Draft California 2016 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 2 - San Francisco Bay Region

Water Body Name: Napa River
Water Body ID: CAR2065001019980928164417
Water Body Type: River & Stream
 
DECISION ID
34017
Region 2     
Napa River
 
Pollutant: Nutrients
Final Listing Decision: Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2012)
Revision Status Revised
Reason for Delisting: Delisting due to spatial change or other CalWQA administrative reason
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This is a de-listing because the Napa River was split into 3 waterbodies, and the listing was transferred to the appropriate portions of the new waterbodies.
 
Regional Board Decision Recommendation: This is a de-listing because the Napa River was split into 3 waterbodies, and the listing was transferred to the appropriate portions of the new waterbodies.
 
 
Line of Evidence (LOE) for Decision ID 34017, Nutrients
Region 2     
Napa River
 
LOE ID: 3768
 
Pollutant: Nutrients
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference pre-2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Unspecified
Objective/Criterion Reference: Placeholder reference pre-2006 303(d)
 
Evaluation Guideline: Unspecified
Guideline Reference: Placeholder reference pre-2006 303(d)
 
Spatial Representation: Unspecified
Temporal Representation: Unspecified
Environmental Conditions: Unspecified
QAPP Information: Unspecified
QAPP Information Reference(s):
 
 
DECISION ID
35007
Region 2     
Napa River
 
Pollutant: Pathogens
Final Listing Decision: Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (being addressed by USEPA approved TMDL)(2012)
Revision Status Revised
Reason for Delisting: Delisting due to spatial change or other CalWQA administrative reason
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This is a de-listing because the Napa River was split into 3 waterbodies, and the listing was transferred to the appropriate portions of the new waterbodies.
 
Regional Board Decision Recommendation: This is a de-listing because the Napa River was split into 3 waterbodies, and the listing was transferred to the appropriate portions of the new waterbodies.
 
 
Line of Evidence (LOE) for Decision ID 35007, Pathogens
Region 2     
Napa River
 
LOE ID: 1824
 
Pollutant: Pathogens
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference 2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion:
Objective/Criterion Reference:
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation:
Temporal Representation:
Environmental Conditions:
QAPP Information: QA Info Missing
QAPP Information Reference(s):
 
 
DECISION ID
44582
Region 2     
Napa River
 
Pollutant: Sedimentation/Siltation
Final Listing Decision: Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2012)
Revision Status Revised
Reason for Delisting: Delisting due to spatial change or other CalWQA administrative reason
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This is a de-listing because the Napa River was split into 3 waterbodies, and the listing was transferred to the appropriate portion of the new waterbodies.
 
Regional Board Decision Recommendation: This is a de-listing because the Napa River was split into 3 waterbodies, and the listing was transferred to the appropriate portions of the new waterbodies.
 
 
Line of Evidence (LOE) for Decision ID 44582, Sedimentation/Siltation
Region 2     
Napa River
 
LOE ID: 3769
 
Pollutant: Sedimentation/Siltation
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference pre-2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Unspecified
Objective/Criterion Reference: Placeholder reference pre-2006 303(d)
 
Evaluation Guideline: Unspecified
Guideline Reference: Placeholder reference pre-2006 303(d)
 
Spatial Representation: Unspecified
Temporal Representation: Unspecified
Environmental Conditions: Unspecified
QAPP Information: Unspecified
QAPP Information Reference(s):
 
 
DECISION ID
67406
Region 2     
Napa River
 
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 is being considered for placement on the CWA section 303(d) List under sections 3.9 of the Listing Policy. Under section 3.9, an additional line of evidence associating the Benthic Community Effects with a water or sediment concentration of pollutants is necessary to assess listing status. One line of evidence is available in the administrative record. The six CSCI scores for this water body are all above 0.92.
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 water 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. The six CSCI scores for this water body are all above 0.92. Additionally, this water body passed several screening criteria and was identified as a reference water body for the purposes of developing the CSCI. The State Water Board has redefined the Integrated Reporting categories in order to make them more reflective of actual water quality conditions in the State. This revision allows for the inclusion of minimally disturbed data reference sites that were identified in the development of the California Stream Condition Index (CSCI) tool into Category 1. Reference sites are the core of the State?s statewide biological and habitat assessment program and set the benchmark for biological conditions expected when human activity in the landscape is absent or minimal. Unless there is any additional data showing that beneficial uses in a water body are not being supported, these reference water bodies along with any other bioassessment data sets showing a score of 0.92 or higher will be placed in Category 1 (all core beneficial uses are supported).
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

The Regional Board does not want to include this water body in Category 1 at this time.
 
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.
 
 
Line of Evidence (LOE) for Decision ID 67406, Benthic Community Effects
Region 2     
Napa River
 
LOE ID: 96013
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: The CSCI scores for these sites are 1.034604, 1.066129, 0.983922, 1.244608, 1.23922, and 1.134949 and are therefore meeting the water quality objective for this water body. This water body passed several screening criteria and was identified as a reference water body for the purposes of developing the CSCI. Reference sites where human disturbance is absent or minimal are used to set benchmark expectations for healthy streams. A large set of nearly 600 reference sites representing the broad diversity of natural stream types found across California was used to develop the CSCI.
Data Reference: RWB2 Reference Study Monitoring 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are lethal to or that produce significant alterations in population or community ecology or receiving water biota. In addition, the health and life history characteristics of aquatic organisms in waters affected by controllable water quality factors shall not differ significantly from those for the same waters in areas unaffected by controllable water quality factors.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) San Francisco Bay Basin (Region 2)
 
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 (Rhen, 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: The California Stream Condition Index (CSCI): A New Statewide Biological Scoring Tool for Assessing the Health of Freshwater Streams.
 
Spatial Representation: Sampling was done at to following stations: 206BEA035, 206CON130, 206DRY040, 206DRY060, 206DRY100, 206TUL120
Temporal Representation: Sampling was done:
4/25/2001
5/3/2000
4/23/2001
4/23/2001
5/3/2000
6/13/2011
Environmental Conditions:
QAPP Information: Data collected following SWAMP QA protocols.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan