Draft California 2024 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 4 - Los Angeles Region

Water Body Name: Santa Clara River Reach 4A (A Street, Fillmore to Piru Creek)
Water Body ID: CAR4034100020140626054411
Water Body Type: River & Stream
 
DECISION ID
151118
Region 4     
Santa Clara River Reach 4A (A Street, Fillmore to Piru Creek)
 
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 Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Benthic Community Effects are being considered for placement on the CWA section 303(d) List under sections 3.9 of the Listing Policy. Under section 3.9, additional lines of evidence (LOEs) associating the Benthic Community Effects decision with a water or sediment concentration of pollutants other than benthic-macroinvertebrate bioassessment or habitat assessment LOEs are necessary to place a water body on the 303(d) List for Benthic Community Effects.

Two line(s) of evidence evaluating benthic-macroinvertebrate bioassessment data is/are available in the administrative record to assess this indicator. One of two benthic-macroinvertebrate samples exceed the California Stream Condition Index (CSCI) impairment threshold. However, a minimum of two benthic-macroinvertebrate samples are needed to assess listing status & an aquatic life pollutant listing.

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 waterbody 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 two benthic-macroinvertebrate bioassessment samples had CSCI scores below 0.79. The available information is insufficient to determine whether the waterbody/pollutant combination should be placed on the 303(d) List of impaired waters at this time.
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:
 
 
Line of Evidence (LOE) for Decision ID 151118, Benthic Community Effects
Region 4     
Santa Clara River Reach 4A (A Street, Fillmore to Piru Creek)
 
LOE ID: 305292
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Water
Fraction: None
 
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: Water Board staff assessed data for 403STC008 to determine beneficial use support and the results are as follows: 1 of 2 samples exceeded the threshold. CSCI scores were from 0.668743978 to 0.828517693.
Data Reference: California Stream Condition Index (CSCI) Scores for the 2024 Integrated Report for Region 4.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are lethal to or that produce significant alterations in population or community ecology or receiving water biota. In addition, the health and life history characteristics of aquatic organisms in waters affected by controllable water quality factors shall not differ significantly from those for the same waters in areas unaffected by controllable water quality factors.
Objective/Criterion Reference: Water Quality Control Plan Los Angeles Region R4 Basin Plan
 
Evaluation Guideline: The California Stream Condition Index (CSCI) is a biological scoring tool that helps aquatic resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score is calculated by comparing the expected condition with actual (observed) results (Rehn, A.C. et al., 2015). CSCI scores range from 0 (highly degraded) to greater than 1 (equivalent to reference). CSCI scoring of biological condition are as follows (per the scientific paper supporting the development of the CSCI scoring tool): greater than or equal to 0.92 = likely intact condition, 0.91 to 0.80 = possibly altered condition, 0.79 to 0.63 = likely altered condition, less than or equal to 0.62 = very likely altered condition. Sites with scores below 0.79 are considered to have exceeded the water quality objective for the aquatic life beneficial use. 
Guideline Reference: Bioassessment in complex environments: designing an index for consistent meaning in different settings
 
Spatial Representation: Samples were collected from station 403STC008.
Temporal Representation: Samples were collected from 11/6/2001 to 2/4/2003.
Environmental Conditions:
QAPP Information: Data were collected using Surface Water Ambient Monitoring Program protocols
QAPP Information Reference(s): This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.
 
 
DECISION ID
99414
Region 4     
Santa Clara River Reach 4A (A Street, Fillmore to Piru Creek)
 
Pollutant: Trash
Final Listing Decision: List on 303(d) list (being addressed by action other than TMDL)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (being addressed by action other than TMDL)(2016)
Revision Status Original
Sources: A Source Unknown
Expected Attainment Date: 2027
Implementation Action Other than TMDL: Trash related impairment is being addressed by implementation actions required under State Water Resources Control Board Resolution 2015-0019 ¿Amendment to the Water Quality Control Plan for Ocean Waters of California to Control Trash and Part 1 Trash Provisions of the Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California¿
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.7 of the Listing Policy. Under section 3.7 a single line of evidence is necessary to assess listing status.

1 line of evidence is available in the administrative record to assess this pollutant.
8 of 9 samples exceeded the guideline.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination 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. 8 of 9 samples exceed the guideline and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy.
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 be placed on the section 303(d) list because 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.
 
 
Line of Evidence (LOE) for Decision ID 99414, Trash
Region 4     
Santa Clara River Reach 4A (A Street, Fillmore to Piru Creek)
 
LOE ID: 96082
 
Pollutant: Trash
LOE Subgroup: Pollutant-Nuisance
Matrix: Not Specified
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 9
Number of Exceedances: 8
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Eight of the 9 samples exceed the narrative objective. Trash was observed and counted as part of the sampling efforts of the Ventura Coastkeepers.
Data Reference: Data for Various Pollutants from Wishtoyo Foundation's Ventura Coastkeeper, 2009-2010.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: From the Los Angeles RWQCB Basin Plan: Waters shall not contain floating materials, including solids, liquids, foams, and scum, in concentrations that cause nuisance or adversely affect beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan Los Angeles Region R4 Basin Plan
 
Evaluation Guideline: The Los Angeles River Trash TMDL derived a numeric target for trash to evaluate the narrative guidelines listed in the Basin Plan. This target was derived as 0 for trash to fully support beneficial uses and also includes a margin of safety.
Guideline Reference: Trash Total Maximum Daily Loads for the Los Angeles River Watershed Revised Draft Staff Report. California Regional Water Quality Control Board, Los Angeles Region. July 27, 2007.
 
Spatial Representation: The following sites were surveyed:
SC-06 (Santa Clara River, Highway 23 Bridge, Fillmore, Friends of Santa Clara SC-06 Site)
SC-08 (Santa Clara River, Torrey Road Bridge, Downstream Piru Creek Confluence)
Temporal Representation: Sites were surveyed during the following time periods:
7/25/2009, 8/30/2009, 9/27/2009, 10/28/2009, 3/26/2010, 5/25/2010. 7/18/2010, and 8/20/2010.
Environmental Conditions:
QAPP Information: Wishtoyo Foundation volunteer monitoring QAPP was provided.
QAPP Information Reference(s): Quality Assurance Project Plan from Wishtoyo Foundation.