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DECISION ID |
17212 |
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| 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 |
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| 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.
Two 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 Arroyo Seco Reach 1 were very poor in October of 2003 and very poor in October of 2004 indicating impairment of benthic community structure. This impairment is associated with impairment for trash.
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. |
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| 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. |
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| SWRCB Board Decision / Staff Recommendation: |
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| USEPA Decision: |
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| LOE ID: |
30223 |
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| Pollutant: |
Benthic-Macroinvertebrate Bioassessments |
| LOE Subgroup: |
Population/Community Degradation |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Non-Contact Recreation |
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| Number of Samples: |
0 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
Benthic macroinvertebrate surveys |
| Data Used to Assess Water Quality: |
The IBI scores at this site ranked in the very poor range (11 in 2003 and 9 in 2004). |
| Data Reference: |
Los Angeles County 1994-2005 Integrated Receiving Water Impacts Report. Section 5, Los Angeles River Watershed Management Area, pp5.1 - 5.40 |
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| Water Quality Objective/Criterion: |
Los Angeles RWQCB Basin Plan Objectives for Toxicity which states 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, analyses of species diversity, population density, growth anomalies, bioassays of appropriate duration or other appropraite methods as specified by the State or Regional Board. |
| Objective/Criterion Reference: |
Water Quality Control Plan Los Angeles Region R4 Basin Plan |
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Basin Plan Amendments to the Water Quality Control Plan Los Angeles Region R4 Basin Plan as of 02/02/2009 |
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| 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 according to very good (80-56), good (41-55), fair (27-40), poor (14-26) and very poor (0-13) habitat conditions. Sites with scores below 26 are considered to have impaired conditions. |
| Guideline Reference: |
A Quantitative Tool for Assessing the Integrity of Southern Coastal California Streams. Environmental Management Vol. 35, No. 4, pp. 493-504. |
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Los Angeles County 1994-2005 Integrated Receiving Water Impacts Report. Section 3, Methods, pp3.1 - 3.28 |
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Los Angeles County 1994-2005 Integrated Receiving Water Impacts Report. Section 5, Los Angeles River Watershed Management Area, pp5.1 - 5.40 |
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| Spatial Representation: |
One site in the Arroyo Seco was sampled, Arroyo Seco and I-134, at N 34º 08.686 W 118º 09.987 |
| Temporal Representation: |
Sites were sampled in October of 2003 and October of 2004. |
| Environmental Conditions: |
Benthic macroinvertebrate populations and IBI scores may also be affected by a wide range of anthropogenic stressors. |
| QAPP Information: |
Data was collected in compliance with California Stream Bioassessment Procedure. |
| QAPP Information Reference(s): |
California Stream Bioassessment Procedure (Protocol Brief for Biological and Physical/Habitat Assessment in Wadeable Streams) California Department of Fish and Game Water Pollution Control Laboratory Aquatic Bioassessment Laboratory Revision Date - December, 2003 |
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Los Angeles County 1994-2005 Integrated Receiving Water Impacts Report. Section 3, Methods, pp3.1 - 3.28 |
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| LOE ID: |
4028 |
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| Pollutant: |
Trash |
| LOE Subgroup: |
Visual |
| Matrix: |
Not Specified |
| Fraction: |
Not Recorded |
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| Beneficial Use: |
Non-Contact Recreation |
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| Number of Samples: |
0 |
| Number of Exceedances: |
0 |
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| 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) |
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| Water Quality Objective/Criterion: |
Unspecified |
| Objective/Criterion Reference: |
Placeholder reference pre-2006 303(d) |
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| Evaluation Guideline: |
Unspecified |
| Guideline Reference: |
Placeholder reference pre-2006 303(d) |
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| Spatial Representation: |
Unspecified |
| Temporal Representation: |
Unspecified |
| Environmental Conditions: |
Unspecified |
| QAPP Information: |
Unspecified |
| QAPP Information Reference(s): |
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DECISION ID |
7181 |
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| 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 |
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| Weight of Evidence: |
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. |
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| RWQCB Board Decision / Staff 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. |
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| SWRCB Board Decision / Staff Recommendation: |
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| USEPA Decision: |
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Lines of Evidence (LOEs) for Decision ID 7181 |
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| LOE ID: |
28085 |
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| Pollutant: |
Trash |
| LOE Subgroup: |
Narrative Description Data |
| Matrix: |
Not Specified |
| Fraction: |
None |
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| Beneficial Use: |
Non-Contact Recreation |
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| Number of Samples: |
0 |
| Number of Exceedances: |
0 |
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| 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: |
Basin Plan Amendments to the Water Quality Control Plan Los Angeles Region R4 Basin Plan as of 02/02/2009 |
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| Water Quality Objective/Criterion: |
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| Objective/Criterion Reference: |
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| Evaluation Guideline: |
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| Guideline Reference: |
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| Spatial Representation: |
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| Temporal Representation: |
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| Environmental Conditions: |
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| QAPP Information: |
QA information unavailable. |
| QAPP Information Reference(s): |
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| LOE ID: |
4028 |
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| Pollutant: |
Trash |
| LOE Subgroup: |
Visual |
| Matrix: |
Not Specified |
| Fraction: |
Not Recorded |
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| Beneficial Use: |
Non-Contact Recreation |
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| Number of Samples: |
0 |
| Number of Exceedances: |
0 |
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| 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) |
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| Water Quality Objective/Criterion: |
Unspecified |
| Objective/Criterion Reference: |
Placeholder reference pre-2006 303(d) |
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| Evaluation Guideline: |
Unspecified |
| Guideline Reference: |
Placeholder reference pre-2006 303(d) |
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| Spatial Representation: |
Unspecified |
| Temporal Representation: |
Unspecified |
| Environmental Conditions: |
Unspecified |
| QAPP Information: |
Unspecified |
| QAPP Information Reference(s): |