Draft California 2014 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 4 - Los Angeles Region

Water Body Name: San Jose Creek, unnamed tributary at Rose Hill (Los Angeles County)
Water Body ID: CAR4053100020110720114748
Water Body Type: River & Stream
Region 4     
San Jose Creek, unnamed tributary at Rose Hill (Los Angeles County)
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.The sample collected had an IBI score below 40. The score was 6.

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 sample collected had an IBI score below 40. The score was 6. However, this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 2 samples is needed to determine impairment using Table 3.1.
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: 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.
Line of Evidence (LOE) for Decision ID 66885, Benthic Community Effects
Region 4     
San Jose Creek, unnamed tributary at Rose Hill (Los Angeles County)
LOE ID: 88020
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: 1
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: One sample was collected from the San Jose Creek. The sample collected had an IBI score below 40. The score was 6 (2008).
Data Reference: Bioassessment Monitoring Report in Los Angeles County, 2006-2008.
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 station SGLR00190 Lower San Gabriel River Tributary at Rose Hill Road.
Temporal Representation: The sample was collected in 2008.
Environmental Conditions:
QAPP Information: Los Angeles County Department of Public Works (LACDPW) contracted Weston Solutions, Inc. to perform biological assessments. Sampling and analysis followed the protocols described in the California Stream Bioassessment Procedure (CSBP) (Harrington, 2003),and also incorporated the Southern California Index of Biotic Integrity (IBI) (Ode et al., 2005).
QAPP Information Reference(s):