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

Supporting Information

Regional Board 9 - San Diego Region

Water Body Name: Stone Creek (San Diego County)
Water Body ID: CAR9022200020110820082651
Water Body Type: River & Stream
 
DECISION ID
97668
Region 9     
Stone Creek (San Diego County)
 
Pollutant: Benthic Community Effects
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollution
 
Regional Board Conclusion: Benthic Community Effects is being considered for placement on the CWA section 303(d) List under sections 3.9 and 3.1 of the Listing Policy. Under section 3.9, an additional line of evidence associating Benthic Community Effects with a water or sediment concentration of pollutant(s) is necessary to assess listing status.

Based on the readily available data and information, the weight of evidence provides sufficient justification for not 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. Pursuant to section 3.9 of the Listing Policy, the water does not exhibit significant degradation in biological populations and/or communities as compared to reference site(s) using the California Stream Condition Index.
4. Pursuant to section 3.9 of the Listing Policy, the water segment does not have associated pollutant(s) samples that exceed water quality objectives.
5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not being met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 97668, Benthic Community Effects
Region 9     
Stone Creek (San Diego County)
 
LOE ID: 79477
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: The CSCI scores for this site are above the 0.79 threshold, and therefore the site is not exceeding the water quality objective for the aquatic life beneficial use.
Data Reference: RWB9 Status Sampling 2007 and 2008
  Region 9 CSCI Scores & Water Body Information
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant or animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analysis of species diversity, population density, growth anomalies, bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board. Region 9 Basin Plan.
Objective/Criterion Reference: Water Quality Control Plan for the San Diego Basin
 
Evaluation Guideline: The California Stream Condition Index (CSCI) is a biological scoring tool that helps aquatic resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score is calculated by comparing the expected condition with actual (observed) results (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: Bioassessment in complex environments: designing an index for consistent meaning in different settings
 
Spatial Representation: Samples were collected at the following station: 902SMSTN1-Stone Creek 1.
Temporal Representation: Surveys done June 5, 2007 and May 6, 2008.
Environmental Conditions:
QAPP Information: Data collected following SWAMP QA protocols for the RWB9 Status Sampling 2007 and 2008 water quality monitoring project.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 97668, Benthic Community Effects
Region 9     
Stone Creek (San Diego County)
 
LOE ID: 76948
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: All of the IBI scores for this water body were above 40 which indicates that this water body is not considered to have impaired conditions.
Data Reference: RWB9 Status Sampling 2007 and 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: Water Quality Control Plan for the San Diego Basin
 
Evaluation Guideline: The IBI is a multi-metric assessment that employs biological metrics that respond to a habitat or water quality impairment. Each of the biological metrics measured at a site are converted to an IBI score then summed. These cumulative scores are then ranked. For the Southern California IBI, sites with scores below 40 are considered to have impaired conditions.
Guideline Reference: A Quantitative Tool for Assessing the Integrity of Southern Coastal California Streams. Environmental Management. Volume 35, number 1 (2005): pp. 1-13
 
Spatial Representation: Samples were collected at the following station: 902SMSTN1-Stone Creek 1.
Temporal Representation: Surveys done June 5, 2007 and May 6, 2008.
Environmental Conditions:
QAPP Information: Data collected following SWAMP QA protocols for the RWB9 Status Sampling 2007 and 2008 water quality monitoring project.
QAPP Information Reference(s):