Water Body Name: | Stokes Creek |
Water Body ID: | CAR4042202019990201161555 |
Water Body Type: | River & Stream |
DECISION ID |
66895 |
Region 4 |
Stokes Creek |
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Pollutant: | Benthic Community Effects |
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list) |
Last Listing Cycle's Final Listing Decision: | New Decision |
Revision Status | Original |
Impairment from Pollutant or Pollution: | Pollutant |
Regional Board Conclusion: | Benthic Community Effects is being considered for placement on the CWA section 303(d) List under sections 3.9 of the Listing Policy. Under section 3.9, an additional line of evidence associating the Benthic Community Effects with a water or sediment concentration of pollutants is necessary to assess listing status. The one sample collected had an IBI score above 40.
Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing Benthic Community Effects in this water segment on the CWA section 303(d) List. 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.The one sample collected had an IBI score above 40. However, this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. 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: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. |
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. |
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LOE ID: | 89455 | ||||
Pollutant: | Benthic-Macroinvertebrate Bioassessments | ||||
LOE Subgroup: | Population/Community Degradation | ||||
Matrix: | Water | ||||
Fraction: | Not Recorded | ||||
Beneficial Use: | Warm Freshwater Habitat | ||||
Number of Samples: | 1 | ||||
Number of Exceedances: | 0 | ||||
Data and Information Type: | Benthic macroinvertebrate surveys | ||||
Data Used to Assess Water Quality: | The one sample collected had an IBI score above 40. The score at site STC16 was 51. | ||||
Data Reference: | Data for abundance calculations, taxa list and IBI scores in Malibu Creek Watershed, 2006-2009. | ||||
SWAMP Data: | Non-SWAMP | ||||
Water Quality Objective/Criterion: | 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, analysis of species diversity, population density, growth anomalies, bioassays of appropriate duration or other appropriate methods as specified by the State or Regional Board. Region 4 Basin Plan. | ||||
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. For the Southern California IBI, sites with scores below 40 are considered to have impaired conditions. | ||||
Guideline Reference: | Development of a Benthic Index of Biotic Integrity (B-IBI) for Wadeable Streams in Northern Coastal California and its Application to Regional 305(b) Assessment | ||||
Spatial Representation: | The sample was collected at station STC16 Stokes Creek outlet, Malibu Creek State Park. | ||||
Temporal Representation: | The sample was collected in the fall 2006. | ||||
Environmental Conditions: | |||||
QAPP Information: | Data was collected in compliance with California Stream Bioassessment Procedure. Collection procedures were audited by California Department of Fish and Game in 2006. | ||||
QAPP Information Reference(s): | |||||
DECISION ID |
36141 |
Region 4 |
Stokes Creek |
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Pollutant: | Indicator Bacteria |
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 (being addressed by USEPA approved TMDL)(2012) |
Revision Status | Original |
Sources: | Nonpoint Source |
TMDL Name: | Malibu Pathogens (47 in part) |
TMDL Project Code: | 236 |
Date TMDL Approved by USEPA: | 01/10/2006 |
Impairment from Pollutant or Pollution: | Pollutant |
Regional Board Conclusion: | This pollutant is being considered for listing under section 2.2 of the Listing Policy. Under this section of the Policy, a minimum of one line of evidence is needed to assess listing status.
One line of evidence is available in the administrative record to assess this pollutant. A TMDL has been developed and approved by USEPA and an approved implementation plan is expected to result in attainment of the standard. The Malibu Creek Watershed Bacteria TMDL was approved by USEPA in January of 2006. Based on the readily available information, the weight of evidence indicates that there is sufficient justification in favor of 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: | 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. |
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. |
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LOE ID: | 2261 | ||||
Pollutant: | Coliform Bacteria | ||||
LOE Subgroup: | Pollutant-Water | ||||
Matrix: | Not Specified | ||||
Fraction: | None | ||||
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 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): | |||||