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

Supporting Information

Regional Board 4 - Los Angeles Region

Water Body Name:	Trancas Canyon Creek
Water Body ID:	CAR4043700020050623115219
Water Body Type:	River & Stream


DECISION ID	34497	Region 4
Trancas Canyon Creek

Pollutant:	Chloride
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)(2012)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Staff 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. A sufficient total number of samples were taken but an insufficient number of samples exceed the MCL guideline for Chloride. 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. Two of five 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 Staff Decision Recommendation:	This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current cycle. The decision has not changed.

Line of Evidence (LOE) for Decision ID 34497, Chloride	Region 4
Trancas Canyon Creek

LOE ID:

2274

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

There was a total of five samples with two exceeding the objective (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 Chloride.

Objective/Criterion Reference:

Placeholder reference 2006 303(d)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Two stations at Trancas Canyon Creek Lower: 34.03036 -118.84181 and at Trancas Canyon Creek Upper: 34.04347 -118.84541.

Temporal Representation:

Samples were collected March 2003 through March 2004.

Environmental Conditions:

Los Angeles County Coastal Streams: 404.37.

QAPP Information:

SWAMP Quality Assurance Plan.

QAPP Information Reference(s):


DECISION ID	36161	Region 4
Trancas 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)(2012)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Staff 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. A sufficient total number of samples were taken but 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. Two of five 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 Staff Decision Recommendation:	This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current cycle. The decision has not changed.

Line of Evidence (LOE) for Decision ID 36161, Sulfates	Region 4
Trancas Canyon Creek

LOE ID:

2275

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

There was a total of five samples with two exceeding the objective (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 Trancas Canyon Creek Lower: 34.03036 -118.84181and at Trancas Canyon Creek Upper: 34.04347 -118.84541.

Temporal Representation:

Samples were collected March 2003 through March 2004.

Environmental Conditions:

Los Angeles County Coastal Streams: 404.37.

QAPP Information:

SWAMP Quality Assurance Plan.

QAPP Information Reference(s):