Final California 2020 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 3 - Central Coast Region

Water Body Name: Los Osos Creek (upstream of Los Osos)
Water Body ID: CAR3102301120110722125030
Water Body Type: River & Stream
 
DECISION ID
114041
Region 3     
Los Osos Creek (upstream of Los Osos)
 
Pollutant: Oxygen, Dissolved
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2018)
Revision Status Revised
Sources: No Source Analysis Available
Expected TMDL Completion Date: 2035
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal from the 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.

Twenty-nine of 65 samples exceed the cold freshwater habitat water quality objective (Basin Plan). Seventeen of 48 samples exceed the water quality objective for fish spawning (Basin Plan), which exceeds that allowable frequency. Two of the 65 samples exceed the water quality objective for warm freshwater habitat (Basin Plan), which does not exceed the allowable frequency. Note that there is no difference between samples fractions ‘dissolved’ and ‘total,’ therefore sample and exceedance counts will be summed for the purpose of this decision.

Previous decisions (pre-2020) included dissolved oxygen saturation LOEs as ancillary evidence. This decision will no longer include dissolved oxygen saturation and these LOEs will be retired next cycle.

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

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Twenty-nine of 65 samples exceed the cold freshwater habitat objective and 17 of 48 samples exceed the fish spawning objective. 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 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 114041, Oxygen, Dissolved
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47964
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 17 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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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 114041, Oxygen, Dissolved
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 174599
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 48
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 2 of 48 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-04-08 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 114041, Oxygen, Dissolved
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 174968
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 48
Number of Exceedances: 17
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 17 of 48 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-04-08 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 114041, Oxygen, Dissolved
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 174450
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Fish Spawning
 
Number of Samples: 48
Number of Exceedances: 17
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 17 of 48 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-04-08 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 114041, Oxygen, Dissolved
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47962
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 7
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 7 of 17 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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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
132072
Region 3     
Los Osos Creek (upstream of Los Osos)
 
Pollutant: Benthic Community Effects
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Benthic Community Effects are being considered for placement on the CWA section 303(d) List under sections 3.9 of the Listing Policy. Under section 3.9, additional lines of evidence (LOEs) associating the Benthic Community Effects decision with a water or sediment concentration of pollutants other than benthic-macroinvertebrate bioassessment or habitat assessment LOEs are necessary to place a water body on the 303(d) List for Benthic Community Effects.

One line of evidence evaluating benthic-macroinvertebrate bioassessment data is/are available in the administrative record to assess this indicator. Zero of two benthic-macroinvertebrate samples exceed the California Stream Condition Index (CSCI) impairment threshold. These data indicate that the waterbody is likely unimpaired for Benthic Community Effects and therefore no other pollutant LOEs need be associated with this decision at this time.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing Benthic Community Effects in this waterbody segment on the CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Zero of two benthic-macroinvertebrate bioassessment samples had CSCI scores below 0.79. Therefore, this water body is not exceeding the water quality threshold for the protection of the COLD beneficial use. The available information indicates that the waterbody/pollutant combination should not be placed on the 303(d) List of impaired waters at this time.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards for the pollutant are not exceeded.
 
 
Line of Evidence (LOE) for Decision ID 132072, Benthic Community Effects
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 233387
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: Water Board staff assessed data for 310CLK to determine beneficial use support and the results are as follows: 0 of 2 samples exceeded the threshold. CSCI scores were from 0.849552 to 1.06234.
Data Reference: California Stream Condition Index (CSCI) Scores for the 2020 Integrated Report for Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. Region 3 Basin Plan.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The California Stream Condition Index (CSCI) is a biological scoring tool that helps aquatic resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score is calculated by comparing the expected condition with actual (observed) results (Rehn, A.C. et al., 2015). CSCI scores range from 0 (highly degraded) to greater than 1 (equivalent to reference). CSCI scoring of biological condition are as follows (per the scientific paper supporting the development of the CSCI scoring tool): greater than or equal to 0.92 = likely intact condition, 0.91 to 0.80 = possibly altered condition, 0.79 to 0.63 = likely altered condition, less than or equal to 0.62 = very likely altered condition. Sites with scores below 0.79 are considered to have exceeded the water quality objective for the aquatic life beneficial use.  
Guideline Reference: Bioassessment in complex environments: designing an index for consistent meaning in different settings
 
Spatial Representation: Samples were collected from station 310CLK.
Temporal Representation: Samples were collected from 6/2/2011 to 6/7/2012.
Environmental Conditions:
QAPP Information: Data collected following Morro Bay National Estuary Program's Monitoring Program protocols.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
 
DECISION ID
125698
Region 3     
Los Osos Creek (upstream of Los Osos)
 
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)(2018)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the ISWEBE Plan) contains two bacteria water quality objectives applicable to the REC-1 beneficial use, which were adopted on August 7, 2018. Because the salinity level of this waterbody is equal to or less than 1 part per thousand 95 percent or more of the time, the E. coli bacteria objective applies. Therefore, this waterbody is being considered for placement on the CWA section 303(d) List under section 3.3 of the Listing Policy, as applicable, using the E. coli objective.

In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. E. coli populations may fluctuate substantially on a daily, seasonal, or yearly basis. Lacking constant inputs, indicator bacteria do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of E. coli in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard.

Additionally, water quality conditions in waterbodies may change as a result of management actions that have been implemented to address E. coli. Unrepresentative data may result in incorrectly placing or not placing a water body segment on the CWA section 303(d) List, which could result in the unnecessary expenditure of public resources or missing a human health problem. Historic lines of evidence for data collected prior to 2010 were evaluated pursuant to these considerations and were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy.

All samples are evaluated using the statistical threshold value (STV) water quality objective for water contact recreation (ISWEBE, SWRCB 2019). The water quality objective states that the STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month. Where there are more than one samples collected within any six-week period, a geomean of those samples is calculated and evaluated using the geomean water quality objective for water contact recreation (ISWEBE, SWRCB 2019).

Although two lines of evidence are available in the administrative record to assess this pollutant, this decision is based upon evaluation of the E. coli data collected since 2010 which are most representative of existing conditions in the waterbody. Seven of the 49 samples collected since 2010 exceed the STV water quality objective (see LOE 149942) and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. No geomeans could be calculated for these data. The data were collected between 2010 and 2018 and represent a range of hydrologic conditions (both wet and dry years). This sample count of data collected since 2010 is adequate to determine beneficial use support in accordance with the Listing Policy.

Note, there is one line of evidence summarizing historic data (data collected prior to 2010) compared to the USEPA’s Ambient Water Quality Criteria for Bacteria (USEPA, 1986). Zero of the 19 historic samples exceed the USEPA criteria set to protect for water contact recreation. These data are not used for making this decision or used in the final use support ratings.

After review of the available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) List in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Seven out of the 49 samples exceed water quality objective (ISWEBE, SWRCB 2019) for water contact recreation and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) List because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation: Although two lines of evidence are available in the administrative record to assess this pollutant, this decision is based upon evaluation of the E. coli data collected since 2010 which are most representative of existing conditions in the waterbody. Seven of the 49 samples collected since 2010 exceed the STV water quality objective (see LOE 149942) and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. No geomeans could be calculated for these data. The data were collected between 2010 and 2018 and represent a range of hydrologic conditions (both wet and dry years). This sample count of data collected since 2010 is adequate to determine beneficial use support in accordance with the Listing Policy.

Note, there is one line of evidence summarizing historic data (data collected prior to 2010) compared to the USEPA’s Ambient Water Quality Criteria for Bacteria (USEPA, 1986). Zero of the 19 historic samples exceed the USEPA criteria set to protect for water contact recreation. These data are not used for making this decision or used in the final use support ratings.

After review of the available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) List in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Seven out of the 49 samples exceed water quality objective (ISWEBE, SWRCB 2019) for water contact recreation 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.
 
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 125698, Escherichia coli (E. coli)
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47947
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 19
Number of Exceedances: 0
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 19 samples exceed the criterion for Escherichia coli.
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 E. coli in freshwater is 235 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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/5/2008 8:05:00 AM-2/11/2010 10:50:00 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 125698, Escherichia coli (E. coli)
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 149942
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 49
Number of Exceedances: 7
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and the results are as follows: 7 of the 49 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective applicable to all non-saline waters, is a Statistical Threshold Value (STV) of 320 cfu/100 mL. The applicable STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month, calculated in a static manner (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 310CLV
Temporal Representation: The samples were collected between the days of 2010-04-08 and 2017-09-25 .
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
 
DECISION ID
126814
Region 3     
Los Osos Creek (upstream of Los Osos)
 
Pollutant: Nitrate
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)(2018)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Eight lines of evidence are available in the administrative record to assess this pollutant. Lines of evidence for the pollutant name Nitrate and for the pollutant name Nitrogen, Nitrate are combined and sample and exceedance counts are summed for the purpose of making this decision.

Zero of the 26 nitrate samples exceed the water quality objectives for the Agricultural Supply and Municipal and Domestic Supply beneficial uses. Two of the 26 nitrate samples exceed the water quality objectives for Cold and Warm Freshwater Habitat.

The Central Coast Region requires supporting evidence of eutrophication to support a nitrate listing at 1.0 mg/L for Cold and Warm Freshwater Habitat. There is insufficient evidence that the Cold or Warm Freshwater Habitat beneficial uses are impaired. The following is a summary of the supporting evidence:
1) Dissolved oxygen for this water body ranged from 3.4 mg/L to 11.35 mg/L, twice exceeding (falling below) the Cold Freshwater Habitat water quality objective of 7.0 mg/L.

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

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Zero of the 26 nitrate samples exceed the water quality objectives for the Agricultural Supply and Municipal and Domestic Supply beneficial uses. Two of the 26 nitrate samples exceed the water quality objectives for Cold and Warm Freshwater Habitat. There is insufficient supporting evidence of eutrophication, these do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 126814, Nitrate
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47948
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 18
Number of Exceedances: 0
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 18 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 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 for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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 126814, Nitrate
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 172913
 
Pollutant: Nitrogen, Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 8
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Nitrate as N.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
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 (Water Quality Control Plan, Central Coast Basin).
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: 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: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2016-03-15 and 2018-06-20
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 126814, Nitrate
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 172889
 
Pollutant: Nitrogen, Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 8
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Nitrate as N.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
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 listed in the Central Coast Basin Plan and identified as the level 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 for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2016-03-15 and 2018-06-20
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 126814, Nitrate
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 172883
 
Pollutant: Nitrogen, Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 8
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Nitrate as N.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: All inland surface waters, enclosed bays, and estuaries shall not contain concentrations of inorganic chemicals in excess of the maximum contaminant levels for primary drinking water standards specified in California Code of Regulations, Title 22, Division 4, Chapter 15, Sections 64431 and 64433.2.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The California Maximum Contaminant Level for nitrate (as N) 10.0 mg/L (California Code of Regulations, Title 22).
Guideline Reference: California MCLs - Title 17 and Title 22 documents for 2019 - California Regulations Related to Drinking Water
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2016-03-15 and 2018-06-20
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 126814, Nitrate
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 172319
 
Pollutant: Nitrogen, Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 8
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Nitrate as N.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
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 (Water Quality Control Plan, Central Coast Basin).
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: 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: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2016-03-15 and 2018-06-20
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 126814, Nitrate
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47961
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 18
Number of Exceedances: 2
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 2 of 18 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
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: Data for this line of evidence for Los Osos Creek (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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 126814, Nitrate
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47949
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 18
Number of Exceedances: 2
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 2 of 18 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
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: Data for this line of evidence for Los Osos Creek (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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 126814, Nitrate
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47960
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 18
Number of Exceedances: 0
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 18 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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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
 
 
DECISION ID
126339
Region 3     
Los Osos Creek (upstream of Los Osos)
 
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)(2018)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the Clean Water Act (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.

A total of two lines of evidence are available in the administrative record to assess this pollutant. Sample and exceedance counts for the lines of evidence with the fraction identified as “none” or “not recorded” are grouped together with those having the fraction “total”, based on the analytical method used. Once summed, a total of zero of 64 samples exceed the water quality objective for agricultural supply. Note that the pollutant name for the older LOEs is electrical conductivity. This was an error and the pollutant name should have always been specific conductivity. For this reason, all two of the LOEs are combined into this assessment for specific conductivity.

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.

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. A total of zero of 64 samples exceed the water quality objective for agricultural supply and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 126339, Specific Conductivity
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 182641
 
Pollutant: Specific Conductivity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 47
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 47 samples exceeded the water quality threshold for SpecificConductivity.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
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 listed in the Central Coast Basin Plan and identified as the level at which severe problems may occur when EC exceeds 3.0 mmho/cm in irrigation supply water (meaurements reported at 25 degrees C). EC measured, at 25 degrees C , is referred to as specific conductivity. Also note that 1 mmho/cm = 1000 uS/cm.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-04-08 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 126339, Specific Conductivity
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47946
 
Pollutant: Specific Conductivity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 17
Number of Exceedances: 0
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 17 samples exceed the criterion for Conductivity(Us).
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 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 3000 uS/cm in irrigation supply water.
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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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
126241
Region 3     
Los Osos Creek (upstream of Los Osos)
 
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)(2018)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the Clean Water Act (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.

A total of two lines of evidence are available in the administrative record to assess this pollutant. A total of zero of 64 samples exceed the evaluation guideline (Moyle 1976) applied to protect the cold freshwater habitat beneficial use.

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.

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. A total of zero of 64 samples exceed the evaluation guideline applied to protect the cold freshwater habitat beneficial use and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 126241, Temperature, water
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 216757
 
Pollutant: Temperature, water
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 47
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 47 samples exceeded the water quality threshold for Temperature.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
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 (Water Quality Control Plan, Central Coast Basin).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: The optimum range for growth and completion of most life stages of rainbow trout is 13-21 degrees Celsius (Moyle 1976).
Guideline Reference: Inland Fishes of California
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-04-08 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 126241, Temperature, water
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47994
 
Pollutant: Temperature, water
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 17 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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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
114043
Region 3     
Los Osos Creek (upstream of Los Osos)
 
Pollutant: Turbidity
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)(2018)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the Clean Water Act (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.

A total of four lines of evidence are available in the administrative record to assess this pollutant. Sample and exceedance counts for the lines of evidence with the fraction identified as “none” or “not recorded” are grouped together with those having the fraction “total”, based on the analytical method used. Once summed, a total of one of 63 samples exceed the evaluation guideline for cold freshwater habitat (Sigler et al. 1984) and one of 63 samples exceed the evaluation guideline for warm freshwater habitat (Shoup, D.E. and Wahl D.H., 2009) used to interpret the water quality objectives for the aquatic life beneficial uses.

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.

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. A total of one of 63 samples exceed the evaluation guideline for cold freshwater habitat and one of 63 samples exceed the evaluation guideline for warm freshwater habitat and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 114043, Turbidity
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47992
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 17 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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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 114043, Turbidity
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47993
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 17
Number of Exceedances: 0
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 17 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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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 114043, Turbidity
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 182008
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 46
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 1 of 46 samples exceeded the water quality threshold for Turbidity.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
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: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-04-08 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 114043, Turbidity
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 182090
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 46
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 1 of 46 samples exceeded the water quality threshold for Turbidity.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
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).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Turbidities of 40 NTU or greater can cause a reduced foraging efficiency and a shift in prey selection in piscivorous fish (largemouth bass) due to interference with their ability to find prey (Shoup, D.E. and Wahl D.H., 2009).
Guideline Reference: The Effects of Turbidity on Prey Selection by Piscivorous Largemouth Bass
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-04-08 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
 
DECISION ID
114042
Region 3     
Los Osos Creek (upstream of Los Osos)
 
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)(2018)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Twelve lines of evidence is available in the administrative record to assess this pollutant. One of the 61 samples exceed the maximum pH water quality objective for Agriculture Supply, Municipal and Domestic Supply, Contact and Non-contact Recreation beneficial uses. Five of the 61 samples exceed the maximum pH water quality objectives for Cold and Warm Freshwater Habitat.

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

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. One of the 61 samples exceed the maximum pH water quality objective for Agriculture Supply, Municipal and Domestic Supply, Contact and Non-contact Recreation beneficial uses and 5 of the 61 samples exceed the maximum pH water quality objectives for Cold and Warm Freshwater Habitat and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) List because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 114042, pH
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47976
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 18
Number of Exceedances: 0
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 18 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: 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 Region 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 for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Los Osos Creek (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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 114042, pH
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47977
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 18
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 3 of 18 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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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 114042, pH
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47978
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 18
Number of Exceedances: 0
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 18 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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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 114042, pH
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47980
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 18
Number of Exceedances: 0
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 18 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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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 114042, pH
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47991
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 18
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 3 of 18 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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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 114042, pH
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 178560
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 43
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 2 of 43 samples exceeded the water quality threshold for pH.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Central Coast Basin objective for warm fresh water habitat (Section 3.3.2 Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries) states that the pH value shall neither be depressed below 7.0 nor raised above 8.5.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-07-15 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 114042, pH
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 177970
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 43
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 1 of 43 samples exceeded the water quality threshold for pH.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
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 listed in the Central Coast Basin Plan and identified as the level 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 for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-07-15 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 114042, pH
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 178056
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 43
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 1 of 43 samples exceeded the water quality threshold for pH.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Central Coast Basin objective for municipal and domestic supply (Section 3.3.2 Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries) states that the pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-07-15 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 114042, pH
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 177744
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 43
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 1 of 43 samples exceeded the water quality threshold for pH.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Central Coast Basin objective for water contact recreation (Section 3.3.2 Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries) states that the pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-07-15 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 114042, pH
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 177783
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 43
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 1 of 43 samples exceeded the water quality threshold for pH.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation (Section 3.3.2 Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries) states that the pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-07-15 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 114042, pH
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 178031
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 43
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Morro Bay NEP Monitoring Program data for Los Osos Creek (upstream of Los Osos) to determine beneficial use support and results are as follows: 2 of 43 samples exceeded the water quality threshold for pH.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Central Coast Basin objective for cold fresh water habitat (Section 3.3.2 Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries) states that the pH value shall neither be depressed below 7.0 nor raised above 8.5.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (310CLV)
Temporal Representation: The samples were collected between the dates of 2010-07-15 and 2018-11-19
Environmental Conditions:
QAPP Information: Morro Bay National Estuary Program. 2018. QAPP for Morro Bay National Estuary Program's Monitoring Program.
QAPP Information Reference(s): QAPP for Morro Bay National Estuary Program's Monitoring Program
 
Line of Evidence (LOE) for Decision ID 114042, pH
Region 3     
Los Osos Creek (upstream of Los Osos)
 
LOE ID: 47979
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 18
Number of Exceedances: 0
 
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 (upstream of Los Osos) to determine beneficial use support and results are as follows: 0 of 18 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 (upstream of Los Osos) was collected at 1 monitoring site [ 310CLV - Clark Valley Road, Los Osos Creek]
Temporal Representation: Data was collected over the time period 3/20/2008 9:30:00 AM-2/11/2010 10:32:00 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