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

Supporting Information

Regional Board 3 - Central Coast Region

Water Body Name: Los Osos Creek Estuary
Water Body ID: CAR3102300020150205055500
Water Body Type: River & Stream
 
DECISION ID
87382
Region 3     
Los Osos Creek Estuary
 
Pollutant: Oxygen, Dissolved
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)(2016)
Revision Status Original
Sources: Source Unknown
Expected TMDL Completion Date: 2027
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Note: This decision was formerly associated with Los Osos Creek but in the 2014 assessment cycle was transferred to the newly mapped ¿Los Osos Creek Estuary¿, where the monitoring stations associated with the LOEs in this decision are located. The 'Listing Year' associated with every LOE is 2014, regardless of the year the LOE was created. This is because the old LOEs (pre 2014) were moved to this newly mapped water segment in 2014 and this process changed the date associated with the LOE in the assessment data base.

This pollutant is being considered for removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Seven lines of evidence are available in the administrative record to assess this pollutant. Forty-seven of the 98 samples exceeded the water quality objective for dissolved oxygen in Cold Freshwater Habitats and 28 of the 98 samples exceeded the water quality objective for dissolved oxygen in Warm Freshwater Habitats. The Basin Plan general water quality objective for oxygen saturation states that the median value shall not fall below 85% saturation. Furthermore, the oxygen saturation objective is only applied ¿for waters not mentioned by a specific beneficial use¿¿ and this water body is designated for both Cold and Warm Freshwater Habitats. Therefore, the use support rating for oxygen saturation is set at Insufficient Information.

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

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-seven of the 98 samples exceeded the water quality objective for dissolved oxygen in Cold Freshwater Habitats and 28 of the 98 samples exceeded the water quality objective for dissolved oxygen in Warm Freshwater Habitats. These exceed the allowable frequency listed in Table 4.2 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
 
State Board Staff Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 87382, Oxygen, Dissolved
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80774
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 95
Number of Exceedances: 28
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 28 of 95 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 87382, Oxygen, Dissolved
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80773
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 87382, Oxygen, Dissolved
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80783
 
Pollutant: Dissolved oxygen saturation
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 91
Number of Exceedances: 64
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 64 of 91 samples exceed the criterion for Oxygen, Saturation.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Median values should not fall below 85% saturation as a result of controllable water quality conditions (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 87382, Oxygen, Dissolved
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80778
 
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: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan, Central Coast Basin, Cold Water Habitat Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 87382, Oxygen, Dissolved
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80777
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 95
Number of Exceedances: 47
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 47 of 95 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 87382, Oxygen, Dissolved
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80779
 
Pollutant: Low Dissolved Oxygen
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference pre-2006 303(d)
 
SWAMP Data: Non-SWAMP
 
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):
 
Line of Evidence (LOE) for Decision ID 87382, Oxygen, Dissolved
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80781
 
Pollutant: Dissolved oxygen saturation
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 91
Number of Exceedances: 64
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 64 of 91 samples exceed the criterion for Oxygen, Saturation.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Median values should not fall below 85% saturation as a result of controllable water quality conditions (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
 
DECISION ID
87330
Region 3     
Los Osos Creek Estuary
 
Pollutant: Fecal Coliform
Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)(2016)
Revision Status Original
Sources: Domestic Pet Waste | Grazing-Related Sources | Natural Sources | Onsite Wastewater Systems (Septic Tanks) | Transient encampments | Urban Runoff/Storm Sewers
TMDL Name: Morro Bay Pathogens
TMDL Project Code: 22
Date TMDL Approved by USEPA: 01/20/2004
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Note: This decision was formerly associated with Los Osos Creek but in the 2014 assessment cycle was transferred to the newly mapped ¿Los Osos Creek Estuary¿, where the monitoring stations associated with the LOEs in this decision are located. The 'Listing Year' associated with every LOE is 2014, regardless of the year the LOE was created. This is because the old LOEs (pre 2014) were moved to this newly mapped water segment in 2014 and this process changed the date associated with the LOE in the assessment data base.

This pollutant is being considered for delisting under section 2.2 of the Listing Policy. Under this section of the Policy, a minimum of one line of evidence is needed to assess listing status.

The Morro Bay Pathogens TMDL was approved by RWQCB on May 16, 2003 and subsequently approved by USEPA on January 20, 2004.

Three lines of evidence are available in the administrative record to assess this pollutant. LOE # 1907 is a placeholder for this listing which was made prior to 2006 when the assessment data base was initiated. The original listing was based on 10 years of data from the National monitoring Program in the Morro Bay Watershed. Two additional LOE summarize a single sample and the single sample does not exceed the water quality objectives for Water Contact Recreation or Non-Contact Recreation.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification in favor of delisting this water segment-pollutant combination from the Water Quality Limited Segments Being Addressed portion of the section 303(d) list.
 
Regional Board Decision Recommendation: This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current cycle. The decision has not changed.
 
State Board Staff Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 87330, Fecal Coliform
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80806
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference 2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion:
Objective/Criterion Reference:
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation:
Temporal Representation:
Environmental Conditions:
QAPP Information: QA Info Missing
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 87330, Fecal Coliform
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80808
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Coliform, Fecal.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Central Coast Basin objective for water contact recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: 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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected on a single day 5/17/2003. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 87330, Fecal Coliform
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80809
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Coliform, Fecal.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: 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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected on a single day 5/17/2003. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
 
DECISION ID
86581
Region 3     
Los Osos Creek Estuary
 
Pollutant: Nitrate
Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)(2016)
Revision Status Original
Sources: Agriculture | Grazing-Related Sources
TMDL Name: Los Osos Creek Nutrients
TMDL Project Code: 597
Date TMDL Approved by USEPA: 03/01/2005
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Note: This decision was formerly associated with Los Osos Creek but in the 2014 assessment cycle was transferred to the newly mapped ¿Los Osos Creek Estuary¿, where the monitoring stations associated with the LOEs in this decision are located. The 'Listing Year' associated with every LOE is 2014, regardless of the year the LOE was created. This is because the old LOEs (pre 2014) were moved to this newly mapped water segment in 2014 and this process changed the date associated with the LOE in the assessment data base.

The original decision to add Los Osos Creek (specifically based on nitrate data from this station) to the 303(d) List for 'Nutrients' was made prior to the creation of this assessment data base. There are no data or documents associated with this decision. The pollutant name has been changed from 'Nutrients' to 'Nitrate'.

This pollutant is being considered for removal on the CWA section 303(d) List under sections 2.2 and 4.1 of the Listing Policy. Under 4.1 of the Policy, a minimum of one line of evidence is needed to assess listing status.

Eight lines of evidence are available in the administrative record to assess this pollutant. One of the 96 samples exceeds the water quality objective for municipal and domestic supply uses (i.e. drinking water). Thirty-four of the 93 samples exceed the Central Coast Region¿s evaluation guideline for maximum nitrate concentration (R3 NNE Technical Report, 2010) and the protection of aquatic life uses from bio-stimulatory or eutrophic effects (i.e. enhanced algal and aquatic plant growth and unhealthy dissolved oxygen fluctuations). However, to determine if the aquatic life uses are negatively impacted by nitrate concentrations, the Central Coast Region requires supporting evidence indicating high risk for, or occurrence of, eutrophication. Los Oso Creek Estuary is also on the CWQ section 303(d) List due to low dissolved oxygen and therefore there is evidence of eutrophic conditions in this water segment.

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

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3.Thirty-four of the 93 samples exceed the Central Coast Region¿s evaluation guideline for protection of aquatic life uses from bio-stimulatory or eutrophic effects and these exceed the allowable frequency listed in Table 4.1 of the Listing Policy. Furthermore, Los Oso Creek Estuary is also on the CWQ section 303(d) List due to low dissolved oxygen and therefore there is evidence of eutrophic conditions in this water segment.
4. The Los Osos Creek Nutrients TMDL was approved by the RWQCB in December 2004 and subsequently approved by USEPA in March of 2005.
5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because the sample size is insufficient to determine with the power and confidence of the Listing Policy if water quality standards are being met.
 
State Board Staff Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 86581, Nitrate
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80772
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Nitrate as N.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 86581, Nitrate
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80751
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 93
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 1 of 93 samples exceed the criterion for Nitrate as N.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for nitrate (NO3 as N) incorporated by reference in the Basin Plan is 10.0 mg/L (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: Nitrate data was collected using a screening level test kit. Quality control is consistent with the QAPP.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 86581, Nitrate
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80750
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 93
Number of Exceedances: 34
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 34 of 93 samples exceed the criterion for Nitrate as N.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect beneficial uses (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Technical Approach to Develop Nutrient Numeric Endpoints for California. U.S. EPA Region IX. State Water Resources Control Board. 68-C-02-108-To-111
  Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: Nitrate data was collected using a screening level test kit. Quality control is consistent with the QAPP.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 86581, Nitrate
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80774
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 95
Number of Exceedances: 28
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 28 of 95 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 86581, Nitrate
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80777
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 95
Number of Exceedances: 47
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 47 of 95 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 86581, Nitrate
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80765
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference 2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion:
Objective/Criterion Reference:
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation:
Temporal Representation:
Environmental Conditions:
QAPP Information: QA Info Missing
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 86581, Nitrate
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80752
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 93
Number of Exceedances: 34
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 34 of 93 samples exceed the criterion for Nitrate as N.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect beneficial uses (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Technical Approach to Develop Nutrient Numeric Endpoints for California. U.S. EPA Region IX. State Water Resources Control Board. 68-C-02-108-To-111
  Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: Nitrate data was collected using a screening level test kit. Quality control is consistent with the QAPP.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 86581, Nitrate
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80768
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Nitrate as N.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Central Coast Basin Objective for municipal and domestic supply uses of inland surface waters (Section II.A.2) states the following: waters shall not contain concentrations of chemical constituents in excess of the limits specified in California Code of Regulations, Title 22, Article 4, Chapter 15, Section 64435, Tables 2 and 3 as listed in Table 3-2. The maximum contaminant level listed in Table 3-2 (inorganic and fluoride concentrations not to be exceeded in domestic or municipal supply) for nitrate is 10.0 mg/L (NO3 as N).
Objective/Criterion Reference: Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
  Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
 
DECISION ID
87327
Region 3     
Los Osos Creek Estuary
 
Pollutant: Enterococcus
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Note: This decision was formerly associated with Los Osos Creek but in the 2014 assessment cycle was transferred to the newly mapped ¿Los Osos Creek Estuary¿, where the monitoring stations associated with the LOEs in this decision are located. The 'Listing Year' associated with every LOE is 2014, regardless of the year the LOE was created. This is because the old LOEs (pre 2014) were moved to this newly mapped water segment in 2014 and this process changed the date associated with the LOE in the assessment data base.

This pollutant is being considered for placement on the CWA section 303(d) List under section 3.3 of the Listing Policy. Under section 3.3 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. Eight of the 51 samples exceed the evaluation guideline (USEPA Ambient Water Quality Criteria for Bacteria -1986) set to protect for Water Contact Recreation (i.e. swimming, wading etc.).

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

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Eight of the 51 samples exceed the evaluation guideline and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Staff Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 87327, Enterococcus
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80811
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 51
Number of Exceedances: 8
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 8 of 51 samples exceed the criterion for Enterococci.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: USEPA Ambient Water Quality Criteria for Bacteria -1986.
Objective/Criterion Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Evaluation Guideline: Single sample maximum allowable density for Enterococci in marine waters is 104 MPN/100mL (as stated in Table 4, page 15 of the USEPA Ambient Water Quality Criteria for Bacteria -1986).
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 3/9/2005 1:43:00 PM-2/11/2010 11:40:00 AM.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
 
DECISION ID
84541
Region 3     
Los Osos Creek Estuary
 
Pollutant: Escherichia coli (E. coli)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Note: This decision was formerly associated with Los Osos Creek but in the 2014 assessment cycle was transferred to the newly mapped ¿Los Osos Creek Estuary¿, where the monitoring stations associated with the LOEs in this decision are located. The 'Listing Year' associated with every LOE is 2014, regardless of the year the LOE was created. This is because the old LOEs (pre 2014) were moved to this newly mapped water segment in 2014 and this process changed the date associated with the LOE in the assessment data base.

This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. One of the 2 samples exceed the Evaluation Guideline (USEPA Ambient Water Quality Criteria for Bacteria, 1986) as it applies to the Water Contact Recreation beneficial use. Neither sample exceeds the water quality objective for Non-Contact Recreation. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 26 samples is needed to determine if a beneficial use is supported and a minimum of five exceedances is needed to determine if beneficial uses are not supported using table 3.2. Therefore, the use support rating is set to 'insufficient information'.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. One of the 2 samples exceed the Evaluation Guideline (USEPA Ambient Water Quality Criteria for Bacteria, 1986) as it applies to the Water Contact Recreation beneficial use. Neither sample exceeds the water quality objective for Non-Contact Recreation. The sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 26 samples is needed to determine if a beneficial use is fully supported using Table 3.2.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current cycle. The decision has not changed.
 
State Board Staff Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 84541, Escherichia coli (E. coli)
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80792
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Escherichia coli.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 2000/100 ml, nor shall more than ten percent of samples collected during any 30-day period exceed 4000/100 ml. E. coli is a fecal coliform.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/1/2004-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 84541, Escherichia coli (E. coli)
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80784
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 2
Number of Exceedances: 1
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 1 of 2 samples exceed the criterion for Escherichia coli.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: USEPA Ambient Water Quality Criteria for Bacteria -1986.
Objective/Criterion Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Evaluation Guideline: Single sample maximum allowable density for E. coli in freshwater is 235 MPN/100mL (as stated in Table 4, page 15)
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/1/2004-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
 
DECISION ID
84998
Region 3     
Los Osos Creek Estuary
 
Pollutant: Specific Conductivity
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Note: This decision was formerly associated with Los Osos Creek but in the 2014 assessment cycle was transferred to the newly mapped ¿Los Osos Creek Estuary¿, where the monitoring stations associated with the LOEs in this decision are located. The 'Listing Year' associated with every LOE is 2014, regardless of the year the LOE was created. This is because the old LOEs (pre 2014) were moved to this newly mapped water segment in 2014 and this process changed the date associated with the LOE in the assessment data base.

This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Note that the pollutant name for the older LOEs and decisions is electrical conductivity. This was an error and the pollutant name should have always been specific conductivity. For this reason, the pollutant name was changed for this decision.

One line of evidence is available in the administrative record to assess this pollutant. Two of the three samples exceed the water quality objective for agricultural uses. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 26 samples is needed to determine if a beneficial use is supported and a minimum of five exceedances is needed to determine if beneficial uses are not supported using table 3.2. Therefore, the use support rating is set to 'insufficient information'.

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

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Two of the three samples exceed the 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.
 
Regional Board Decision Recommendation: This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current cycle. The decision has not changed.
 
State Board Staff Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 84998, Specific Conductivity
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80771
 
Pollutant: Electrical Conductivity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Agricultural Supply
 
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 Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 2 of 3 samples exceed the criterion for Conductivity(Us).
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
 
DECISION ID
84908
Region 3     
Los Osos Creek Estuary
 
Pollutant: Temperature, water
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Note: This decision was formerly associated with Los Osos Creek but in the 2014 assessment cycle was transferred to the newly mapped ¿Los Osos Creek Estuary¿, where the monitoring stations associated with the LOEs in this decision are located. The 'Listing Year' associated with every LOE is 2014, regardless of the year the LOE was created. This is because the old LOEs (pre 2014) were moved to this newly mapped water segment in 2014 and this process changed the date associated with the LOE in the assessment data base.

This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Two Three lines of evidence are available in the administrative record to assess this pollutant. Sixteen of the 98 samples exceed the evaluation guideline (Moyle, 1976) used to interpret the water quality objective for water temperature.

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

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Sixteen of the 98 samples exceed the evaluation guideline and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Staff Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 84908, Temperature, water
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80761
 
Pollutant: Temperature, water
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 95
Number of Exceedances: 16
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 16 of 95 samples exceed the criterion for Water Temperature.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The optimum range for growth and completion of most life stages of rainbow trout is 13-21 degrees Celsius (Moyle 1976).
Guideline Reference: The Effects of Turbidity on Prey Selection by Piscivorous Largemouth Bass
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 84908, Temperature, water
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80759
 
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: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Water Temperature.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses (General Objective in Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline: Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).
Guideline Reference: Inland Fishes of California
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
 
DECISION ID
84771
Region 3     
Los Osos Creek Estuary
 
Pollutant: pH
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Note: This decision was formerly associated with Los Osos Creek but in the 2014 assessment cycle was transferred to the newly mapped ¿Los Osos Creek Estuary¿, where the monitoring stations associated with the LOEs in this decision are located. The 'Listing Year' associated with every LOE is 2014, regardless of the year the LOE was created. This is because the old LOEs (pre 2014) were moved to this newly mapped water segment in 2014 and this process changed the date associated with the LOE in the assessment data base.


This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Twelve lines of evidence are available in the administrative record to assess this pollutant. Six beneficial uses are assessed. Three of the 96 samples exceed the water quality objectives for Agriculture, Drinking Water and Recreation. Fifteen of the 96 samples exceed the water quality objectives for Cold and Warm Freshwater Habitats.

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

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Three of the 96 samples exceed the water quality objectives for Agriculture, Drinking Water and Recreation. Fifteen of the 96 samples exceed the water quality objectives for Cold and Warm Freshwater Habitats. These do not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Staff Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 84771, pH
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80802
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 93
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 3 of 93 samples exceed the criterion for pH.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The pH value shall neither be depressed below 6.5 nor raised above 8.3 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: pH was measured using test strips. In recent communication with the program QA officer concern has been raised about underestimation of the result with test strips.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 84771, pH
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80801
 
Pollutant: pH
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: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for pH.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 84771, pH
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80800
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 93
Number of Exceedances: 15
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 15 of 93 samples exceed the criterion for pH.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The pH value shall not be depressed below 7.0 or raised above 8.5 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: pH was measured using test strips. In recent communication with the program QA officer concern has been raised about underestimation of the result with test strips.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 84771, pH
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80796
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 93
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 3 of 93 samples exceed the criterion for pH.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The pH value shall not be depressed below 6.5 or raised above 8.3 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: pH was measured using test strips. In recent communication with the program QA officer concern has been raised about underestimation of the result with test strips.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 84771, pH
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80798
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for pH.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Central Coast Basin, Section II.A.2. Municipal and Domestic Supply Objectives, Section II.A.2.a states the following: The pH value shall neither be depressed below 6.5 or raised above 8.3.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 84771, pH
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80793
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 93
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 3 of 93 samples exceed the criterion for pH.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The pH value shall neither be depressed below 6.5 nor raised above 8.3 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: pH was measured using test strips. In recent communication with the program QA officer concern has been raised about underestimation of the result with test strips.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 84771, pH
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80795
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for pH.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 84771, pH
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80791
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 93
Number of Exceedances: 15
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 15 of 93 samples exceed the criterion for pH.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The pH value shall not be depressed below 7.0 or raised above 8.5 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: pH was measured using test strips. In recent communication with the program QA officer concern has been raised about underestimation of the result with test strips.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 84771, pH
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80788
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for pH.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 84771, pH
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80785
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for pH.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Central Coast Basin objective for water contact recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 84771, pH
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80787
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 93
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 3 of 93 samples exceed the criterion for pH.
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The pH value shall neither be depressed below 6.5 nor raised above 8.3 (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: pH was measured using test strips. In recent communication with the program QA officer concern has been raised about underestimation of the result with test strips.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 84771, pH
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80810
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for pH.
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
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 (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
 
DECISION ID
86744
Region 3     
Los Osos Creek Estuary
 
Pollutant: Turbidity
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Sources: Source Unknown
Expected TMDL Completion Date: 2023
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Note: This decision was formerly associated with Los Osos Creek but in the 2014 assessment cycle was transferred to the newly mapped ¿Los Osos Creek Estuary¿, where the monitoring stations associated with the LOEs in this decision are located. The 'Listing Year' associated with every LOE is 2014, regardless of the year the LOE was created. This is because the old LOEs (pre 2014) were moved to this newly mapped water segment in 2014 and this process changed the date associated with the LOE in the assessment data base.

This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Four lines of evidence are available in the administrative record to assess this pollutant. Nineteen of the 95 samples exceed the evaluation guideline for Cold Freshwater Habitat (Sigler et al. 1984) but only nine of the 95 samples exceed the Warm Freshwater Habitat evaluation guideline (Shoup, D.E. and Wahl D.H., 2009), both used to interpret the water quality objective for turbidity.

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

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Nineteen of the 95 samples exceed the evaluation guideline for Cold Freshwater Habitat and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
 
State Board Staff Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 86744, Turbidity
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80770
 
Pollutant: Turbidity
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: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Turbidity(NTU).
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline: Sigler et al. (1984) states that turbidities of 25 NTU's or greater caused reduction in juvenile salmonid growth due to interference with their ability to find food.
Guideline Reference: Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 86744, Turbidity
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80767
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 92
Number of Exceedances: 19
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 19 of 92 samples exceed the criterion for Turbidity(NTU).
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. (Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Turbidities of 25 NTU or greater can cause a reduction in juvenile salmonid growth due to interference with their ability to find food (Sigler et al. 1984).
Guideline Reference: Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150
 
Spatial Representation: Data for this line of evidence for Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2
 
Line of Evidence (LOE) for Decision ID 86744, Turbidity
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80762
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Los Osos Creek to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Turbidity(NTU).
Data Reference: Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)
 
Evaluation Guideline: Sigler et al. (1984) states that turbidities of 25 NTU's or greater caused reduction in juvenile salmonid growth due to interference with their ability to find food.
Guideline Reference: Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150
 
Spatial Representation: Data for this line of evidence for Los Osos Creek was collected at 1 monitoring site [ 310-SYB-41 - Santa Ysabel Bridge]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 86744, Turbidity
Region 3     
Los Osos Creek Estuary
 
LOE ID: 80758
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 92
Number of Exceedances: 9
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Region 3 - Central Coast Region staff assessed R3 public submissions data for Los Osos Creek Estuary to determine beneficial use support and results are as follows: 9 of 92 samples exceed the criterion for Turbidity(NTU).
Data Reference: Data from Morro Bay National Estuary Program's Volunteer Monitoring Program, May 2002-Apr. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Turbidities of 40 NTU or greater can cause a reduction in piscivorous fish (largemouth bass) growth due to interference with their ability to find food (Shoup, D.E. and Wahl D.H., 2009).
Guideline Reference: 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 Los Osos Creek Estuary was collected at 1 monitoring site [ 310SYB - Los Osos Creek Estuary, South Bay Blvd.]
Temporal Representation: Data was collected over the time period 6/23/2002 2:45:00 PM-3/5/2010 10:18:00 AM.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected in compliance with an EPA approved QAPP
QAPP Information Reference(s): Quality Assurance Project Plan for Morro Bay National Estuary Program¿s Volunteer Monitoring Program. Jan. 12, 2010, Version 5, Draft 2