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

# Supporting Information

## Regional Board 3 - Central Coast Region

Water Body Name: | Morro Bay
Water Body ID: | CAB3102201219980827141506
Water Body Type: | Bay & Harbor

DECISION ID | 4866
Pollutant: | Metals
Final Listing Decision: | Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Delist from 303(d) list (TMDL required list)(2006)
Revision Status | Original
Reason for Delisting: | Flaws in original listing
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This combined pollutant listing is being considered for removal from the section 303(d) list under section 4 of the Listing Policy. The Policy calls for the delisting of waters if the decision is found to be faulty and it is demonstrated that the listing would not have occurred in the absence of such faulty data. Nine different lines of evidence are available in the administrative record to assess this pollutant listing. The listing included Aluminum, Arsenic, Cadmium, Chromium, and Mercury, which were combined into one listing originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of section 6.1.3 the Listing Policy. With the exception of Arsenic, determination of exceedances for the remaining metals (individually evaluated) were either not possible because no criteria or guidelines were available but also no exceedances were recorded when compared with applicable acceptable standards either. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of removing this water segment-pollutants combination for metals from the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that the guidelines used to assess the status of this water body for the set of metals evaluated does not meet the requirement of the Listing Policy but no exceedances were recorded when each metal was evaluated using acceptable guidelines. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should be removed from the section 303(d) list because applicable water quality standards for the pollutant are not exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4866

LOE ID: | 90
Pollutant: | Mercury
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Estuarine Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | None of the five samples taken in Morro Bay exceeded because there are no guidelines for dissolved mercury in the saltwater column that meet the requirements of the Listing Policy (Keeling, 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Waters shall not contain suspended material in concentrations that cause nuisance or adversely affect beneficial uses. Waters shall not contain settleable material in concentrations that result in deposition of material that causes nuisance or adversely affects beneficial uses.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | There are no acute or chronic criteria for dissolved mercury in saltwater that meets the requirements of the Listing Policy.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Water was sampled from five (5) separate locations meant to represent the back, middle and front of the Bay and were also meant to represent the flow from the two creeks that feed the Bay (sites were Front Bay, Middle Bay, Back Bay, Mouth Chorro and Mouth Los Osos. The stations are: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: |
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 88
Pollutant: | Chromium (total)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Estuarine Habitat
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | None of the five samples taken can be compared with the established water quality objective because the established water quality objective is in the total form of chromium and the available data is reported in the dissolved fraction (Keeling, 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | There is no evaluation guideline for the dissolved fraction of chromium for the protection of aquatic like in marine waters that meets the requirements of the Listing Policy.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Water was sampled from five (5) separate locations representing the back, middle and front of the Bay including inflows from the mouth of Chorro and the mouth of Los Osos creeks that feed into the Bay. The stations are: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: | This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy.
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 79
Pollutant: | Metals
LOE Subgroup: | Testimonial Evidence
Matrix: | Not Specified
Fraction: | None
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Regional Board staff recommends delisting Morro Bay for metals based on the fact that (Keeling, S. 2003): ·Water quality objectives are currently being met in the water column, ·Metals present in the sediment appear to be the natural result of local geology and do not represent pollution, ·Levels of metals in tissue appear to be at reasonable levels considering the natural geology of the area, and ·There appears to be no correlation between the concentration of metals in the sediment and the water above it.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Request for delisting. Applicable WQO or criterion: ·Basin Plans water quality objectives for marine water ·Basin Plans narrative objective for settleable and suspended material ·California Toxics Rule (Federal Register. Volume 65, No. 97. Part III. Environmental Protection Agency, 40 CFR Part 131. Water Quality Standards; Establishment of Numeric Criteria for Priority Toxic Pollutants for the State of California; Rule. Thursday, May 18, 2000.)
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Morro Bay (Calwater watershed 31023012), located on the central coast of California, about 60 miles north of Point Conception and about 100 miles south of Monterey Bay in San Luis Obispo County.
Temporal Representation: | Submittal on 6/14/2004.
Environmental Conditions: |
QAPP Information: | All sampling, collection and analysis followed the Regional Board's Central Coast Ambient Monitoring Program's (CCAMP) Quality Assurance Plan. Please talk to staff, Shanta Keeling, for more details if necessary.
QAPP Information Reference(s):
LOE ID: | 86
Pollutant: | Cadmium
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Estuarine Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | None of five samples taken in Morro Bay exceeded any CTR criteria for dissolved cadmium in saltwater. Cadmium concentrations ranged from 0.0686 to 0.0349 ug/L (Keeling, 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Waters shall not contain suspended material in concentrations that cause nuisance or adversely affect beneficial uses. Material Waters shall not contain settleable material in concentrations that result in deposition of material that causes nuisance or adversely affects beneficial uses. Water quality objective in marine environment - total concentration 0.2 ppb.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | CTR Saltwater acute 42 ug/L Criterion Maximum Concentration (CMC) and saltwater chronic 9.3 ug/L Criterion Continuous Concentration (CCC) criteria is applicable.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Water was sampled from five (5) separate locations representing the back, middle and front of the Bay including the inflows from the mouth Chorro and the mouth of Los Osos creeks that feed into the Bay. The stations were: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: | This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy.
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 87
Pollutant: | Chromium (total)
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | None of the 12 samples could be evaluated because there are no numeric criteria or guidelines that meets the requirements of the Listing Policy for chromium in tissue (Keeling, 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | There is no numeric criteria or guideline that meets the requirements of the Listing Policy for chromium in tissue.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Four sites were sampled on Morro Bay: 427.0, 428.5, 429.0, and 429.2.
Temporal Representation: | Site 429.0 was sampled on 6/28/1982, 1/21/1983 and 5/3/1983. Site 429.2 was sampled on 1/26/1987, 3/14/1988, 12/19/1988, 2/2/1990 and 1/20/1993. Sampling for all other sites occurred from 5-30-98 to 1-20-93.
Environmental Conditions: | This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy.
QAPP Information: | State Mussel Watch Program Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 81
Pollutant: | Aluminum
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Originally, one out of 12 analyzed samples exceeded the EDL 85 of 138.43 ppm. However, no exceedances are currently recorded because there are no criteria or guidelines for aluminum in tissue that meet the requirements of the Listing Policy (Keeling, 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | There are no tissue criteria for Aluminum.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | There were four stations sampled: 427.0, 428.5, 429.0 and 429.2.
Temporal Representation: | Site 429.0 was sampled on 6/28/1982, 1/21/1983 and 5/3/1983. Site 429.2 was sampled on 1/26/1987, 3/14/1988, 12/19/1988, 2/2/1990 and 1/20/1993. Site 427.0 was sampled 5-30-1980 and 12-14-1980. Site 428.5 was sampled 5-30-1980 and 12-14-1980.
Environmental Conditions: | This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy (section 6.1.3.2).
QAPP Information: | State Mussel Watch Program Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 89
Pollutant: | Mercury
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | None of the 12 samples exceeded the OEHHA screening value at the 4 sampling stations (Keeling, 2003). This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy. Two samples out of eight were found to be above the EDL 85 values (0.06 ppm) with concentrations of 0.136 ppm and 0.061 ppm wet weight on 1/26/1987 and 1/20/1993 respectively. Both samples were taken at site 429.2.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | OEHHA screening values of 0.3 ppm.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Four sites were sampled on Morro Bay: 427.0, 428.5, 429.0, and 429.2.
Temporal Representation: | Sampling occurred from 5-30-1980 to 1-20-1993.
Environmental Conditions: |
QAPP Information: | State Mussel Watch Program Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 82
Pollutant: | Aluminum
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | No exceedances were recorded for all 5 samples because there are no criterion or guidelines for the dissolved fraction of aluminum that meet the requirements of the Listing Policy (Keeling, 2003). This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Waters shall not contain suspended material in concentrations that cause nuisance or adversely affect beneficial uses. Waters shall not contain settleable material in concentrations that result in deposition of material that causes nuisance or adversely affects beneficial uses.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | The CTR criteria for the dissolved fraction of selected metals are applicable for the protection of aquatic life but there are no criteria or guidelines for the dissolved fraction of aluminum that meet the requirements of the Listing Policy.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | There were five sampling sites throughout Morro Bay. Locations represented the back, middle, and front of the Bay including inflows from Chorro and Los Osos Creeks. The stations were: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: |
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 85
Pollutant: | Cadmium
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | None of 12 samples from the 4 stations were in exceedance when the data was reevaluated using USEPA and OEHHA criteria (Keeling, S. 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | USEPA standard of 4.0 ppm (wet weight) and OEHHA standard of 3.0 ppm (wet weight).
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Four sites were sampled on Morro Bay: 427.0, 428.5, 429.0, and 429.2.
Temporal Representation: | Sampling occurred from 5-30-1980 to 1-20-1993.
Environmental Conditions: | This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy. Site 429.2, on 1/26/1987, 3/14/1988, 12/19/1988, 2/2/1990 and 1/20/1993 had levels over the MIS values (levels ranged from 1.01 - 1.23 ppm wet weight). Five out of five samples at site 429.2 were over MIS. One out of three samples were above MIS values at site 429.0 (6/28/1982, 1.17 ppm wet weight).
QAPP Information: | State Mussel Watch Program Quality Assurance Plan.
QAPP Information Reference(s):

DECISION ID | 4652
Pollutant: | Aluminum
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.5 of the Listing Policy. Under section 3.5 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Aluminum is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy. The CTR criteria for the dissolved fraction of selected metals are applicable for the protection of aquatic life but there is no CTR criterion for dissolved aluminum and there is no criterion or guideline for aluminum in tissue that meets the requirement of the Listing Policy. 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 by it self 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. No exceedances of CTR criteria were recorded and no exceedances of aluminum in tissue were recorded because there is no criterion or guidelines for the dissolved fraction of aluminum or aluminum in tissue that meet the requirements 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 met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there is no criteria or guidelines that meet the requirements of section 6.1.3 of the Listing Policy and it cannot be determined if applicable water quality standards or guidelines are exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4652

LOE ID: | 81
Pollutant: | Aluminum
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Originally, one out of 12 analyzed samples exceeded the EDL 85 of 138.43 ppm. However, no exceedances are currently recorded because there are no criteria or guidelines for aluminum in tissue that meet the requirements of the Listing Policy (Keeling, 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | There are no tissue criteria for Aluminum.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | There were four stations sampled: 427.0, 428.5, 429.0 and 429.2.
Temporal Representation: | Site 429.0 was sampled on 6/28/1982, 1/21/1983 and 5/3/1983. Site 429.2 was sampled on 1/26/1987, 3/14/1988, 12/19/1988, 2/2/1990 and 1/20/1993. Site 427.0 was sampled 5-30-1980 and 12-14-1980. Site 428.5 was sampled 5-30-1980 and 12-14-1980.
Environmental Conditions: | This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy (section 6.1.3.2).
QAPP Information: | State Mussel Watch Program Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 82
Pollutant: | Aluminum
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | No exceedances were recorded for all 5 samples because there are no criterion or guidelines for the dissolved fraction of aluminum that meet the requirements of the Listing Policy (Keeling, 2003). This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Waters shall not contain suspended material in concentrations that cause nuisance or adversely affect beneficial uses. Waters shall not contain settleable material in concentrations that result in deposition of material that causes nuisance or adversely affects beneficial uses.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | The CTR criteria for the dissolved fraction of selected metals are applicable for the protection of aquatic life but there are no criteria or guidelines for the dissolved fraction of aluminum that meet the requirements of the Listing Policy.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | There were five sampling sites throughout Morro Bay. Locations represented the back, middle, and front of the Bay including inflows from Chorro and Los Osos Creeks. The stations were: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: |
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):

DECISION ID | 4653
Pollutant: | Arsenic
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under sections 3.5 of the Listing Policy. Under section 3.5 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is not sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The CTR, USEPA and OEHHA screening values used complies with the requirements of section 6.1.3 of the Policy. 2. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 3. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 4. None of five water column samples exceeded the CTR Saltwater acute (CMC) and saltwater chronic (CCC) criteria, and none of 2 tissue samples exceeded the USEPA criteria for inorganic arsenic and these do not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are being met.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4653

LOE ID: | 83
Pollutant: | Arsenic
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Evaluation of the inorganic arsenic clam tissue data using the USEPA criteria resulted in 2 of 2 samples not exceeding the criteria. Sampling station 429.0, outside of the mouth of the Bay recorded levels of 0.145 ppm and 0.174 ppm inorganic arsenic. Tissue were measured at 1.45 and 1.74 ppm as total arsenic (Keeling, 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | The USEPA criteria for inorganic arsenic is 1.2 ppm wet weight and the OEHHA criteria is 1.0 ppm wet weight for total arsenic.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Four sites were sampled on Morro Bay. One station was evaluated for this listing: 429.0. There were a total of 4 sampling stations: 427.0, 428.5, 429.0 and 429.2.
Temporal Representation: | Site 429.0 was sampled on 6/28/1982, 1/21/1983 and 5/3/1983. Sampling for the remaining three stations occurred from 5-30-1980 to 1-20-1993.
Environmental Conditions: | This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy.
QAPP Information: | State Mussel Watch Program Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 84
Pollutant: | Arsenic
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Estuarine Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | None of the five samples taken at the 5 stations exceeded any of the CTR dissolved arsenic criteria in the water column (Keeling, 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Waters shall not contain suspended material in concentrations that cause nuisance or adversely affect beneficial uses. Waters shall not contain settleable material in concentrations that result in deposition of material that causes nuisance or adversely affects beneficial uses.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | CTR saltwater acute 69 ug/l Criterion Maximum Concentration (CMC) and saltwater chronic 36 ug/l Criterion Continuous Concentration (CCC) criteria are applicable for the protection of aquatic life.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Water was sampled from five (5) separate locations representing the back, middle and front of the Bay including inflows from the mouths of Chorro and Los Osos Creeks who each feed the Bay. These stations were: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: |
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):

DECISION ID | 4644
Pollutant: | Barium
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality standards because there is no dissolved barium water quality objective, guideline or criteria for the protection of aquatic live in marine waters. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of the five samples exceeded any applicable standard. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because there is no water quality objective, criteria or guideline that meets the requirements of section 6.1.3 of the Listing Policy and it cannot be determined if applicable water quality standards are exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4644

LOE ID: | 93
Pollutant: | Barium
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Estuarine Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | None of the five samples taken in Morro Bay, were in exceedance because there is no barium criterion or guideline for barium in marine waters (Keeling, S. 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Waters shall not contain suspended material in concentrations that cause nuisance or adversely affect beneficial uses. Waters shall not contain settleable material in concentrations that result in deposition of material that causes nuisance or adversely affects beneficial uses.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Water was sampled from five (5) separate locations representing the back, middle and front of the Bay including inflows from the mouth Chorro and the mouth Los Osos creeks that feed into the Bay. The stations were: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: |
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):

DECISION ID | 4654
Pollutant: | Cadmium
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.5 of the Listing Policy. Under section 3.5 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Cadmium is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy. The CTR cadmium saltwater acute 42 ug/l Criterion Maximum Concentration (CMC) and saltwater chronic 9.3 ug/l Criterion Continuous Concentration (CCC) criteria as well as the cadmium USEPA standard of 4.0 ppm (wet weight) and OEHHA standard of 3.0 ppm (wet weight) are applicable. 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 by itself 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. None of the 5 water samples were in exceedance of the CTR criteria and none of the 12 tissue samples were in exceedance of the USEPA and OEHHA standards. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards for the pollutant are not exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4654

LOE ID: | 86
Pollutant: | Cadmium
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Estuarine Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | None of five samples taken in Morro Bay exceeded any CTR criteria for dissolved cadmium in saltwater. Cadmium concentrations ranged from 0.0686 to 0.0349 ug/L (Keeling, 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Waters shall not contain suspended material in concentrations that cause nuisance or adversely affect beneficial uses. Material Waters shall not contain settleable material in concentrations that result in deposition of material that causes nuisance or adversely affects beneficial uses. Water quality objective in marine environment - total concentration 0.2 ppb.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | CTR Saltwater acute 42 ug/L Criterion Maximum Concentration (CMC) and saltwater chronic 9.3 ug/L Criterion Continuous Concentration (CCC) criteria is applicable.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Water was sampled from five (5) separate locations representing the back, middle and front of the Bay including the inflows from the mouth Chorro and the mouth of Los Osos creeks that feed into the Bay. The stations were: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: | This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy.
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 85
Pollutant: | Cadmium
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | None of 12 samples from the 4 stations were in exceedance when the data was reevaluated using USEPA and OEHHA criteria (Keeling, S. 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | USEPA standard of 4.0 ppm (wet weight) and OEHHA standard of 3.0 ppm (wet weight).
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Four sites were sampled on Morro Bay: 427.0, 428.5, 429.0, and 429.2.
Temporal Representation: | Sampling occurred from 5-30-1980 to 1-20-1993.
Environmental Conditions: | This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy. Site 429.2, on 1/26/1987, 3/14/1988, 12/19/1988, 2/2/1990 and 1/20/1993 had levels over the MIS values (levels ranged from 1.01 - 1.23 ppm wet weight). Five out of five samples at site 429.2 were over MIS. One out of three samples were above MIS values at site 429.0 (6/28/1982, 1.17 ppm wet weight).
QAPP Information: | State Mussel Watch Program Quality Assurance Plan.
QAPP Information Reference(s):

DECISION ID | 4768
Pollutant: | Chromium (total)
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.5 of the Listing Policy. Under section 3.5 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Cadmium is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy. There are also no evaluation guideline for the dissolved fraction of chromium for the protection of aquatic life in marine waters that meets the requirements of the Listing Policy. 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 by it self 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. None of the five samples taken can be compared with the established water quality objective because the established water quality objective available for comparison is in the total form of chromium and the available data is reported in the dissolved fraction. None of the 12 tissue samples could also not be evaluated because there is no numeric criteria or guideline that meets the requirements of the Listing Policy for chromium in tissue. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because there is no water quality objective, criteria or guideline available that will allow determination of whether water quality standards are exceeded..
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4768

LOE ID: | 88
Pollutant: | Chromium (total)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Estuarine Habitat
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | None of the five samples taken can be compared with the established water quality objective because the established water quality objective is in the total form of chromium and the available data is reported in the dissolved fraction (Keeling, 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | There is no evaluation guideline for the dissolved fraction of chromium for the protection of aquatic like in marine waters that meets the requirements of the Listing Policy.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Water was sampled from five (5) separate locations representing the back, middle and front of the Bay including inflows from the mouth of Chorro and the mouth of Los Osos creeks that feed into the Bay. The stations are: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: | This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy.
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 87
Pollutant: | Chromium (total)
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | None of the 12 samples could be evaluated because there are no numeric criteria or guidelines that meets the requirements of the Listing Policy for chromium in tissue (Keeling, 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | There is no numeric criteria or guideline that meets the requirements of the Listing Policy for chromium in tissue.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Four sites were sampled on Morro Bay: 427.0, 428.5, 429.0, and 429.2.
Temporal Representation: | Site 429.0 was sampled on 6/28/1982, 1/21/1983 and 5/3/1983. Site 429.2 was sampled on 1/26/1987, 3/14/1988, 12/19/1988, 2/2/1990 and 1/20/1993. Sampling for all other sites occurred from 5-30-98 to 1-20-93.
Environmental Conditions: | This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy.
QAPP Information: | State Mussel Watch Program Quality Assurance Plan.
QAPP Information Reference(s):

DECISION ID | 4770
Pollutant: | Copper
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.5 of the Listing Policy. Under section 3.5 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. The CTR copper saltwater acute 4.8 ug/l Criterion Maximum Concentration (CMC) and saltwater chronic 3.1 ug/l Criterion Continuous Concentration (CCC) criteria as well as the copper USFWS effects value of 15 ppm (wet weight) are applicable. 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. This conclusion is based on the staff findings that: 1.The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2.The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of the five water samples taken exceeded any of the CTR dissolved copper criteria in the water column. Dissolved copper concentrations ranged from 0.815 to0.262 ug/l. There were also no exceedances for the 12 copper samples in tissue. Tissue concentration measured from 0.76 to 3.13 ppm. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards for the pollutant are not exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4770

LOE ID: | 92
Pollutant: | Copper
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Not Recorded
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | There were no exceedances of the 12 samples for copper in tissue for all 4 stations. Tissue concentration measured from 0.76 to 3.13 ppm (Keeling, S. 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | US Fish and Wildlife Biological Effects value for copper is 15 ppm.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Four sites were sampled on Morro Bay: 427.0, 428.5, 429.0, and 429.2.
Temporal Representation: | Sampling occurred from 5-30-1980 to 1-20-1993.
Environmental Conditions: |
QAPP Information: | State Mussel Watch Program Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 91
Pollutant: | Copper
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Estuarine Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | None of the five samples taken at the 5 stations exceeded any of the CTR dissolved copper criteria in the water column. Dissolved copper concentrations ranged from 0.815 to 0.262 μg/L (Keeling, S. 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Waters shall not contain suspended material in concentrations that cause nuisance or adversely affect beneficial uses. Waters shall not contain settleable material in concentrations that result in deposition of material that causes nuisance or adversely affects beneficial uses. The CTR criteria for the dissolved fraction of copper is applicable for the protection of aquatic life.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | CTR Saltwater acute 4.8 μg/L Criterion Maximum Concentration (CMC) and saltwater chronic 3.1 μg/L Criterion Continuous Concentration (CCC) criteria.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Water was sampled from five (5) separate locations representing the back, middle and front of the Bay including the inflows from the mouth Chorro and the mouth of Los Osos creeks that feed into the Bay. The stations are: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: |
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):

DECISION ID | 5686
Pollutant: | Lead
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.5 of the Listing Policy. Under section 3.5 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. There is no criteria or guideline available for lead in tissue that meets the requirements of the Listing Policy. 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. 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.No exceedances were recorded because there is no criteria or guideline available for lead in tissue that meets the requirements of the Listing Policy. 4.Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because there is no water quality objective, criteria or guideline for lead in tissue that meets the requirements of section 6.1.3 of the Listing Policy and it cannot be determined if applicable water quality standards are exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 5686

LOE ID: | 98
Pollutant: | Lead
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Not Recorded
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | No exceedances were recorded because there is no criteria or guideline available for lead in tissue that meets the requirements of the Listing Policy (Keeling, S. 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | There is no criteria or guideline available for lead in tissue that meets the requirements of the Listing Policy.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | There were five sampling sites samples throughout Morro Bay. Locations represented the back, middle, and front of the Bay including inflows from Chorro and Los Osos Creeks.
Temporal Representation: | Samples were taken on April 29 and May 4-5, 2002.
Environmental Conditions: |
QAPP Information: | State Mussel Watch Program Quality Assurance Plan.
QAPP Information Reference(s):

DECISION ID | 4769
Pollutant: | Mercury
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.5 of the Listing Policy. Under section 3.5 a single line of evidence is necessary to assess delisting status. Two lines of evidence are available in the administrative record to assess this pollutant. Mercury is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy. The CTR criteria for the dissolved fraction of selected metals are applicable for the protection of aquatic life but there is no CTR criterion for dissolved mercury in the saltwater column. However, OEHHA screening values are applicable for consumption of aquatic organisms. 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 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. None of the 12 tissue samples exceeded the OEHHA screening value and none of the five water samples taken were in exceedance because there are no guidelines for dissolved mercury in the saltwater column that meet the requirements of the Listing Policy. This does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards for the pollutant are not exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4769

LOE ID: | 89
Pollutant: | Mercury
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | None of the 12 samples exceeded the OEHHA screening value at the 4 sampling stations (Keeling, 2003). This is one of five metals originally included in the 1996-303(d) metals listing. The listing was originally based on exceedances of Median International Standards (MIS) and Elevated Data Levels (EDL) guidelines for State Mussel Watch tissue data. The MIS and EDL guidelines do not meet the requirements of the Listing Policy. Two samples out of eight were found to be above the EDL 85 values (0.06 ppm) with concentrations of 0.136 ppm and 0.061 ppm wet weight on 1/26/1987 and 1/20/1993 respectively. Both samples were taken at site 429.2.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | OEHHA screening values of 0.3 ppm.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Four sites were sampled on Morro Bay: 427.0, 428.5, 429.0, and 429.2.
Temporal Representation: | Sampling occurred from 5-30-1980 to 1-20-1993.
Environmental Conditions: |
QAPP Information: | State Mussel Watch Program Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 90
Pollutant: | Mercury
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Estuarine Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | None of the five samples taken in Morro Bay exceeded because there are no guidelines for dissolved mercury in the saltwater column that meet the requirements of the Listing Policy (Keeling, 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Waters shall not contain suspended material in concentrations that cause nuisance or adversely affect beneficial uses. Waters shall not contain settleable material in concentrations that result in deposition of material that causes nuisance or adversely affects beneficial uses.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | There are no acute or chronic criteria for dissolved mercury in saltwater that meets the requirements of the Listing Policy.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Water was sampled from five (5) separate locations meant to represent the back, middle and front of the Bay and were also meant to represent the flow from the two creeks that feed the Bay (sites were Front Bay, Middle Bay, Back Bay, Mouth Chorro and Mouth Los Osos. The stations are: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: |
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):

DECISION ID | 4645
Pollutant: | Nickel
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. One line of evidence pertains to Nickel concentrations in the saltwater column, and the other pertains to Nickel concentrations in tissue. An insufficient number of samples exceed the CTR chronic-CCC criteria and there is no applicable guidelines to assess Nickel in tissue. 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 five samples exceeded the CTR chronic criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4.Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards for the pollutant are not exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4645

LOE ID: | 95
Pollutant: | Nickel
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Not Recorded
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | No standards exist. Tissue values ranged from 0.6 to 1.08 ppm for all 12 samples at all 4 sites (Keeling, S. 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: | There is no criteria or guideline for Nickel in tissue that meets the requirement of the Listing Policy.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Four sites were sampled on Morro Bay: 427.0, 428.5, 429.0, and 429.2.
Temporal Representation: | Sampling occurred from 5-30-1980 to 1-20-1993.
Environmental Conditions: |
QAPP Information: | State Mussel Watch Quality Assurance Plan.
QAPP Information Reference(s):
LOE ID: | 94
Pollutant: | Nickel
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Estuarine Habitat
Number of Samples: | 5
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | One of five samples (at the mouth of Chorro Creek - 11.300 ug/l) exceeded the CTR-chronic CCC guideline and no sample exceeded the Acute CMC-CTR guideline concentration (Keeling, S. 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Waters shall not contain suspended material in concentrations that cause nuisance or adversely affect beneficial uses. Waters shall not contain settleable material in concentrations that result in deposition of material that causes nuisance or adversely affects beneficial uses. Water quality objective in marine environment - total concentration 2 ppb.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | CTR dissolved Nickel Saltwater acute is 74 ug/l (CMC) and saltwater chronic is 8.2 ug/l(CCC) criteria applicable for the protection of aquatic life in saltwater.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Water was sampled from five (5) separate locations representing the back, middle and front of the Bay including inflows from the mouth of the Chorro and the mouth of Los Osos creeks that that feed the Bay. The stations are: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: |
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):

DECISION ID | 4646
Pollutant: | Vanadium (fume or dust)
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. It is not possible to determine exceedances of any standard because there are no guidelines for dissolved Vanadium in the saltwater column for the protection of aquatic life or any applicable guideline for Vanadium in tissue that meets the requirements of the Listing Policy. 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.No samples exceeded any water quality standard and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4.Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because there is no water quality objective, criteria or guideline that meets the requirements of section 6.1.3 of the Listing Policy and it cannot be determined if applicable water quality standards are exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4646

LOE ID: | 96
Pollutant: | Vanadium (fume or dust)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Estuarine Habitat
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | None of the five samples taken were found to exceed because there is no criterion or guideline for dissolved Vanadium in the saltwater column for the protection of aquatic life that meets the requirements of the Listing Policy (Keeling, S. 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Waters shall not contain suspended material in concentrations that cause nuisance or adversely affect beneficial uses. Waters shall not contain settleable material in concentrations that result in deposition of material that causes nuisance or adversely affects beneficial uses.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Water was sampled from five (5) separate locations representing the back, middle and front of the Bay including inflow from the mouth Chorro and mouth Los Osos creeks that feed into the Bay. The stations are: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: |
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):

DECISION ID | 4647
Pollutant: | Zinc
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples in the water column exceed any of the CTR criteria for dissolved Zinc for the protection of aquatic life. In addition there is no criteria or guideline for Zinc in tissue that meets the requirements of the Listing Policy. 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.No samples exceeded any of the CTR criteria for the protection of aquatic life in the saltwater column. In addition, it was not possible to evaluate zinc in tissue samples because there is no guideline that meets the requirement of the Listing. This does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4.Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards for the pollutant are not exceeded.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4647

LOE ID: | 97
Pollutant: | Zinc
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Estuarine Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | None of the five samples taken in Morro Bay exceeded any of the dissolved zinc acute or chronic criteria (Keeling, S. 2003).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | Waters shall not contain suspended material in concentrations that cause nuisance or adversely affect beneficial uses. Waters shall not contain settleable material in concentrations that result in deposition of material that causes nuisance or adversely affects beneficial uses. Water quality objective in marine environment - total concentration 20 ppb.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | Dissolved Zinc CTR Saltwater acute (CMC) criterion is 90 ug/L and saltwater chronic (CCC) criterion is 81 ug/L for the protection of aquatic life in the water column.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Water was sampled from five (5) separate locations representing the back, middle and front of the Bay including inflows from the mouth of Chorro and the mouth of Los Osos creeks that feed the Bay. The stations are: Back Bay, Mouth Los Osos, Mouth Chorro, Middle Bay and Front Bay.
Temporal Representation: | Water was sampled on March 8, 2001.
Environmental Conditions: |
QAPP Information: | Battelle Laboratory Quality Assurance Plan.
QAPP Information Reference(s):

DECISION ID | 4865
Pollutant: | Oxygen, Dissolved
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Sources: | Source Unknown
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. A large number of samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Two hundred and thirty-one of 283 samples exceeded the water quality objective and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4865

LOE ID: | 80
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Adverse Biological Responses
Matrix: | -N/A
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 283
Number of Exceedances: | 231
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Regional Board staff is proposing that Morro Bay be listed as impaired for dissolved oxygen. The impairment is evidenced by depressed levels of dissolved oxygen measured during pre-dawn and 24-hour sampling periods. Two Hundred and thirty one data points (of a total of 283 data points) collected between 1997 and 2002 fell below the water quality objective of 7.0 mg/L (CCRWQCB, 2004o). Depressed oxygen levels were found at all sampling locations except for EEL. There were 231 out of 283 samples that exceeded the COLD dissolved oxygen water quality objective.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | MAR = Marine Habitat
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | COLD Dissolved Oxygen = 7.0 mg/L.
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Morro Bay Estuary (Calwater watershed no. 31023012), San Luis Obispo County. Samples were collected at 8 locations throughout the bay: ATP, SPM, Lo2, PSP, EEL, Ch1, CSI, and SHI.
Temporal Representation: | Single measurements were taken in the Morro Bay estuary using a hand-held meter. Measurements were taken during pre-dawn conditions from 4/17/1997 through 12/132002.
Environmental Conditions: | Samples were primarily taken during pre-dawn conditions, when dissolved oxygen levels are expected to be lowest.
QAPP Information: | Samples were taken according to the Morro Bay Volunteer Monitoring Program protocols for pre-dawn sampling in the Morro Bay National Estuary Programs Quality Assurance Program Plan. The Morro Bay Volunteer Monitoring Program staff has monthly correspondence with volunteers regarding data review, meter operation, and safety. Volunteer monitors collect dissolved oxygen data according to the Morro Bay National Estuary Programs Quality Assurance Program Plan.
QAPP Information Reference(s):

DECISION ID | 4171
Pollutant: | Pathogens
Final Listing Decision: | List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (being addressed by USEPA approved TMDL)(2006)
Revision Status | Original
Sources: | Natural Sources | Nonpoint Source | Range Grazing-Upland | Septage Disposal | Urban Runoff/Storm Sewers
TMDL Name: | Morro Bay Pathogens
TMDL Project Code: | 22
Date TMDL Approved by USEPA: | 01/20/2004
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for listing under section 2.2 of the Listing Policy. Under this section of the Policy, a minimum of one line of evidence is needed to assess listing status. The Morro Bay Pathogens TMDL was approved by RWQCB on May 16, 2003 and subsequently approved by USEPA on January 20, 2004. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination in the Water Quality Limited Segments Being Addressed portion of the section 303(d) list.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information for this recommendation, SWRCB staff conclude that the water body should be placed in the Water Quality Limited Segments Being Addressed category of the section 303(d) list because a TMDL has been approved by USEPA and an implementation plan has been approved.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4171

LOE ID: | 78
Pollutant: | Pathogens
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Not Recorded
Beneficial Use: | Water Contact Recreation
Number of Samples: |
Number of Exceedances: |
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: |
Temporal Representation: |
Environmental Conditions: |
QAPP Information: | QA Info Missing
QAPP Information Reference(s):

DECISION ID | 4170
Pollutant: | Sedimentation/Siltation
Final Listing Decision: | List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (being addressed by USEPA approved TMDL)(2006)
Revision Status | Original
Sources: | Agriculture | Channel Erosion | Channelization | Construction/Land Development | Irrigated Crop Production | Resource Extraction
TMDL Name: | Morro Bay Sediment
TMDL Project Code: | 242
Date TMDL Approved by USEPA: | 01/20/2004
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for listing under section 2.2 of the Listing Policy. Under this section of the Policy, a minimum of one line of evidence is needed to assess listing status. The Morro Bay Sediment TMDL was approved by RWQCB on May 16, 2003 and subsequently approved by USEPA on January 20, 2004. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination in the Water Quality Limited Segments Being Addressed portion of the section 303(d) list.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | After review of the available data and information for this recommendation, SWRCB staff conclude that the water body should be placed in the Water Quality Limited Segments Being Addressed category of the section 303(d) list because a TMDL has been approved by USEPA and an implementation plan has been approved.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4170

LOE ID: | 77
Pollutant: | Sedimentation/Siltation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Not Recorded
Beneficial Use: | Estuarine Habitat
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: |
Temporal Representation: |
Environmental Conditions: |
QAPP Information: | QA Info Missing
QAPP Information Reference(s):