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

Supporting Information

Regional Board 4 - Los Angeles Region

Water Body Name: Arroyo Seco Reach 2 (West Holly Ave to Devils Gate Dam)
Water Body ID: CAR4051501019990202133129
Water Body Type: River & Stream
 
DECISION ID
7188
Region 4     
Arroyo Seco Reach 2 (West Holly Ave to Devils Gate Dam)
 
Pollutant: Trash
Final Listing Decision: List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2006)
Revision Status Revised
Sources: Nonpoint Source | Surface Runoff | Urban Runoff/Storm Sewers
TMDL Name: Los Angeles River Trash (12)
TMDL Project Code: 365
Date TMDL Approved by USEPA: 07/24/2008
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal on the section 303(d) list under sections 2.2 of the Listing Policy. Under 2.2 of the Policy, a minimum of one line of evidence is needed to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list. There is sufficient justification to place it in the Being Addressed portion of the 303(d) list because a TMDL has been completed and adopted by the Los Angeles RWQCB and approved by USEPA, and is expected to result in attainment of the standard.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the Water Quality Limited Segments Being Addressed category of the section 303(d) list because a TMDL has been approved by USEPA, and applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
 
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 7188, Trash
Region 4     
Arroyo Seco Reach 2 (West Holly Ave to Devils Gate Dam)
 
LOE ID: 28086
 
Pollutant: Trash
LOE Subgroup: Narrative Description Data
Matrix: Not Specified
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: A TMDL has been approved for this water segment-pollutant combination. The Trash TMDL for the Los Angeles River Watershed was adopted by the Los Angeles RWQCB on August 09, 2007 and subsequently approved by USEPA. The TMDL was been integrated into the Basin Plan as Attachment A of Regional Board Resolution No. 2007-012.
Data Reference: Water Quality Control Plan Los Angeles Region R4 Basin Plan
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion:
Objective/Criterion Reference:
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation:
Temporal Representation:
Environmental Conditions:
QAPP Information: QA information unavailable.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 7188, Trash
Region 4     
Arroyo Seco Reach 2 (West Holly Ave to Devils Gate Dam)
 
LOE ID: 4030
 
Pollutant: Trash
LOE Subgroup: Visual
Matrix: Not Specified
Fraction: Not Recorded
 
Beneficial Use: Non-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 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
4183
Region 4     
Arroyo Seco Reach 2 (West Holly Ave to Devils Gate Dam)
 
Pollutant: Excess Algal Growth
Final Listing Decision: Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Delist from 303(d) list (TMDL required list)(2006)
Revision Status Original
Reason for Delisting: Flaws in original listing
Impairment from Pollutant or Pollution: Pollution
 
Regional Board Conclusion: The Los Angeles River Nitrogen TMDL was approved by RWQCB on August 19, 2003 and subsequently approved by USEPA on March 18, 2004. This TMDL will address this water body condition. Qualitative information on excess algal growth alone is not sufficient to support placement on the section 303(d) list (Listing Policy section 3.7). It is expected that this TMDL will address the pollutant(s) contributing to or causing this condition.

After review of the available data and information for this recommendation, SWRCB staff conclude that the water body should not be placed in the Water Quality Limited Segments category of the section 303(d) list because excess algal growth is not a pollutant and it is uncertain if the growth data are backed by pollutant data showing exceedances of water quality standards.
 
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 4183, Excess Algal Growth
Region 4     
Arroyo Seco Reach 2 (West Holly Ave to Devils Gate Dam)
 
LOE ID: 2488
 
Pollutant: Excess Algal Growth
LOE Subgroup: Narrative Description Data
Matrix: Not Specified
Fraction: None
 
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: A TMDL and implementation plan has been approved for this water segment-pollutant combination. The Los Angeles River Nitrogen TMDL was approved by RWQCB on August 19, 2003 and subsequently approved by USEPA on March 18, 2004. This TMDL will address this water body condition.
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
7183
Region 4     
Arroyo Seco Reach 2 (West Holly Ave to Devils Gate Dam)
 
Pollutant: Coliform Bacteria
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: 2009
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 7183, Coliform Bacteria
Region 4     
Arroyo Seco Reach 2 (West Holly Ave to Devils Gate Dam)
 
LOE ID: 4029
 
Pollutant: Coliform Bacteria
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 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):