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

Supporting Information

Regional Board 9 - San Diego Region

Water Body Name: San Marcos Creek
Water Body ID: CAR9045100020011025132925
Water Body Type: River & Stream
 
DECISION ID
17909
 
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.

Two lines of evidence are available in the administrative record to assess this indicator. 38 of 38 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. 38 of 38 samples exceeded the Index of Biological Integrity (IBI) value of "poor" water quality for this area and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy, however as required under section 3.9 of the Listing Policy, pollutant(s) could not be directly associated with the Benthic Community Effects.
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 it cannot be determined if applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 17909
 
LOE ID: 26446
 
Pollutant: Benthic Community Effects
LOE Subgroup: Adverse Biological Responses
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 24
Number of Exceedances: 24
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: Twenty four samples of IBI data were taken from May 1998 to November 2000 at four sampling sites. Of the total number of samples, all twenty 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 four sites: 904SMCLCC, 904SMCMxx, 904SMCRSF, and 904SMCSPx on San Marcos Creek.
Temporal Representation: Sampling occurred during one to seven events annually from May 1998 to November 2000.
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
 
LOE ID: 27029
 
Pollutant: Benthic Community Effects
LOE Subgroup: Adverse Biological Responses
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 14
Number of Exceedances: 14
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: Fourteen samples of IBI data were taken from May 2001 to October 2004 at four sampling sites. Of the total number of samples, all fourteen of the samples exceeded the IBI impairment threshold.
Data Reference: Stream Bioassessment Data. Co-permitee Data. Collected 2002-2007.
 
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.
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 four sites: SMC-LCCC, SMC-M, SMC-RSFR, and SMC-SP on San Marcos Creek.
Temporal Representation: Sampling occurred during May and October annually over a two year period from May 2001 to October 2002 and during October 2004.
Environmental Conditions:
QAPP Information: Quality Control for collection and identification was conducted in accordance with the Quality Assurance Manual for Freshwater Bioassessment.
QAPP Information Reference(s): QUALITY ASSURANCE MANUAL FOR FRESHWATER BIOASSESSMENT Revision 0
 
DECISION ID
6757
 
Pollutant: Sediment Toxicity
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2006)
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 removal from the section 303(d) list under section 4.6 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess pollutant. Ten of 16 samples exceed the water quality objective for sediment toxicity.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the 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. Ten of 16 samples exceed the water quality objective for sediment toxicity, and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are 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 removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 6757
 
LOE ID: 3209
 
Pollutant: Sediment Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 2
 
Data and Information Type: Chemical monitoring of sediments
Data Used to Assess Water Quality: Two out of four samples displayed statistically significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%. One of the four samples (collected April 23, 2002) also displayed statistically significant toxicity in the survival endpoint compared to the negative control, but this data point is not included in the total 'toxic' samples as it had a data qualifier. All samples were tested using the 10-day Hyallela azteca test (SWAMP, 2004).
Data Reference: Placeholder reference 2006 303(d)
 
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, 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 (Region 9 Basin Plan, pages 3-15 to 3-16; September 8, 1994).
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: All samples were collected from one station, San Marcos Creek 6.
Temporal Representation: Samples were collected from March 2002 through September 2002. Toxicity in the survival endpoint was detected in samples collected on March 13, 2002 and September 17, 2002.
Environmental Conditions:
QAPP Information: SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 3208
 
Pollutant: Sediment Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 2
 
Data and Information Type: Chemical monitoring of sediments
Data Used to Assess Water Quality: Two out of four samples displayed statistically significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%. One of the four samples (collected April 23, 2002) also displayed statistically significant toxicity in the survival endpoint compared to the negative control, but this data point is not included in the total 'toxic' samples as it had a data qualifier. All samples were tested using the 10-day Hyallela azteca test (SWAMP, 2004).
Data Reference: Placeholder reference 2006 303(d)
 
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, 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 (Region 9 Basin Plan, pages 3-15 to 3-16; September 8, 1994).
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: All samples were collected from one station, San Marcos Creek 3.
Temporal Representation: Samples were collected from March 2002 through September 2002. Toxicity in the survival endpoint was detected in samples collected on March 12, 2002 and September 18, 2002.
Environmental Conditions:
QAPP Information: SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 21385
 
Pollutant: Toxicity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 8
Number of Exceedances: 6
 
Data and Information Type: Ambient toxicity testing (chronic)
Data Used to Assess Water Quality: Total of eight samples were collected, four at San Marcos Creek station 904CBSAM3and four at San Marcos Creek station 904CBSAM6. They showed significant toxicity levels (SL) in the following tests: Selenastrum algae growth test - six of the eight samples. Ceriodaphnia dubia survival/reproductive test -four of the eight samples. Samples were collected in 2002. Tests results can be found in California's Surface Water Ambient Monitoring Program Report, 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.
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: Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. Fourth Edition. Office of Water, U.S. Environmental Protection Agency. Washington, D.C. EPA-821-R-02-013
 
Spatial Representation: Samples were collected from stations San Marcos Creek 3 (904CBSAM3) and San Marcos Creek 6 (904CBSAM6).
Temporal Representation: Samples were collected on March, April, June and September 2002.
Environmental Conditions:
QAPP Information: Quality control for the chemical analysis portion of this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program.
QAPP Information Reference(s):
 
DECISION ID
5766
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
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)(2006)
Revision Status Original
Impairment from Pollutant or Pollution: Pollution
 
Weight of Evidence: Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against 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 the four lines of evidence in the record to assess this pollutant consists of bioassessment data. This information on its own is insufficient to determine with the confidence and power required by the Listing Policy since this data is not associated with water or sediment concentrations of pollutants (Policy Section 3.9).
 
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 it cannot be determined if applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation: After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are exceeded.
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 5766
 
LOE ID: 3205
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Not Specified
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: Data were collected for the San Diego Regional Water Quality Control Board 1999 Biological Assessment Annual Report. Physical habitat scores for SMC-SP ranged from 90 to 120, moderate scores, compared to other sampled waterbodies. BMI scores were below average. In May and September 1998, the scores were just slightly below average, but decreased further below average in November 1998 and May 1999. (SWRCB, 2003).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion:
Objective/Criterion Reference:
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at San Marcos Creek, 5 riffles downstream of Santar Place (SMC-SP).
Temporal Representation: Samples were collected in May, September, November 1998 and in May 1999.
Environmental Conditions:
QAPP Information: Data used in 2002 assessment.
QAPP Information Reference(s):
 
LOE ID: 3206
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Not Specified
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: Data were collected for the San Diego Regional Water Quality Control Board 1999 Biological Assessment Annual Report. Physical habitat scores ranged from 108 to 128, higher scores compared to other sampled waterbodies. BMI scores were either at, slightly above, or slightly below average. (SWRCB, 2003).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion:
Objective/Criterion Reference:
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at San Marcos Creek, 5 riffles 50m upstream of McMahr Rd intersection (SMC-RSFR).
Temporal Representation: Samples were collected in May, September, November 1998, and May 1999.
Environmental Conditions:
QAPP Information: Data used in 2002 assessment.
QAPP Information Reference(s):
 
LOE ID: 3207
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Not Specified
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: Data were collected for the San Diego Regional Water Quality Control Board 1999 Biological Assessment Annual Report. Physical habitat scores for SMC-LCCC ranged from 104 to 132, higher scores compared to other sampled waterbodies. BMI scores were near average for the sampling months (3 at or slightly above, 1 slightly below). (SWRCB, 2003).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion:
Objective/Criterion Reference:
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at San Marcos Creek, 5 riffles downstream of Rancho Santa Fe Rd (SMC-LCCC).
Temporal Representation: Samples were collected in May, September, November 1998 and May 1999.
Environmental Conditions:
QAPP Information: Data used in 2002 assessment.
QAPP Information Reference(s):
 
LOE ID: 3204
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Not Specified
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: Samples were collected for the San Diego Regional Water Quality Control Board 1999 Biological Assessment Annual Report. Physical habitat scores at SMC-M ranged from 107 to 126, moderate compared to other sampled waterbodies. BMI scores were above and below average. Of the 4 scores, 3 were below average, and 1 was above. (SWRCB, 2003).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion:
Objective/Criterion Reference:
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at San Marcos Creek, 5 riffles 50m upstream of McMahr Rd. intersection (SMC-M).
Temporal Representation: Samples were collected in May, September, November 1998, and May 1999.
Environmental Conditions:
QAPP Information: Data used in 2002 assessment.
QAPP Information Reference(s):
 
DECISION ID
5764
 
Pollutant: Total Dissolved Solids
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)(2006)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2, one line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Two of two of the samples exceed the Basin Plan water quality objective for total dissolved solids.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against 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. Two of two of the samples exceed the Basin Plan water quality objective for total dissolved solids, and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of five samples is needed for application of table 3.2.
4. Pursuant to [SECTION 3.11/4.11] 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 it cannot be determined if applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 5764
 
LOE ID: 3201
 
Pollutant: Total Dissolved Solids
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total Dissolved
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data were collected by RWQCB9 in 1998. One sample was collected, it was in exceedance. (SWRCB, 2003).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion: From the Basin Plan: For inland surface waters and all beneficial uses, the WQO for TDS is 500 mg/L. This concentration is not to be exceeded more than 10% of the time during any one year period.
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Sample was collected at San Marcos Creek at Rancho Santa Fe Rd.
Temporal Representation: Sample was collected on 06/03/1998.
Environmental Conditions:
QAPP Information: Data used in 2002 assessment.
QAPP Information Reference(s):
 
LOE ID: 3200
 
Pollutant: Total Dissolved Solids
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total Dissolved
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data were collected by RWQCB9 in 1998. One sample was collected, it was in exceedance. (SWRCB, 2003).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion: From the Basin Plan: For inland surface waters and all beneficial uses, the WQO for TDS is 500 mg/L. This concentration is not to be exceeded more than 10% of the time during any one year period.
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Sample was collected at San Marcos Creek at Mcmahr.
Temporal Representation: Sample was collected on 06/03/1998.
Environmental Conditions:
QAPP Information: Data used in 2002 assessment.
QAPP Information Reference(s):
 
DECISION ID
5765
 
Pollutant: Turbidity
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)(2006)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2, one line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Neither of the two samples exceed the Basin Plan water quality objective for turbidity.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against 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. Neither of the two samples exceed the Basin Plan water quality objective for turbidity, and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of five samples is needed for application of table 3.2.
4. Pursuant to [SECTION 3.11/4.11] 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 it cannot be determined if applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 5765
 
LOE ID: 3202
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data were collected by RWQCB9 in 1998. One sample was collected and was not in exceedance (SWRCB, 2003).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion: From the Basin Plan: For inland surface waters and all beneficial uses, the WQO for turbidity is 20 ntu. This concentration is not to be exceeded more than 10% of the time during any one year period.
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Sample was collected at San Marcos Creek at Rancho Santa Fe Rd.
Temporal Representation: Sample was collected on 06/03/1998.
Environmental Conditions:
QAPP Information: Data used in 2002 assessment.
QAPP Information Reference(s):
 
LOE ID: 3203
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data were collected by RWQCB9 in 1998. 1 sample was collected and was not in exceedance (SWRCB, 2003).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion: From the Basin Plan: For inland surface waters and all beneficial uses, the WQO for turbidity is 20 ntu. This concentration is not to be exceeded more than 10% of the time during any one year period.
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at San Marcos Creek at McMahr.
Temporal Representation: Samples were collected on 06/03/1998.
Environmental Conditions:
QAPP Information: Data used in 2002 assessment.
QAPP Information Reference(s):
 
DECISION ID
5404
 
Pollutant: DDE (Dichlorodiphenyldichloroethylene)
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2006)
Revision Status Original
Sources: Source Unknown
Expected TMDL Completion Date: 2019
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for removal from the section 303(d) list under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess pollutant. Three of four of samples exceed the Basin Plan water quality objective for DDE.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the 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. Three of four of samples exceed the Basin Plan water quality objective for DDE, and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are 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 removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 5404
 
LOE ID: 3211
 
Pollutant: DDE (Dichlorodiphenyldichloroethylene)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 3
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Four samples; three samples exceeding (SWAMP, 2004).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion: California Toxic Rule: Human Health-FW (water & organisms) .00059 mg/L.

San Diego RWQCB Basin Plan: No individual pesticide or combination of pesticides shall be present in the water column, sediments, or biota at concentration(s) that adversely affect beneficial uses.
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One Station at San Marcos Creek: 33.13027 -117.192.
Temporal Representation: Samples were collected from March through September of 2002.
Environmental Conditions: San Marcos Creek Watershed 904.51.
QAPP Information: SWAMP Quality Assurance Plan.
QAPP Information Reference(s):
 
DECISION ID
5344
 
Pollutant: Phosphorus
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2006)
Revision Status Original
Sources: Source Unknown | 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 removal from the section 303(d) list under section 4.2 of the Listing Policy. Under this section 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 eight of samples exceed the Basin Plan water quality objective for phosphorus.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the 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. Eight of eight of samples exceed the Basin Plan water quality objective for phosphorus, and this exceeds the allowable frequency listed in Table 4.2 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are 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 removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 5344
 
LOE ID: 3210
 
Pollutant: Phosphorus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 8
Number of Exceedances: 8
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Eight water samples, eight samples exceeding (SWAMP, 2004).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growth to the extent that such growth causes nuisances or adversely affects beneficial uses. Water Quality Control Plan for the San Diego Basin Goal of 0.1 mg/L in stream and flowing waters.
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Two stations at San Marcos Creek: 33.13027 - 117.192
and at 33.08791 - 117.26933.
Temporal Representation: Eight samples collected from March through September of 2002.
Environmental Conditions: San Marcos Creek Watershed 904.5.
QAPP Information: SWAMP Quality Assurance Plan.
QAPP Information Reference(s):
 
DECISION ID
17066
 
Pollutant: Selenium
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Original
Sources: Source Unknown
Expected TMDL Completion Date: 2021
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.

Three lines of evidence are available in the administrative record to assess this pollutant. Seven of eight of the samples exceed the California Toxics Rule water quality objective for selenium.

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. Seven of eight of the samples exceed the California Toxics Rule water quality objective for selenium, 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 17066
 
LOE ID: 8878
 
Pollutant: Selenium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 5
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Eight water samples were collected at San Marcos Creek stations 904CBSAM6 on March, April, June and September 2002. Seven of eight samples showed excessive selenium concentrations according to results in California's Surface Water Ambient Monitoring Program Report, 2007.
Data Reference: Monitoring data for Region 9
 
Water Quality Objective/Criterion: CTR Freshwater Chronic (CCC) 5 ug/L; (U.S. EPA, 2000).
Objective/Criterion Reference: Water Quality Control Plan for the San Diego Basin (9).
  Water Quality Standards; Establishment of Numeric Criteria for Priority Toxic Pollutants for the State of California; Rule. 40 CFR Part 131. U.S. Environmental Protection Agency, Region IX, Water Division, San Francisco, CA.
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Water samples were collected at San Marcos Creek stations (904CBSAM6), and station (904CBSAM3) (Latitude 33.129985, Longitude -117.19242).
Temporal Representation: Samples were collected on March, April, June and September 2002.
Environmental Conditions:
QAPP Information: Quality control for the chemical analysis portion of this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program.
QAPP Information Reference(s): 2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA.