Final California 2018 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 3 - Central Coast Region

Water Body Name: Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
Water Body ID: CAX3041205320021002231123
Water Body Type: Coastal & Bay Shoreline
 
DECISION ID
72902
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
Pollutant: Enterococcus
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)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.2 and 3.3 of the Listing Policy. Under these sections, a single line of evidence is necessary to assess listing status.

Four lines of evidence are available in the administrative record to assess this pollutant. Nine of 166 samples exceeded the geometric mean standard for enterococcus (LOEs 20091 and 56504) and 11 of 264 samples exceeded the single sample maximum for enterococcus (LOEs 20092 and 56503) for the water contact recreation water quality standard (Water Quality Control Plan: Ocean Waters of California, SWRCB, 2005).

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 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. Nine of 166 samples exceeded the geometric mean standard for enterococcus (LOEs 20091 and 56504) and 11 of 264 samples exceeded the single sample maximum for enterococcus (LOEs 20092 and 56503) for the water contact recreation water quality standard 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.
 
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 because applicable water quality standards are not being exceeded.
 
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 72902, Enterococcus
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
LOE ID: 56504
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 140
Number of Exceedances: 9
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Nine of the 140 geomeans exceeded the entercoccus objective.
Data Reference: Data for Region 3 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The geometric mean standard for enterococcus states that the entercoccus density shall not exceed 35 per 100 mL. Water Quality Control Plan for Ocean Waters 2009.
Objective/Criterion Reference: California Ocean Plan Water Quality Control Plan Ocean Waters of California 2009
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Twin Lakes Beach .
Temporal Representation: Samples were collected approximately once a week from 2007 to 2010.
Environmental Conditions:
QAPP Information: The samples were collected for the Beach Watch program.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 72902, Enterococcus
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
LOE ID: 20091
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 26
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed data for Pacific Ocean at Twin Lakes Beach (Santa Cruz County) to determine beneficial use support and results are as follows: 0 of 26 samples exceed the criterion for Enterococci.
Data Reference: AB 411 Data for 2004
  AB 411 Data for 2005
  AB 411 Data for 2006
 
SWAMP Data: Non-SWAMP
 
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 Twin Lakes Beach (Santa Cruz County) was collected at one AB411 monitoring site (Twin Lakes Beach)
Temporal Representation: Data was collected over the time period 3/8/2004 - 12/26/2006. 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):
 
Line of Evidence (LOE) for Decision ID 72902, Enterococcus
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
LOE ID: 56503
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 155
Number of Exceedances: 9
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Beach Watch Program data that is collected by each County's Environmental Health Department for Pacific Ocean at Twin Lakes Beach (Santa Cruz County) to determine beneficial use support and results are as follows: 9 of 155 samples exceed the criterion for Enterococci.
Data Reference: Data for Region 3 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2005) single sample maximum for enterococcus density shall not exceed 104 per 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 Twin Lakes Beach (Santa Cruz County) was collected at 1 monitoring site [ Twin Lakes Beach]
Temporal Representation: Data was collected over the time period 1/3/2007-8/23/2010.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: Water Board staff assessed Beach Watch Program data that is collected by each County's Environmental Health Department. There is no QA Project Plan but instead each County follows their own Quality Assurance Procedures
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 72902, Enterococcus
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
LOE ID: 20092
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 109
Number of Exceedances: 2
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed data for Pacific Ocean at Twin Lakes Beach (Santa Cruz County) to determine beneficial use support and results are as follows: 2 of 109 samples exceed the criterion for Enterococci.
Data Reference: AB 411 Data for 2004
  AB 411 Data for 2005
  AB 411 Data for 2006
 
SWAMP Data: Non-SWAMP
 
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 Twin Lakes Beach (Santa Cruz County) was collected at one AB411 monitoring site (Twin Lakes Beach)
Temporal Representation: Data was collected over the time period 3/8/2004 - 12/26/2006. 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
80658
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
Pollutant: Escherichia coli (E. coli)
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)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: No new data were assessed. This decision has not changed from the 2010 listing cycle.

This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.2 and 3.3 of the Listing Policy. Under these sections, a single line of evidence is necessary to assess listing status.

The sample size for the geometric mean and single sample maximum criteria for Escherichia coli (E. coli) (LOEs 20093 and 20094 respectively) is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 26 samples is needed to determine if a beneficial use is supported using table 3.2. Therefore, the use support rating for these LOEs are set to 'insufficient information'.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of 2 samples exceeded the geometric mean standard for Escherichia coli (E. coli) (LOE 20093) and 0 of 7 samples exceeded the single sample maximum for Escherichia coli (E. coli) (LOE 20094) for the water contact recreation water quality standard (Ambient Water Quality Criteria for Bacteria, USEPA, 1986).

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 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. Zero of 2 samples exceeded the geometric mean standard for Escherichia coli (E. coli) (LOE 20093) and 0 of 7 samples exceeded the single sample maximum for Escherichia coli (E. coli) (LOE 20094) for the water contact recreation water quality standard 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.
 
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 because applicable water quality standards are not being exceeded.
 
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 80658, Escherichia coli (E. coli)
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
LOE ID: 20094
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 7
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed data for Pacific Ocean at Twin Lakes Beach (Santa Cruz County) to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for Escherichia coli.
Data Reference: AB 411 Data for 2004
  AB 411 Data for 2005
  AB 411 Data for 2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: USEPA Ambient Water Quality Criteria for Bacteria -1986.
Objective/Criterion Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Evaluation Guideline: Single sample maximum allowable density for E. coli in freshwater is 235 MPN/100mL (as stated in Table 4, page 15)
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: Data for this line of evidence for Pacific Ocean at Twin Lakes Beach (Santa Cruz County) was collected at one AB411 monitoring site (Twin Lakes Beach)
Temporal Representation: Data was collected over the time period 3/8/2004 - 12/26/2006. 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):
 
Line of Evidence (LOE) for Decision ID 80658, Escherichia coli (E. coli)
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
LOE ID: 20093
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed data for Pacific Ocean at Twin Lakes Beach (Santa Cruz County) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Escherichia coli.
Data Reference: AB 411 Data for 2004
  AB 411 Data for 2005
  AB 411 Data for 2006
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: USEPA Ambient Water Quality Criteria for Bacteria -1986.
Objective/Criterion Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Evaluation Guideline: Steady State Geometric Mean Indicator Density is 126 MPN/100mL (as stated in Table 4, Page 15).
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: Data for this line of evidence for Pacific Ocean at Twin Lakes Beach (Santa Cruz County) was collected at one AB411 monitoring site (Twin Lakes Beach)
Temporal Representation: Data was collected over the time period 3/8/2004 - 12/26/2006. 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
75785
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
Pollutant: Fecal Coliform
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)(2016)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.2 and 3.3 of the Listing Policy. Under these sections, a single line of evidence is necessary to assess listing status.

Four lines of evidence are available in the administrative record to assess this pollutant. Zero of 160 samples exceeded the geometric mean standard for fecal coliform (LOEs 20073 and 56506) and 3 of 240 samples exceeded the single sample maximum for fecal coliform (LOEs 20074 and 56505) for the water contact recreation water quality standard (Water Quality Control Plan: Ocean Waters of California, SWRCB, 2005).
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 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. Zero of 160 samples exceeded the geometric mean standard for fecal coliform (LOEs 20073 and 56506) and 3 of 240 samples exceeded the single sample maximum for fecal coliform (LOEs 20074 and 56505) for the water contact recreation water quality standard 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.
 
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 because applicable water quality standards are not being exceeded.
 
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 75785, Fecal Coliform
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
LOE ID: 20073
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 21
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed data for Pacific Ocean at Twin Lakes Beach (Santa Cruz County) to determine beneficial use support and results are as follows: 0 of 21 samples exceed the criterion for Coliform, Fecal.
Data Reference: AB 411 Data for 2004
  AB 411 Data for 2005
  AB 411 Data for 2006
 
SWAMP Data: Non-SWAMP
 
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 Twin Lakes Beach (Santa Cruz County) was collected at one AB411 monitoring site (Twin Lakes Beach)
Temporal Representation: Data was collected over the time period 3/8/2004 - 12/26/2006. 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):
 
Line of Evidence (LOE) for Decision ID 75785, Fecal Coliform
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
LOE ID: 56505
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 154
Number of Exceedances: 2
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Beach Watch Program data that is collected by each County's Environmental Health Department. E. coli data results are assessed using the Ocean Plan single sample maximum objective for fecal coliform to determine beneficial use support for the station named Pacific Ocean at Twin Lakes Beach (Santa Cruz County) and results are as follows: 2 of 154 samples exceed the criterion for Coliform, Fecal.
Data Reference: Data for Region 3 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2005) single sample maximum for fecal coliform density shall not exceed 400 per 100ml
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 Twin Lakes Beach (Santa Cruz County) was collected at 1 monitoring site [ Twin Lakes Beach]
Temporal Representation: Data was collected over the time period 1/3/2007-8/23/2010.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: Water Board staff assessed Beach Watch Program data that is collected by each County's Environmental Health Department. There is no QA Project Plan but instead each County follows their own Quality Assurance Procedures
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 75785, Fecal Coliform
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
LOE ID: 20074
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 86
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 Twin Lakes Beach (Santa Cruz County) to determine beneficial use support and results are as follows: 1 of 86 samples exceed the criterion for Coliform, Fecal.
Data Reference: AB 411 Data for 2005
  AB 411 Data for 2006
  AB 411 Data for 2004
 
SWAMP Data: Non-SWAMP
 
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 Twin Lakes Beach (Santa Cruz County) was collected at one AB411 monitoring site (Twin Lakes Beach)
Temporal Representation: Data was collected over the time period 3/8/2004 - 12/26/2006. 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):
 
Line of Evidence (LOE) for Decision ID 75785, Fecal Coliform
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
LOE ID: 56506
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 139
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: E. coli data results are assessed using the Ocean Plan objective for fecal coliform. A thirty day, rolling geomean was calculated for all data provided when four or more samples were collected within the 30 day period. 0 of the 139 geomeans exceeded the objective. Zero of the 139 geomeans exceeded the fecal coliform objective.
Data Reference: Data for Region 3 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The geometric mean standard for fecal coliform states that the fecal coliform density shall not exceed 200 per 100 mL. Water Quality Control Plan for Ocean Waters 2009.
Objective/Criterion Reference: California Ocean Plan Water Quality Control Plan Ocean Waters of California 2009
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Twin Lakes Beach.
Temporal Representation: Samples were collected approximately once a week from 2007 to 2010.
Environmental Conditions:
QAPP Information: The samples were collected for the Beach Watch program.
QAPP Information Reference(s):
 
 
DECISION ID
73629
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
Pollutant: Total Coliform
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)(2016)
Revision Status Original
Sources: A Source Unknown
Expected TMDL Completion Date: 2027
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.2 and 3.3 of the Listing Policy. Under these sections, a single line of evidence is necessary to assess listing status.

One lines of evidence are available in the administrative record to assess this pollutant. Twenty six of 155 samples (LOE 56507) exceeded the shellfish harvesting water quality objective (Water Quality Control Plan: Ocean Waters of California, SWRCB, 2009).

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. Twenty six of 155 samples (LOE 56507) exceeded the shellfish harvesting water quality objective 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 73629, Total Coliform
Region 3     
Pacific Ocean at Twin Lakes Beach (Santa Cruz County)
 
LOE ID: 56507
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Shellfish Harvesting
 
Number of Samples: 155
Number of Exceedances: 26
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Beach Watch data for Pacific Ocean at Twin Lakes Beach (Santa Cruz County) to determine beneficial use support and results are as follows: 26 of 155 samples exceed the criterion for Coliform, Total.
Data Reference: Data for Region 3 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The California Ocean Plan (2009) states the following: At all areas where shellfish may be harvested for human consumption, the following bacterial objectives shall be maintained throughout the water column: Ten percent of the samples collected during any 30-day period shall not exceed 230 MPN/100mL.
Objective/Criterion Reference: California Ocean Plan Water Quality Control Plan Ocean Waters of California 2009
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Pacific Ocean at Twin Lakes Beach (Santa Cruz County) was collected at 1 monitoring site [ Twin Lakes Beach]
Temporal Representation: Data was collected over the time period 1/3/2007-8/23/2010.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The samples were collected for the Beach Watch program.
QAPP Information Reference(s):