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

Supporting Information

Regional Board 4 - Los Angeles Region

Water Body Name: Triunfo Canyon Creek Reach 2
Water Body ID: CAR4042400019990202082235
Water Body Type: River & Stream
 
DECISION ID
17211
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: Nonpoint Source | Point Source
Expected TMDL Completion Date: 2021
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for the section 303(d) list under section 3.9 of the Listing Policy. Under section 3.9, waters are listed when a bioassessment shows diminished numbers of species or other metrics (compared to a reference site) and it is associated with another pollutant.

Six lines of evidence are available in the administrative record to assess this pollutant. Benthic macroinvertebrates as measured by Southern California IBI (index of biological integrity) in Triunfo Creek Reach 2 were very poor in the spring and very poor in the fall of 2005. indicating impairment of benthic community structure. This impairment is associated with impairment for Lead, Mercury, and Sedimentation/Siltation.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification to place the 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. There is at least one bioassessment sample (Index of Biological Integrity score) to satisfy Section 3.9
4. The impairment is associated with another pollutant in the waterbody to satisfy Section 3.9
5. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be added to the section 303(d) list because applicable water quality standards are not being attained.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 17211
 
LOE ID: 4254
 
Pollutant: Sedimentation/Siltation
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)
 
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):

 
LOE ID: 4252
 
Pollutant: Lead
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)
 
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):

 
LOE ID: 4253
 
Pollutant: Mercury
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: 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)
 
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):