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

Supporting Information

Regional Board 3 - Central Coast Region

Water Body Name: Pacific Ocean at Avila Beach (SLO creek mouth)
Water Body ID: 3002
Water Body Type: Coastal & Bay Shoreline
 
DECISION ID
10452
 
Pollutant: Fecal Coliform
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
 
Weight of Evidence: This water segment-pollutant combination is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this water segment-pollutant combination. Water Board staff assessed one data set against two different evaluation criteria (i.e. single sample maximum and geomean). Six of 108 samples exceeded the single sample maximum criterion and one of 24 geomean assessments exceeded the geomean criterion.

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. Six of 108 samples exceeded the single sample maximum criterion and one of 24 geomean assessments exceeded the geomean criterion 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 10452
 
LOE ID: 19211
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 24
Number of Exceedances: 1
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed data for Pacific Ocean at Avila Beach (SLO creek mouth) to determine beneficial use support and results are as follows: 1 of 24 samples exceed the criterion for Coliform, Fecal.
Data Reference: AB 411 Data for 2004
  AB 411 Data for 2005
  AB 411 Data for 2006
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2005) states that the 30-day geometric mean for fecal coliform shall not exceed 200 MPN/100 mL.
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Pacific Ocean at Avila Beach was collected at one AB411 monitoring site (AB9)
Temporal Representation: Data was collected over the time period 1/4/2005 - 12/28/2006. This includes weekly AB411 monitoring between April 1 and October 31 of each year.
Environmental Conditions:
QAPP Information: QA information not available
QAPP Information Reference(s):
 
LOE ID: 19234
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 108
Number of Exceedances: 6
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed data for Pacific Ocean at Avila Beach (SLO creek mouth) to determine beneficial use support and results are as follows: 6 of 108 samples exceed the criterion for Coliform, Fecal.
Data Reference: AB 411 Data for 2004
  AB 411 Data for 2005
  AB 411 Data for 2006
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2005) states that the single sample maximum for fecal coliform shall not exceed 400 MPN/100 mL.
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Pacific Ocean at Avila Beach was collected at one AB411 monitoring site (AB9)
Temporal Representation: Data was collected over the time period 1/4/2005 - 12/28/2006. This includes weekly AB411 monitoring between April 1 and October 31 of each year.
Environmental Conditions:
QAPP Information: QA information not available
QAPP Information Reference(s):
 
DECISION ID
10450
 
Pollutant: Total Coliform
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
 
Weight of Evidence: This water segment-pollutant combination is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this water segment-pollutant combination. Water Board staff assessed one data set against three different evaluation criteria (i.e. single sample maximum and geomean). Six of 108 samples exceeded the single sample maximum criterion, five of 24 geomean assessments exceeded the geomean criterion, and four of 108 sample ratio exceeded the total to fecal ratio criterion.

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. Six of 108 samples exceeded the single sample maximum criterion, five of 24 geomean assessments exceeded the geomean criterion, and four of 108 sample ratio exceeded the total to fecal ratio criterion 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 10450
 
LOE ID: 19237
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 108
Number of Exceedances: 6
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed data for Pacific Ocean at Avila Beach (SLO creek mouth) to determine beneficial use support and results are as follows: 6 of 108 samples exceed the criterion for Coliform, Total.
Data Reference: AB 411 Data for 2004
  AB 411 Data for 2005
  AB 411 Data for 2006
 
Water Quality Objective/Criterion: California Ocean Plan (2005) single sample maximum states that total coliform density shall not exceed 10,000 MPN/100 mL.
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Pacific Ocean at Avila Beach was collected at one monitoring site (AB9)
Temporal Representation: Data was collected over the time period 1/4/2005 - 12/28/2006. This includes weekly AB411 monitoring between April 1 and October 31 of each year.
Environmental Conditions:
QAPP Information: QA information not available
QAPP Information Reference(s):
 
LOE ID: 19239
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 108
Number of Exceedances: 4
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed data for Pacific Ocean at Avila Beach (SLO creek mouth) to determine beneficial use support and results are as follows: 4 of 108 samples exceed the criterion for Coliform, Total.
Data Reference: AB 411 Data for 2004
  AB 411 Data for 2005
  AB 411 Data for 2006
 
Water Quality Objective/Criterion: California Ocean Plan (2005) single sample maximum standard for total coliform states that total coliform density shall not exceed 1,000 MPN/100 mL when the fecal coliform/total coliform ratio exceeds 0.1.
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Pacific Ocean at Avila Beach was collected at one monitoring site (AB9)
Temporal Representation: Data was collected over the time period 1/4/2005 - 12/28/2006. This includes weekly AB411 monitoring between April 1 and October 31 of each year.
Environmental Conditions:
QAPP Information: QA information not available
QAPP Information Reference(s):
 
LOE ID: 19238
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 24
Number of Exceedances: 5
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed data for Pacific Ocean at Avila Beach (SLO creek mouth) to determine beneficial use support and results are as follows: 5 of 24 samples exceed the criterion for Coliform, Total.
Data Reference: AB 411 Data for 2004
  AB 411 Data for 2005
  AB 411 Data for 2006
 
Water Quality Objective/Criterion: California Ocean Plan (2005) 30-day geometric mean standard for total coliform states that total coliform density shall not exceed 1,000 MPN/100 mL.
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Pacific Ocean at Avila Beach was collected at one monitoring site (AB9)
Temporal Representation: Data was collected over the time period 1/4/2005 - 12/28/2006. This includes weekly AB411 monitoring between April 1 and October 31 of each year.
Environmental Conditions:
QAPP Information: QA information not available
QAPP Information Reference(s):
 
DECISION ID
10453
 
Pollutant: Enterococcus
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2021
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This water segment-pollutant combination is being considered for placement on the section 303(d) list under sections 2.1 and 3.3 of the Listing Policy. T

wo lines of evidence are available in the administrative record to assess this water segment-pollutant combination. Based on section 3.3 of the Listing Policy, the site exceeded numeric objectives for Enterococus in one of the lines of evidence. Using the binomial distribution, waters shall be placed on the section 303(d) list if the number of measured exceedances supports rejection of the null hypothesis as presented in Table 3.2.

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 Water Board 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 24 samples exceed the geomean criteria. Therefore, number of exceedances for this line of evidence exceeds the allowable frequency as 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 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 10453
 
LOE ID: 19235
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 24
Number of Exceedances: 6
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed data for Pacific Ocean at Avila Beach (SLO creek mouth) to determine beneficial use support and results are as follows: 6 of 24 samples exceed the criterion for Enterococci.
Data Reference: AB 411 Data for 2004
  AB 411 Data for 2005
  AB 411 Data for 2006
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2005) states that the geometric mean for Enterococcus shall not exceed 35 MPN/100 mL.
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Pacific Ocean at Avila Beach was collected at one AB411 monitoring site (AB9)
Temporal Representation: Data was collected over the time period 1/4/2005 - 12/28/2006. This includes weekly AB411 monitoring between April 1 and October 31 of each year.
Environmental Conditions:
QAPP Information: QA information not available
QAPP Information Reference(s):
 
LOE ID: 19236
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 111
Number of Exceedances: 11
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed data for Pacific Ocean at Avila Beach (SLO creek mouth) to determine beneficial use support and results are as follows: 11 of 111 samples exceed the criterion for Enterococci.
Data Reference: AB 411 Data for 2004
  AB 411 Data for 2005
  AB 411 Data for 2006
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2005) states that the single sample maximum for Enterococcus shall not exceed 104 MPN/100 mL.
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Pacific Ocean at Avila Beach was collected at one AB411 monitoring site (AB9)
Temporal Representation: Data was collected over the time period 1/4/2005 - 12/28/2006. This includes weekly AB411 monitoring between April 1 and October 31 of each year.
Environmental Conditions:
QAPP Information: QA information not available
QAPP Information Reference(s):