Final California 2010 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 4 - Los Angeles Region

Water Body Name: Topanga Canyon Creek
Water Body ID: CAR4041100019980918145717
Water Body Type: River & Stream
 
DECISION ID
6730
Region 4     
Topanga Canyon Creek
 
Pollutant: Sulfates
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
 
Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. An insufficient total number of samples were taken and an insufficient number of samples exceed the MCL guideline for Sulfate.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient 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. Four of four samples exceeded the MCL guideline. More data is needed to determine if the water quality standard is exceeded.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: The decision has not changed.
 
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.
 
USEPA Action (if applicable):
 
 
Line of Evidence (LOE) for Decision ID 6730, Sulfates
Region 4     
Topanga Canyon Creek
 
LOE ID: 2240
 
Pollutant: Sulfates
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: There was a total of four samples with all four exceeding the objectives (SWAMP, 2004).
Data Reference: Placeholder reference 2006 303(d)
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: CCR- Title 22 Table 64449-B Secondary Maximum Contaminant Levels of 250 mg/l for Sulfate.
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Two stations at Topanga Canyon Creek Middle: 34.06499 -118.58679 an at Topanga Canyon Creek Upper: 34.08991 -118.60487.
Temporal Representation: Samples were collected March 2003 through March 2004.
Environmental Conditions: Los Angeles County Coastal Streams: 404.11.
QAPP Information: SWAMP Quality Assurance Plan.
QAPP Information Reference(s):
 
 
DECISION ID
7094
Region 4     
Topanga Canyon Creek
 
Pollutant: Lead
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: Nonpoint Source
Expected TMDL Completion Date: 2019
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: 303(d) listing decisions made prior to 2006 were not held in an assessment database. The Regional Boards will update this decision when new data and information become available and are assessed.
 
Regional Board Decision Recommendation: The decision has not changed.
 
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.
 
USEPA Action (if applicable): USEPA approved the listing of this water body as a water quality limited segment requiring a TMDL for this pollutant.
 
 
Line of Evidence (LOE) for Decision ID 7094, Lead
Region 4     
Topanga Canyon Creek
 
LOE ID: 4173
 
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)
 
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):