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

# Supporting Information

## Regional Board 3 - Central Coast Region

Water Body Name: | Schwan Lake
Water Body ID: | CAL3041205319981209102156
Water Body Type: | Lake & Reservoir

DECISION ID | 11604
Pollutant: | Low Dissolved Oxygen
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 pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 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. Three of the 8 samples exceed the Warm Freshwater Habitat water quality objective. None of the 3 samples exceed the general water quality objective for oxygen saturation (when applied as a single sample maximum). 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. However, there are an insufficient number of samples to make a "use rating" decision. Central Coast Water Board staff require a minimum of 26 samples to make a "use rating" decision of Fully Supporting. 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 the 8 samples exceed the Warm Freshwater Habitat water quality objective 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 11604

LOE ID: | 19912
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Santa Cruz County Environmental Health Monitoring Program (R3_SCCEH) data for Schwann Lake to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Oxygen, Saturation.
Data Reference: | Final Data File used for assessment: Santa Cruz County Environmental Health data 1971-1996
| Final Data File used for assessment: Santa Cruz County Environmental Health data 1997-2006
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: Median values should not fall below 85% saturation as a result of controllable water quality conditions.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Schwann Lake was collected at 1 monitoring site [ 304SCL_SCC - SCHWAN LAKE at MOUTH]
Temporal Representation: | Data was collected over the time period 5/14/1992-5/27/1993.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | This monitoring program has been underway for thirty years, with changes over time to protocols, level of QA, and documentation. In general, QA documentation included with the dataset is minimal. However, data quality appears to be reasonably good.
QAPP Information Reference(s):
LOE ID: | 19852
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 3
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Santa Cruz County Environmental Health Monitoring Program (R3_SCCEH) data for Schwann Lake to determine beneficial use support and results are as follows: 3 of 8 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: | Final Data File used for assessment: Santa Cruz County Environmental Health data 1971-1996
| Final Data File used for assessment: Santa Cruz County Environmental Health data 1997-2006
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Schwann Lake was collected at 1 monitoring site [ 304SCL_SCC - SCHWAN LAKE at MOUTH]
Temporal Representation: | Data was collected over the time period 5/14/1992-10/24/2002.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | This monitoring program has been underway for thirty years, with changes over time to protocols, level of QA, and documentation. In general, QA documentation included with the dataset is minimal. However, data quality appears to be reasonably good.
QAPP Information Reference(s):

DECISION ID | 11606
Pollutant: | Turbidity
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 pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 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. None of the 2 samples exceed the Evaluation Guideline (Sigler et al., 1984) applied to protect for aquatic life beneficial uses. 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. However, there are an insufficient number of samples to make a "use rating" decision. Central Coast Water Board staff require a minimum of 26 samples to make a "use rating" decision of Fully Supporting. 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. None of the 2 samples exceed the Evaluation Guideline (Sigler et al., 1984) applied to protect for aquatic life beneficial uses and the sample size is insufficient to determine with the power and confidence of the Listing Policy if water quality standards are met or exceeded. 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 and the sample size is insufficient to determine with the power and confidence of the Listing Policy if water quality standards are met or exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 11606

LOE ID: | 19384
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Santa Cruz County Environmental Health Monitoring Program (R3_SCCEH) data for Schwann Lake to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Turbidity(NTU).
Data Reference: | Final Data File used for assessment: Santa Cruz County Environmental Health data 1971-1996
| Final Data File used for assessment: Santa Cruz County Environmental Health data 1997-2006
Water Quality Objective/Criterion: | Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: | Sigler et al. (1984) states that turbidities of 25 NTU's or greater caused reduction in juvenile salmonid growth due to interference with their ability to find food.
Guideline Reference: | Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150
Spatial Representation: | Data for this line of evidence for Schwann Lake was collected at 1 monitoring site [ 304SCL_SCC - SCHWAN LAKE at MOUTH]
Temporal Representation: | Data was collected over the time period 10/16/2002-10/24/2002.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | This monitoring program has been underway for thirty years, with changes over time to protocols, level of QA, and documentation. In general, QA documentation included with the dataset is minimal. However, data quality appears to be reasonably good.
QAPP Information Reference(s):

DECISION ID | 11607
Pollutant: | pH
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 pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 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. Two of the 8 samples exceed the Recreation use water quality objectives and none of the 8 samples exceed the Warm Freshwater Habitat water quality objective. 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. However, there are an insufficient number of samples to make a "use rating" decision. Central Coast Water Board staff require a minimum of 26 samples to make a "use rating" decision of Fully Supporting. 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 the 8 samples exceed the Recreation use water quality objectives and none of the 8 samples exceed the Warm Freshwater Habitat water quality objective 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 11607

LOE ID: | 19839
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Santa Cruz County Environmental Health Monitoring Program (R3_SCCEH) data for Schwann Lake to determine beneficial use support and results are as follows: 0 of 8 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: Santa Cruz County Environmental Health data 1971-1996
| Final Data File used for assessment: Santa Cruz County Environmental Health data 1997-2006
Water Quality Objective/Criterion: | Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Schwann Lake was collected at 1 monitoring site [ 304SCL_SCC - SCHWAN LAKE at MOUTH]
Temporal Representation: | Data was collected over the time period 5/14/1992-10/24/2002.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | This monitoring program has been underway for thirty years, with changes over time to protocols, level of QA, and documentation. In general, QA documentation included with the dataset is minimal. However, data quality appears to be reasonably good.
QAPP Information Reference(s):
LOE ID: | 19838
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 8
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Santa Cruz County Environmental Health Monitoring Program (R3_SCCEH) data for Schwann Lake to determine beneficial use support and results are as follows: 2 of 8 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: Santa Cruz County Environmental Health data 1971-1996
| Final Data File used for assessment: Santa Cruz County Environmental Health data 1997-2006
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Schwann Lake was collected at 1 monitoring site [ 304SCL_SCC - SCHWAN LAKE at MOUTH]
Temporal Representation: | Data was collected over the time period 5/14/1992-10/24/2002.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | This monitoring program has been underway for thirty years, with changes over time to protocols, level of QA, and documentation. In general, QA documentation included with the dataset is minimal. However, data quality appears to be reasonably good.
QAPP Information Reference(s):
LOE ID: | 19837
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 8
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Santa Cruz County Environmental Health Monitoring Program (R3_SCCEH) data for Schwann Lake to determine beneficial use support and results are as follows: 2 of 8 samples exceed the criterion for pH.
Data Reference: | Final Data File used for assessment: Santa Cruz County Environmental Health data 1971-1996
| Final Data File used for assessment: Santa Cruz County Environmental Health data 1997-2006
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for water contact recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Schwann Lake was collected at 1 monitoring site [ 304SCL_SCC - SCHWAN LAKE at MOUTH]
Temporal Representation: | Data was collected over the time period 5/14/1992-10/24/2002.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | This monitoring program has been underway for thirty years, with changes over time to protocols, level of QA, and documentation. In general, QA documentation included with the dataset is minimal. However, data quality appears to be reasonably good.
QAPP Information Reference(s):

DECISION ID | 4443
Pollutant: | Escherichia coli (E. Coli)
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: | Natural Sources | Urban Runoff/Storm Sewers
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 sections 2.1 and 3.3 of the Listing Policy. Three lines of evidence are available in the administrative record to assess this pollutant; the placeholder LOE representing the original listing on the Section 303(d) list for pathogens and two LOEs for E. coli. The original listing is being replaced by listings for individual pathogen indicators (E. coli and Fecal Coliform). This decision changes the pathogen listing to a listing for E. coli. Also see individual decision for Fecal Coliform. Based on section 3.3 the site exceeded numeric objectives for conventional pollutants. According to 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 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 the 8 samples exceed the Evaluation Guideline (USEPA Ambient Water Quality Criteria for Bacteria, 1986) as it applies to the Water Contact Recreation beneficial use 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.
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 4443

LOE ID: | 19844
Pollutant: | Escherichia coli (E. Coli)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Santa Cruz County Environmental Health Monitoring Program (R3_SCCEH) data for Schwann Lake to determine beneficial use support and results are as follows: 0 of 8 samples exceed the criterion for Escherichia coli.
Data Reference: | Final Data File used for assessment: Santa Cruz County Environmental Health data 1971-1996
| Final Data File used for assessment: Santa Cruz County Environmental Health data 1997-2006
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 2000/100 ml, nor shall more than ten percent of samples collected during any 30-day period exceed 4000/100 ml. E. coli is a fecal coliform.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Schwann Lake was collected at 1 monitoring site [ 304SCL_SCC - SCHWAN LAKE at MOUTH]
Temporal Representation: | Data was collected over the time period 2/5/2001-2/28/2005.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | This monitoring program has been underway for thirty years, with changes over time to protocols, level of QA, and documentation. In general, QA documentation included with the dataset is minimal. However, data quality appears to be reasonably good.
QAPP Information Reference(s):
LOE ID: | 19843
Pollutant: | Escherichia coli (E. Coli)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 8
Number of Exceedances: | 7
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Santa Cruz County Environmental Health Monitoring Program (R3_SCCEH) data for Schwann Lake to determine beneficial use support and results are as follows: 7 of 8 samples exceed the criterion for Escherichia coli.
Data Reference: | Final Data File used for assessment: Santa Cruz County Environmental Health data 1971-1996
| Final Data File used for assessment: Santa Cruz County Environmental Health data 1997-2006
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 Schwann Lake was collected at 1 monitoring site [ 304SCL_SCC - SCHWAN LAKE at MOUTH]
Temporal Representation: | Data was collected over the time period 2/5/2001-2/28/2005.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | This monitoring program has been underway for thirty years, with changes over time to protocols, level of QA, and documentation. In general, QA documentation included with the dataset is minimal. However, data quality appears to be reasonably good.
QAPP Information Reference(s):
LOE ID: | 4012
Pollutant: | Pathogens
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Not Recorded
Beneficial Use: | Water Contact Recreation
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: | Placeholder reference pre-2006 303(d)
Water Quality Objective/Criterion: | Unspecified
Objective/Criterion Reference: | Placeholder reference pre-2006 303(d)
Evaluation Guideline: | Unspecified
Guideline Reference: | Placeholder reference pre-2006 303(d)
Spatial Representation: | Unspecified
Temporal Representation: | Unspecified
Environmental Conditions: | Unspecified
QAPP Information: | Unspecified
QAPP Information Reference(s):

DECISION ID | 11602
Pollutant: | Fecal Coliform
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 | Urban Runoff/Storm Sewers
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 sections 2.1 and 3.3 of the Listing Policy. Three lines of evidence are available in the administrative record to assess this pollutant; the placeholder LOE representing the original listing on the Section 303(d) list for pathogens and two LOEs for Fecal Coliform. The original listing is being replaced by listings for individual pathogen indicators (E. coli and Fecal Coliform). Based on section 3.3 the site exceeded numeric objectives for conventional pollutants. According to 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 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-two of 30 samples exceeded the Water Contact Recreation 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.
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 11602

LOE ID: | 4012
Pollutant: | Pathogens
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Not Recorded
Beneficial Use: | Water Contact Recreation
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: | Placeholder reference pre-2006 303(d)
Water Quality Objective/Criterion: | Unspecified
Objective/Criterion Reference: | Placeholder reference pre-2006 303(d)
Evaluation Guideline: | Unspecified
Guideline Reference: | Placeholder reference pre-2006 303(d)
Spatial Representation: | Unspecified
Temporal Representation: | Unspecified
Environmental Conditions: | Unspecified
QAPP Information: | Unspecified
QAPP Information Reference(s):
LOE ID: | 18791
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 30
Number of Exceedances: | 22
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Santa Cruz County Environmental Health Monitoring Program (R3_SCCEH) data for Schwann Lake to determine beneficial use support and results are as follows: 22 of 30 samples exceed the criterion for Coliform, Fecal.
Data Reference: | Final Data File used for assessment: Santa Cruz County Environmental Health data 1971-1996
| Final Data File used for assessment: Santa Cruz County Environmental Health data 1997-2006
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for water contact recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 200 MPN/100 ml, nor shall more than ten percent of total samples during any 30-day period exceed 400 MPN/100 ml.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Schwann Lake was collected at 1 monitoring site [ 304SCL_SCC - SCHWAN LAKE at MOUTH]
Temporal Representation: | Data was collected over the time period 2/5/1990-12/16/1991.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | This monitoring program has been underway for thirty years, with changes over time to protocols, level of QA, and documentation. In general, QA documentation included with the dataset is minimal. However, data quality appears to be reasonably good.
QAPP Information Reference(s):
LOE ID: | 18805
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Non-Contact Recreation
Number of Samples: | 30
Number of Exceedances: | 1
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Santa Cruz County Environmental Health Monitoring Program (R3_SCCEH) data for Schwann Lake to determine beneficial use support and results are as follows: 1 of 30 samples exceed the criterion for Coliform, Fecal.
Data Reference: | Final Data File used for assessment: Santa Cruz County Environmental Health data 1971-1996
| Final Data File used for assessment: Santa Cruz County Environmental Health data 1997-2006
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 2000/100 ml, nor shall more than ten percent of samples collected during any 30-day period exceed 4000/100 ml.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Schwann Lake was collected at 1 monitoring site [ 304SCL_SCC - SCHWAN LAKE at MOUTH]
Temporal Representation: | Data was collected over the time period 2/5/1990-12/16/1991.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | This monitoring program has been underway for thirty years, with changes over time to protocols, level of QA, and documentation. In general, QA documentation included with the dataset is minimal. However, data quality appears to be reasonably good.
QAPP Information Reference(s):

DECISION ID | 11605
Pollutant: | Total Coliform
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 | Urban Runoff/Storm Sewers
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 sections 2.1 and 3.3 of the Listing Policy. On line of evidence is available in the administrative record to assess this pollutant. Based on section 3.3 the site exceeded numeric objectives for conventional pollutants. According to 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 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 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.
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 11605

LOE ID: | 19762
Pollutant: | Total Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Shellfish Harvesting
Number of Samples: | 6
Number of Exceedances: | 6
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | Central Coast Regional Board Staff assessed Santa Cruz County Environmental Health Monitoring Program (R3_SCCEH) data for Schwann Lake to determine beneficial use support and results are as follows: 6 of 6 samples exceed the criterion for Coliform, Total.
Data Reference: | Final Data File used for assessment: Santa Cruz County Environmental Health data 1971-1996
| Final Data File used for assessment: Santa Cruz County Environmental Health data 1997-2006
Water Quality Objective/Criterion: | The Water Quality Control Plan, Central Coast Basin Shellfish Harvesting objective (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries (page III-12)) states the following: At all areas where shellfish may be harvested for human consumption, the median total coliform concentration throughout the water column for any 30-day period shall not exceed 70 MPN/100mL, not shall more than ten percent of the samples collected during any 30-day period exceed 230 MPN/100mL for a five tube decimal dilution test.
Objective/Criterion Reference: | Water Quality Control Plan Central Coast Region (R3) Basin Plan
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Data for this line of evidence for Schwann Lake was collected at 1 monitoring site [ 304SCL_SCC - SCHWAN LAKE at MOUTH]
Temporal Representation: | Data was collected over the time period 2/5/2001-2/28/2005.
Environmental Conditions: | Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: | This monitoring program has been underway for thirty years, with changes over time to protocols, level of QA, and documentation. In general, QA documentation included with the dataset is minimal. However, data quality appears to be reasonably good.
QAPP Information Reference(s):

DECISION ID | 4442
Pollutant: | Nutrients
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: | Nonpoint Source
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | 303(d) listing decisions made prior to 2006 were not held in an assessment database. The Regional Boards will update this decision when new data and information become available and are assessed.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The decision has not changed.
SWRCB Board Decision / Staff Recommendation: | N/A
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4442

LOE ID: | 4011
Pollutant: | Nutrients
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Not Recorded
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: | Placeholder reference pre-2006 303(d)
Water Quality Objective/Criterion: | Unspecified
Objective/Criterion Reference: | Placeholder reference pre-2006 303(d)
Evaluation Guideline: | Unspecified
Guideline Reference: | Placeholder reference pre-2006 303(d)
Spatial Representation: | Unspecified
Temporal Representation: | Unspecified
Environmental Conditions: | Unspecified
QAPP Information: | Unspecified
QAPP Information Reference(s):