| Water Body Name: | Lachusa Canyon Creek |
| Water Body ID: | CAR4044200020050607193629 |
| Water Body Type: | River & Stream |
DECISION ID |
66223 |
Region 4 |
Lachusa Canyon 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 Staff 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.One of the two samples collected had an IBI score below 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.One of the two samples collected had an IBI score below 40. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. The CSCI is applicable statewide, accounts for a much wider range of natural variability, and provides equivalent scoring thresholds in all regions of the state. The CSCI will be used in the future for water quality assessment purposes statewide over the regional indices of biologic integrity (IBIs). |
| Regional Board Staff 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. |
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| LOE ID: | 85444 | ||||
| Pollutant: | Benthic-Macroinvertebrate Bioassessments | ||||
| LOE Subgroup: | Population/Community Degradation | ||||
| Matrix: | Water | ||||
| Fraction: | Not Recorded | ||||
| Beneficial Use: | Warm Freshwater Habitat | ||||
| Number of Samples: | 2 | ||||
| Number of Exceedances: | 1 | ||||
| Data and Information Type: | Benthic macroinvertebrate surveys | ||||
| Data Used to Assess Water Quality: | One of the two samples collected had an IBI score below 40. The scores at site LCH18 were 11 (fall 2006) and 57 (spring 2009). | ||||
| 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 samples were collected at stations LCH18 Lachusa Creek. | ||||
| Temporal Representation: | The samples were collected in the fall 2006 and spring 2009. | ||||
| 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 |
33321 |
Region 4 |
Lachusa Canyon Creek |
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| 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. An insufficient total number of samples were taken and 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.Three of 3 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. |
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| LOE ID: | 2277 | ||||
| Pollutant: | Sulfates | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Not Recorded | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| Number of Samples: | 3 | ||||
| Number of Exceedances: | 3 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Three samples with three exceeding. (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 Lachusa Canyon Creek Upper: 34.06672 -118.88675 and at Lachusa Canyon Creek Lower: 34.04095 -118.88919. | ||||
| Temporal Representation: | Samples were collected March 2003 through March 2004. | ||||
| Environmental Conditions: | Los Angeles County Coastal Streams: 404.42. | ||||
| QAPP Information: | SWAMP Quality Assurance Plan | ||||
| QAPP Information Reference(s): | |||||