| Water Body Name: | Arroyo Seco Reach 1 (LA River to West Holly Ave.) |
| Water Body ID: | CAR4051501019990202132906 |
| Water Body Type: | River & Stream |
DECISION ID |
17212 |
Region 4 |
Arroyo Seco Reach 1 (LA River to West Holly Ave.) |
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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: | Source Unknown |
| Expected TMDL Completion Date: | 2021 |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | Regional Board Conclusion:
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. One line of evidence is 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. 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 in Category 4C of 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. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met. State Board Review and Conclusion: State Water Board staff used a situation-specific weight of evidence approach to evaluate the Los Angeles Water Board benthic macroinvertebratebioassessment listing. State Water Board staff determined that it is necessary to include these listings because additional data analyses and multiple line of evidence show that benthic macroinvertebrate populations are impacted by a wide range of stressors. Using this approach staff followed a three-step process for evaluation of all available water quality data including the chemistry and bioassessment data. In the first step, staff reviewed the Los Angeles Water Board data evaluation for bioassessment listing. In the second step, staff reviewed all other available bioassessment data because State Water Board staff learned that some data had not been considered for this listing decision by the Regional Water Board. In step 3 staff reviewed the chemistry water quality data available for coliform bacteria, trash, cyanide, pH, dissoved oxygen, nitrite, aluminum, lead, copper, zinc, and diazinon to determine the water quality condition in this water body segment. In step 1 and 2, State Water Board staff evaluated the bioassessment data using the Southern California index of biological integrity (IBI). Staff reviewed the line of evidence prepared by the Los Angeles Water Board and additional bioassessment data. Benthic macroinvertebrate as measured by Southern California IBI in Arroyo Seco Reach 1 (LA River to West Holly Ave.) were poor in years 2003 and 2004 indicating impairment of benthic community structure. In step 3, the water quality data for coliform bacteria, trash, cyanide, pH, dissolved oxygen, nitrite, aluminum, lead, copper, zinc, and diazinon were evaluated by State Water Board staff. Data for coliform bacteria and trash were evaluated in a previous listing cycle. Coliform bacteria and showed impairment to the water contact recreation and non-contact recreation and it resulted in listing this water body in 2002 and 2006. In this step State Water Board staff evaluated the most recent available data for cyanide, pH, dissolved oxygen, nitrite, aluminum, lead, copper, zinc, and diazinon. The data for cyanide show that 4 out of 12 samples exceeded the water quality objective. The data for pH show that 1 out of 12 samples exceeded the water quality objective. The data for dissolved oxygen show that 1 out of 12 samples exceeded the water quality objective. The data for nitrite show that 1 out of 12 samples exceeded the water quality objective. The data for aluminum show that 2 out of 12 samples exceeded the water quality objective. The data for lead show that 2 out of 12 samples exceeded the water quality objective. The data for copper show that 9 out of 12 samples exceeded the water quality objective. The data for zinc show that 4 out of 12 samples exceeded the water quality objective. The data for cyanide show that 2 out of 12 samples exceeded the water quality objective. The weight of evidence of the data and information indicate that the beneficial use of the water is not supported. The water quality chemistry and bioassessment data provide a substantial basis that benthic macroinvertebrate populations are impacted by a wide range of anthropogenic stressors. Based on the available data and information, staff recommend to list for benthic macroinvertebrate-bioassessment. |
| Regional Board Decision 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. |
| State Board Review of Regional Board Conclusion and Recommendation: | In step 3, the water quality data for coliform bacteria, trash, cyanide, pH, dissolved oxygen, nitrite, aluminum, lead, copper, zinc, and diazinon were evaluated by State Water Board staff. Data for coliform bacteria and trash were evaluated in a previous listing cycle. Coliform bacteria and showed impairment to the water contact recreation and non-contact recreation and it resulted in listing this water body in 2002 and 2006. In this step State Water Board staff evaluated the most recent available data for cyanide, pH, dissolved oxygen, nitrite, aluminum, lead, copper, zinc, and diazinon. The data for cyanide show that 4 out of 12 samples exceeded the water quality objective. The data for pH show that 1 out of 12 samples exceeded the water quality objective. The data for dissolved oxygen show that 1 out of 12 samples exceeded the water quality objective. The data for nitrite show that 1 out of 12 samples exceeded the water quality objective. The data for aluminum show that 2 out of 12 samples exceeded the water quality objective. The data for lead show that 2 out of 12 samples exceeded the water quality objective. The data for copper show that 9 out of 12 samples exceeded the water quality objective. The data for zinc show that 4 out of 12 samples exceeded the water quality objective. The data for cyanide show that 2 out of 12 samples exceeded the water quality objective. The weight of evidence of the data and information indicate that the beneficial use of the water is not supported.
The water quality chemistry and bioassessment data provide a substantial basis that benthic macroinvertebrate populations are impacted by a wide range of anthropogenic stressors. Based on the available data and information, staff recommend to list for benthic macroinvertebrate-bioassessment. |
| 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. |
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| LOE ID: | 30223 | ||||
| Pollutant: | Benthic-Macroinvertebrate Bioassessments | ||||
| LOE Subgroup: | Population/Community Degradation | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Non-Contact Recreation | ||||
| Number of Samples: | 0 | ||||
| Number of Exceedances: | 0 | ||||
| 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 | ||||
| SWAMP Data: | Non-SWAMP | ||||
| 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 | ||||
| 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. Appendix 7-B Environmental Management Vol. 35, No. 4, pp. 493-504. | ||||
| Los Angeles County 1994-2005 Integrated Receiving Water Impacts Report. Section 3, Methods, pp3.1 - 3.28 | |||||
| Los Angeles County 1994-2005 Integrated Receiving Water Impacts Report. Section 5, Los Angeles River Watershed Management Area, pp5.1 - 5.40 | |||||
| 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 | ||||
| Los Angeles County 1994-2005 Integrated Receiving Water Impacts Report. Section 3, Methods, pp3.1 - 3.28 | |||||
DECISION ID |
7181 |
Region 4 |
Arroyo Seco Reach 1 (LA River to West Holly Ave.) |
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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 |
| 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): | |
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| LOE ID: | 28085 | ||||
| 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): | |||||
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| LOE ID: | 4028 | ||||
| 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 |
4311 |
Region 4 |
Arroyo Seco Reach 1 (LA River to West Holly Ave.) |
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| 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: | Pollutant |
| Regional Board Conclusion: | This condition is being considered for listing under section 2.2 of the Listing Policy. Under this section of the Policy, a minimum of two lines of evidence is needed to assess listing status.
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). Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination in the Water Quality Limited Segments Being Addressed portion of the section 303(d) list. |
| 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): | |
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| LOE ID: | 2486 | ||||
| Pollutant: | Excess Algal Growth | ||||
| 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 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 |
7179 |
Region 4 |
Arroyo Seco Reach 1 (LA River to West Holly Ave.) |
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| 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. |
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| LOE ID: | 4027 | ||||
| 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): | |||||