for DDT (sum) was exceeded (62.9 ppb) in the 2003 sample, but not in 2002 sample. The DDTs (total) criterion (572 ppb) was not exceeded on either occasion.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life. Freshwater Sediment Criteria (Policy): DDT(sum) = 62.9 ppb DDTs(total) = 572
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station on Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | Samples were collected on 6/28/2002 and 5/28/2003.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures for the primary study were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):

DECISION ID | 4605
Pollutant: | Dieldrin
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Sources: | Agriculture | Other Urban Runoff | 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 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. A sufficient number of samples exceed the CTR Human Health criteria. 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. Two of 2 samples exceeded the CTR Human Heath criteria and this exceeds the allowable frequency listed in Table 3.1. Sediment samples were taken but dieldrin results were below the detection limits. 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: | No new data were assessed for 2008. The decision has not changed.
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 4605

LOE ID: | 1935
Pollutant: | Dieldrin
LOE Subgroup: | Pollutant-Sediment
Matrix: | Sediment
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Chemical monitoring of sediments
Data Used to Assess Water Quality: | Sediment was sampled at Orcutt Creek (ORC) in May 2003 and the dieldrin level was below the detection limit (SWAMP, 2004).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life. Freshwater Sediment criterion: max Dieldrin = 6.18 ppm.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | The sample was collected at one station on Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | One sample was collected on 5/28/2003.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures for the primary study were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):
LOE ID: | 1934
Pollutant: | Dieldrin
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 2
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Samples were collected on Orcutt Creek in September 2002 and May 2003 (SWAMP, 2004). Two of 2 samples were in exceedance of the CTR Human Health criterion for water consumption.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | General WQOs: 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 the 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. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life. CTR Human Health Criterion for consumption of Water & Organisms = 0.00014 ppb.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station on Orcutt Creek (a tributary to the Santa Maria River).
Temporal Representation: | Samples were collected on 9/3/2002 and 5/28/2003.
Environmental Conditions: |
QAPP Information: | Quality assurance and quality control procedures were identical to those used in the Surface Water Ambient Monitoring Program (SWAMP). The toxicity and chemistry laboratories participating in this study are the same labs responsible for the SWAMP QAPP, and are the labs participating in the SWAMP program.
QAPP Information Reference(s):