Draft 2008 California 303(d)/305(b) Integrated Report

Supporting Information

Regional Board 9 - San Diego Region

Water Body Name: Arroyo Trabuco Creek
Water Body ID: CAR9012000020011025103603
Water Body Type: River & Stream
 
DECISION ID
17889
 
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: Pollution
 
Weight of Evidence: Benthic Community Effects is being considered for placement on the section 303(d) list under sections 3.9 and 3.2 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 line of evidence is available in the administrative record to assess this indicator. 4 of 8 samples exceeded the water quality objective.

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 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. 4 of 8 samples exceeded the Index of Biological Integrity (IBI) value of "poor" water quality for this area and this does not exceed 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.
 
RWQCB Board Decision / Staff 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 because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 17889
 
LOE ID: 26351
 
Pollutant: Benthic Community Effects
LOE Subgroup: Adverse Biological Responses
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 8
Number of Exceedances: 4
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: Eight samples of IBI data were taken from September 1998 to June 2005 at two sampling sites. Of the total number of samples, four samples exceeded the IBI impairment threshold.
Data Reference: Fish and Game IBI Data
 
Water Quality Objective/Criterion: From the San Diego Basin Plan the objective is: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, 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 appropriate methods as specified by the Regional Board. (SDRWQCB, 1995)
Objective/Criterion Reference: Water Quality Control Plan for the San Diego Basin (9).
 
Evaluation Guideline: The Index of Biological Integrity (IBI) is an analytical tool that can be used to assess the biological and physical condition of streams and rivers within a zero to one hundred scoring range: Very Poor 0-19, Poor 20-39, Fair 40-59, Good 60- 79, Very Good 80-100. The IBI score of 39 was set as an impairment threshold because it is a statistical criterion of two standard deviations below the mean reference site score which defines the boundary between 'fair' and 'poor' IBI creek conditions. (Ode, p. 9)
Guideline Reference: "A Quantitative Tool for Assessing the Integrity of Southern Coastal California Streams". Environmental Management. Volume 35, number 1 (2005): 1-13.
 
Spatial Representation: Samples were collected at two sites: 901ATCAPx and 901ATCTCx on Arroyo Trabuco Creek.
Temporal Representation: Sampling occurred during one to two events annually over a four year period from September 1998 to May 2001 and another event on June 2005.
Environmental Conditions:
QAPP Information: Quality Control for collection and identification was conducted in accordance with the Quality Assurance Project Plan for the California Stream Bioassessment Procedure and the State of California, California Monitoring an Assessment Program: "CMAP", Quality Assurance Project Plan.
QAPP Information Reference(s): State of California, California Monitoring and Assessment Program: "CMAP".
  Quality Assurance Project Plan for the California Stream Bioassessment Procedure
  The San Diego Stream Team Quality Assurance Project Plan
 
DECISION ID
16346
 
Pollutant: Diazinon
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: Agriculture | Contaminated Sediments | Source Unknown | Unknown Nonpoint Source | Urban Runoff/Storm Sewers
Expected TMDL Completion Date: 2019
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence are available in the administrative record to assess this pollutant. Six of the 6 samples exceed the Diaznon water quality objective.

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 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. Six of 6 samples exceed the Basin Plan objectives for Diaznon and this exceeds the allowable frequency listed in Table 3.1 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.
 
RWQCB Board Decision / Staff 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.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 16346
 
LOE ID: 21274
 
Pollutant: Diazinon
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 6
 
Data and Information Type: Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: All 6 samples taken exceeded the 0.17 µg/L limit for diazinon. Samples were collected six times from March 25, 1999 to February 23, 2000. Data was submitted into the Department of Pesticide Regulation’s Surface Water Database .
Data Reference: Department of Pesticide Regulation (DPR), 2003. Surface Water Database, April 2003. Accessed July 8, 2007.
 
Water Quality Objective/Criterion: No individual pesticide or combination of pesticides shall be present in the water column, sediments of biota at concentration(s) that adversely affect beneficial uses. Pesticides shall not be present at levels which will bioaccumulate in aquatic organisms to levels which are harmful to human health, wildlife or aquatic organism. (RWQCB, 2007)
Objective/Criterion Reference: Water Quality Control Plan for the San Diego Basin (9).
 
Evaluation Guideline: Diazinon is toxic to birds and aquatic life; especially invertebrates. The one-hour average concentration of diazinon should not exceed 0.17 µg/L more than once every three years on the average (acute criterion) and the four-day average concentration of diazinon should not exceed 0.17 µg/L more than once every three years on the average (chronic criterion). (U.S. EPA, 2006).
Guideline Reference: Fact Sheet: Final Recommended Aquatic Life Ambient Water Quality Criteria for Diazinon.
 
Spatial Representation: Samples were collected from the middle Trabuco Creek at Oso Parkway. Lat/Long: 33.5850/-117.6358.
Temporal Representation: Samples were taken on various dates starting March 25, 1999 to February 23, 2000.
Environmental Conditions:
QAPP Information: Data submitted to the DPR’s Surface Water Database is subject to the document “Requirements for Inclusion of Monitoring Data in DPR’s Surface Water Database.”
QAPP Information Reference(s):
 
DECISION ID
16347
 
Pollutant: Phosphorus
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: Natural Sources | Source Unknown | Urban Runoff/Storm Sewers
Expected TMDL Completion Date: 2019
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence are available in the administrative record to assess this pollutant. Nine of the 9 samples exceed the phosphorus water quality objective.

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 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. Nine of 9 samples exceed the Basin Plan objective for phosporus and this exceeds the allowable frequency listed in Table 3.1 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.
 
RWQCB Board Decision / Staff 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.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 16347
 
LOE ID: 7733
 
Pollutant: Phosphorus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 9
Number of Exceedances: 9
 
Data and Information Type: Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: All nine flow-weighted event mean concentrations exceeded the water quality objective according to results in the the Orange County Stormwater Program annual progress reports. Samples were collected from December 2002 to March 2006.
Data Reference: Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)
 
Water Quality Objective/Criterion: Water bodies shall not contain biostimulatory substances in concentrations that promote aquatic growth to the extent that such growths cause nuisance or adversely affect beneficial uses (RWQCB, 2007).
The Water Quality Control Plan for the San Diego Basin (9) goal for phosphorus in streams and other flowing waters is 0.1 mg/L.
Objective/Criterion Reference: Water Quality Control Plan for the San Diego Basin (9).
 
Evaluation Guideline:
Guideline Reference: Water Quality Control Plan for the San Diego Basin (9).
 
Spatial Representation: Samples were collected at the mass loading station TCOL02 at Del Obispo Street at 33.4975°, 117.6657°.
Temporal Representation: Samples were collected from December 2002 to March 2006.
Environmental Conditions: Samples were collected during storm events.
QAPP Information: Quality control for the bacteria analysis portion of this study was conducted in accordance with the County of Orange Quality Assessment/Quality Control documents for their stormwater monitoring program.
QAPP Information Reference(s): Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)
 
DECISION ID
16348
 
Pollutant: Total Nitrogen as N
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: Agriculture | Natural Sources | Unknown Nonpoint Source | Urban Runoff/Storm Sewers
Expected TMDL Completion Date: 2019
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 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. Eight of the 9 samples exceed the water quality objective for total nitrogen.

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 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. Eight of 9 samples exceed the Basin Plan objective for total nitrogen as N and this exceeds the allowable frequency listed in Table 3.1 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.
 
RWQCB Board Decision / Staff 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.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 16348
 
LOE ID: 7735
 
Pollutant: Total Nitrogen as N
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 9
Number of Exceedances: 8
 
Data and Information Type: Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: Eight of nine flow-weighted event mean concentrations exceeded the water quality objective according to results in the Orange County Stormwater Program annual progress reports. Samples were collected nine times from December 2002 to March 2006.
Data Reference: Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)
 
Water Quality Objective/Criterion: Water bodies shall not contain biostimulatory substances in concentrations that promote aquatic growth to the extent that such growths cause nuisance or adversely affect beneficial uses (RWQCB, 2007).
The Water Quality Control Plan for the San Diego Basin (9) states: “A desired goal in order to prevent plant nuisance in streams and other flowing waters appears to be 0.1 mg/L total P. These values are not to be exceeded more than 10% of the time unless studies of the specific water body in question clearly show that water quality objective changes are permissible and changes are approved by the Regional Board. Analogous threshold values have not been set for nitrogen compounds; however, natural ratios of nitrogen to phosphorus are to be determined by surveillance and monitoring and upheld. If data are lacking, a ratio of N:P = 10:1, on a weight to weight basis shall be used.” Since the goal for total phosphorus is 0.1 mg/L, then according to the ratio provided, the goal for total nitrogen is 1 mg/L.
Objective/Criterion Reference: Water Quality Control Plan for the San Diego Basin (9).
 
Evaluation Guideline:
Guideline Reference: Water Quality Control Plan for the San Diego Basin (9).
 
Spatial Representation: Samples were collected at the mass loading station at Del Obispo Street at 33.4975°, 117.6657°. Station identification number is TCOL02.
Temporal Representation: Samples were collected during two to four storm events a year from December 2002 to March 2006.
Environmental Conditions: Samples were collected during wet weather.
QAPP Information: Quality control for the bacteria analysis portion of this study was conducted in accordance with the County of Orange Quality Assessment/Quality Control documents for their stormwater monitoring program.
QAPP Information Reference(s): Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)
 
DECISION ID
16349
 
Pollutant: Toxicity
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: Unknown Nonpoint Source | Unknown Point Source | Urban Runoff/Storm Sewers
Expected TMDL Completion Date: 2019
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under section 3.6 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. Six of the 14 samples exceed the water quality objective for toxicity.

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 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.Six of the 14 samples exceed the Basin Plan Objective for toxicity and this exceeds the allowable frequency listed in Table 3.1 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.
 
RWQCB Board Decision / Staff 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.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 16349
 
LOE ID: 7732
 
Pollutant: Toxicity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: Ambient toxicity testing (chronic)
Data Used to Assess Water Quality: From the four samples, there was no observed acute or chronic toxicity to Hyalella azteca, Selenastrum Algae Growth or Ceriodaphnia dubia. Toxicity data reviewed came from the Orange County Water Annual Progess Report from 2002 to 2006. Samples were collected from December 2002 through May 2005.
Data Reference: Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)
 
Water Quality Objective/Criterion: All waters shall be sustain free from toxic substances in concentrations that are toxic to, or that produce harmful physiological responses in human, plant, animal, or aquatic life.
Samples were found to exhibit toxicity when the No Observed Effect Concentration (NOEC) or median lethal concentration (LC50) for any given species was estimated to be less than 100% of the test sample concentration.
Objective/Criterion Reference: Water Quality Control Plan for the San Diego Basin (9).
 
Evaluation Guideline:
Guideline Reference: Water Quality Control Plan for the San Diego Basin (9).
 
Spatial Representation: Samples were collected at two locations in Trabuco Creek. Samples were collected at the end of Avery Parkway (TC-AP) and at Del Obispo Rd (TC-DO).
Temporal Representation: Samples were collected from December 2002 to May 2005.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion of this study was conducted in accordance with the County of Orange Quality Assessment/Quality Control documents for their stormwater monitoring program.
QAPP Information Reference(s): Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)
 
LOE ID: 26224
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 5
 
Data and Information Type: Ambient toxicity testing (chronic)
Data Used to Assess Water Quality: Five of the six samples collected show significant toxicity levels (SL). Ceriodaphnia dubia: Three of the six samples exhibited toxicity. Selenastrum capricornutum: Three of the six samples exhibited toxicity as determined by the Ceriodaphnia dubia survival/reproductive test (SWAMP, 2007).
Data Reference: Monitoring data for Region 9
 
Water Quality Objective/Criterion: From the Basin Plan, all waters shall be free of toxic substances that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life (RWQCB, 2007).
Objective/Criterion Reference: Water Quality Control Plan for the San Diego Basin (9).
 
Evaluation Guideline: According to SWAMP, waters are considered toxic when samples show significant toxicity levels (SWAMP code ‘SL’) when compared to a negative control. Significant toxicity is determined when statistical tests result in an alpha of less than 5% and percent control values less than the evaluation threshold.
Guideline Reference: 2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA.
 
Spatial Representation: Samples were collected at two locations in Trabuco Creek. Samples were collected at the end of Trabuco Creek 5 (901 SJATC5) and Trabuco Creek 2 (901 SJATC2).
Temporal Representation: Water samples were collected on October 2002, January 2003, April 2003, and May 2003.
Environmental Conditions:
QAPP Information: Quality control for this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program.
QAPP Information Reference(s): Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)
 
LOE ID: 26272
 
Pollutant: Sediment Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: Not Recorded
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 1
 
Data and Information Type: Ambient toxicity testing (chronic)
Data Used to Assess Water Quality: One of the four samples collected show significant toxicity levels (SL) to Hyalella azteca according to results from the Surface Ambient Monitoring Program results (SWAMP, 2007).
Data Reference: Monitoring data for Region 9
 
Water Quality Objective/Criterion: From the Basin Plan, all waters shall be free of toxic substances that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life (RWQCB, 2007).
Objective/Criterion Reference: Water Quality Control Plan for the San Diego Basin (9).
 
Evaluation Guideline: According to SWAMP, waters are considered toxic when samples show significant toxicity levels (SWAMP code ‘SL’) when compared to a negative control. Significant toxicity is determined when statistical tests result in an alpha of less than 5% and percent control values less than the evaluation threshold.
Guideline Reference: 2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA.
 
Spatial Representation: Water samples were collected at Trabucco Creek station Trabuco Creek 2, 901SJATC2 and Trabuco Creek 5, 901SJATC5.
Temporal Representation: Water samples were collected on October 2002, January 2003, and May 2003.
Environmental Conditions:
QAPP Information: Quality control for this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program.
QAPP Information Reference(s): Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)