Draft California 2020 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 9 - San Diego Region

Water Body Name:	Mission Bay Shoreline, at North Cove Beach at Vacation Isle
Water Body ID:	CAC9075200020120705142708
Water Body Type:	Coastal & Bay Shoreline


DECISION ID	127899	Region 9
Mission Bay Shoreline, at North Cove Beach at Vacation Isle

Pollutant:	Indicator Bacteria
Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Sources:	A Source Unknown
Reason for Delisting:	Applicable WQS attained; due to change in WQS
Expected TMDL Completion Date:	2033
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the section 303(d) list under section 4.3 of the Listing Policy. Under section 4.3 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Thirty-eight of the 185 samples exceed the GM threshold for Enterococci. 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 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. Thirty-eight of the 185 samples exceeded the Enterococci water quality threshold for the protection of REC-1, 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 not met. The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the “ISWEBE Plan”) contains two bacteria water quality objectives applicable to the REC-1 beneficial use, which were adopted on August 7, 2018. Because the salinity level of this waterbody is greater than 1 part per thousand more than 5 percent of the time, the enterococci bacteria objective applies. Therefore, this waterbody is being considered for placement on or removal from the CWA section 303(d) List under section 3.3 or 4.3 of the Listing Policy, as applicable, using the enterococci objective. In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Indicator bacteria (total coliform, fecal coliform, E. coli, enterococci) populations may fluctuate substantially on a daily, seasonal, or yearly basis. Lacking constant inputs, they do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of indicator bacteria in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Additionally, water quality conditions in waterbodies may change as a result of management actions that have been implemented to address bacteria. Unrepresentative data may result in incorrectly placing or not placing a water body segment on the list, which could result in the unnecessary expenditure of public resources or missing a human health problem. Historic lines of evidence for data collected prior to 2010 were evaluated pursuant to these considerations and were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy. For enterococci data, Listing Policy sections 3.3 and 4.3 instructs to use the binomial distribution table in sections 3.2 and 4.2, as applicable. To use the binomial table that uses a four percent exceedance frequency, the data must be collected from coastal beaches or inland surface waters from April 1 through October 31 only, and where collected from inland waters from April 1 through October 31 only, bacterial measurements must be indicative of human fecal matter, and there is substantial human contact in the waterbody. No fecal coliform data are used in this assessment because the fecal coliform water quality objective was superseded and is no longer used as the basis of any 303(d) List decision for water contact recreation.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:	The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the “ISWEBE Plan”) contains two bacteria water quality objectives applicable to the REC-1 beneficial use, which were adopted on August 7, 2018. Because the salinity level of this waterbody is greater than 1 part per thousand more than 5 percent of the time, the enterococci bacteria objective applies. Therefore, this waterbody is being considered for placement on or removal from the CWA section 303(d) List under section 3.3 or 4.3 of the Listing Policy, as applicable, using the enterococci objective. In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Indicator bacteria (total coliform, fecal coliform, E. coli, enterococci) populations may fluctuate substantially on a daily, seasonal, or yearly basis. Lacking constant inputs, they do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of indicator bacteria in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Additionally, water quality conditions in waterbodies may change as a result of management actions that have been implemented to address bacteria. Unrepresentative data may result in incorrectly placing or not placing a water body segment on the list, which could result in the unnecessary expenditure of public resources or missing a human health problem. Historic lines of evidence for data collected prior to 2010 were evaluated pursuant to these considerations and were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy. For enterococci data, Listing Policy sections 3.3 and 4.3 instructs to use the binomial distribution table in sections 3.2 and 4.2, as applicable. To use the binomial table that uses a four percent exceedance frequency, the data must be collected from coastal beaches or inland surface waters from April 1 through October 31 only, and where collected from inland waters from April 1 through October 31 only, bacterial measurements must be indicative of human fecal matter, and there is substantial human contact in the waterbody. No fecal coliform data are used in this assessment because the fecal coliform water quality objective was superseded and is no longer used as the basis of any 303(d) List decision for water contact recreation.

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 127899, Indicator Bacteria	Region 9
Mission Bay Shoreline, at North Cove Beach at Vacation Isle

LOE ID:

77609

Pollutant:

Total Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Shellfish Harvesting

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Fifty-seven of the 89 samples exceeded the objective of 70 mpn/100ml applied as a rolling 30 day geomean.

Data Reference:

Data for Region 9 Beach Watch.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the San Diego Basin states that 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 per 100 mL. Staff applied the objective as a rolling 30 day geometric mean consistent with other state bacteria objectives and with guidance from the National Shellfish Sanitation Program from which the objectives were taken.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at Mission Bay Shoreline, at Fiesta Island northwest shore.

Temporal Representation:

The samples were collected from April 2008 to August 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 127899, Indicator Bacteria	Region 9
Mission Bay Shoreline, at North Cove Beach at Vacation Isle

LOE ID:

74354

Pollutant:

Total Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Shellfish Harvesting

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed BW data for Mission Bay Shoreline, at North Cove Beach at Vacation Isle to determine beneficial use support and results are as follows: 23 of 98 samples exceed the criterion for Coliform, Total.

Data Reference:

Data for Region 9 Beach Watch.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan (Basin Plan 2011)states the following: At all areas where shellfish may be harvested for human consumption, ten percent of the samples collected during any 30-day period shall not exceed 230 MPN/100mL.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mission Bay Shoreline, at North Cove Beach at Vacation Isle was collected at 1 monitoring site [ North Cove beach]

Temporal Representation:

Data was collected over the time period April 2008 to August 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):

Line of Evidence (LOE) for Decision ID 127899, Indicator Bacteria	Region 9
Mission Bay Shoreline, at North Cove Beach at Vacation Isle

LOE ID:

220563

Pollutant:

Enterococcus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Mission Bay Shoreline, at North Cove Beach at Vacation Isle to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the geomean water quality threshold for Enterococcus. This is a six week rolling geomean that is calculated weekly. This data is for an AB411 beach. This LOE specifically corresponds with dry weather samples and only includes samples collected between April 1 and October 31 of each year.

Data Reference:

Coastal Counties in Region 9 including: Orange, San Diego, and Los Angeles counties.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective to protect the REC-1 beneficial for all saline waters, is a geometric mean (GM) of Enterococci not to exceed 30 cfu/100 mL. The waterbody GM shall not be greater than the applicable GM magnitude in any six-week interval, calculated weekly (ISWEBE 2018).

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): MB-200

Temporal Representation:

The samples were collected between the days of 2011-06-14 and 2011-08-30 .

Environmental Conditions:

QAPP Information:

QAPP for San Diego County Beachwatch data

QAPP Information Reference(s):

QAPP for San Diego County Beachwatch data for the 2020 Integrated Report.

Line of Evidence (LOE) for Decision ID 127899, Indicator Bacteria	Region 9
Mission Bay Shoreline, at North Cove Beach at Vacation Isle

LOE ID:

219976

Pollutant:

Enterococcus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

184

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Mission Bay Shoreline, at North Cove Beach at Vacation Isle to determine beneficial use support and the results are as follows: 38 of the 184 samples exceeded the geomean water quality threshold for Enterococcus. This is a six week rolling geomean that is calculated weekly.

Data Reference:

Coastal Counties in Region 9 including: Orange, San Diego, and Los Angeles counties.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): MB-205

Temporal Representation:

The samples were collected between the days of 2010-08-31 and 2019-06-12 .

Environmental Conditions:

QAPP Information:

QAPP for San Diego County Beachwatch data

QAPP Information Reference(s):

QAPP for San Diego County Beachwatch data for the 2020 Integrated Report.

Line of Evidence (LOE) for Decision ID 127899, Indicator Bacteria	Region 9
Mission Bay Shoreline, at North Cove Beach at Vacation Isle

LOE ID:

219776

Pollutant:

Total Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Shellfish Harvesting

Number of Samples:

287

Number of Exceedances:

105

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Mission Bay Shoreline, at North Cove Beach at Vacation Isle to determine beneficial use support and the results are as follows: 105 of the 287 samples exceeded the water quality threshold for Coliform, Total. The water quality threshold is based on a 10% exceedance rate that is calculated for a 30-Day peroid.

Data Reference:

Coastal Counties in Region 9 including: Orange, San Diego, and Los Angeles counties.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The San Diego Basin Plan states that not more than 10 percent of the total coliform samples shall exceed 230 per 100 mL where the shellfish beneficial use applies.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): MB-205

Temporal Representation:

The samples were collected between the days of 2010-08-31 and 2019-06-12 .

Environmental Conditions:

QAPP Information:

QAPP for San Diego County Beachwatch data

QAPP Information Reference(s):

QAPP for San Diego County Beachwatch data for the 2020 Integrated Report.

Line of Evidence (LOE) for Decision ID 127899, Indicator Bacteria	Region 9
Mission Bay Shoreline, at North Cove Beach at Vacation Isle

LOE ID:

220566

Pollutant:

Enterococcus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Mission Bay Shoreline, at North Cove Beach at Vacation Isle to determine beneficial use support and the results are as follows: 0 of the 2 samples exceeded the Statistical Threshold Value (STV) water quality threshold for Enterococcus. The STV is based on a 10% exceedance rate that is calculated monthly. This data is for an AB411 beach. This LOE specifically corresponds with dry weather samples and only includes samples collected between April 1 and October 31 of each year.

Data Reference:

Coastal Counties in Region 9 including: Orange, San Diego, and Los Angeles counties.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective to protect the REC-1 beneficial for all saline waters, is a Statistical Threshold Value (STV) of Enterococci of 110 cfu/100 mL. The applicable STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month, calculated in a static manner (ISWEBE 2018).

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): MB-200

Temporal Representation:

The samples were collected between the days of 2011-06-14 and 2011-08-30 .

Environmental Conditions:

QAPP Information:

QAPP for San Diego County Beachwatch data

QAPP Information Reference(s):

QAPP for San Diego County Beachwatch data for the 2020 Integrated Report.

Line of Evidence (LOE) for Decision ID 127899, Indicator Bacteria	Region 9
Mission Bay Shoreline, at North Cove Beach at Vacation Isle

LOE ID:

220588

Pollutant:

Total Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Shellfish Harvesting

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Mission Bay Shoreline, at North Cove Beach at Vacation Isle to determine beneficial use support and the results are as follows: 3 of the 7 samples exceeded the water quality threshold for Coliform, Total. The water quality threshold for shellfish is based on the median concentration of Total Coliform at each station, and is calculated as a 30-day rolling median.

Data Reference:

Coastal Counties in Region 9 including: Orange, San Diego, and Los Angeles counties.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The San Diego Region Basin Plan states that the median total coliform density shall not exceed 70 per 100 mL where the shellfish beneficial use applies.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): MB-200

Temporal Representation:

The samples were collected between the days of 2011-06-14 and 2011-08-30 .

Environmental Conditions:

QAPP Information:

QAPP for San Diego County Beachwatch data

QAPP Information Reference(s):

QAPP for San Diego County Beachwatch data for the 2020 Integrated Report.

Line of Evidence (LOE) for Decision ID 127899, Indicator Bacteria	Region 9
Mission Bay Shoreline, at North Cove Beach at Vacation Isle

LOE ID:

220166

Pollutant:

Total Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Shellfish Harvesting

Number of Samples:

287

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Mission Bay Shoreline, at North Cove Beach at Vacation Isle to determine beneficial use support and the results are as follows: 72 of the 287 samples exceeded the water quality threshold for Coliform, Total. The water quality threshold for shellfish is based on the median concentration of Total Coliform at each station, and is calculated as a 30-day rolling median.

Data Reference:

Coastal Counties in Region 9 including: Orange, San Diego, and Los Angeles counties.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The San Diego Region Basin Plan states that the median total coliform density shall not exceed 70 per 100 mL where the shellfish beneficial use applies.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): MB-205

Temporal Representation:

The samples were collected between the days of 2010-08-31 and 2019-06-12 .

Environmental Conditions:

QAPP Information:

QAPP for San Diego County Beachwatch data

QAPP Information Reference(s):

QAPP for San Diego County Beachwatch data for the 2020 Integrated Report.

Line of Evidence (LOE) for Decision ID 127899, Indicator Bacteria	Region 9
Mission Bay Shoreline, at North Cove Beach at Vacation Isle

LOE ID:

220584

Pollutant:

Total Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Shellfish Harvesting

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Mission Bay Shoreline, at North Cove Beach at Vacation Isle to determine beneficial use support and the results are as follows: 5 of the 7 samples exceeded the water quality threshold for Coliform, Total. The water quality threshold is based on a 10% exceedance rate that is calculated for a 30-Day peroid.

Data Reference:

Coastal Counties in Region 9 including: Orange, San Diego, and Los Angeles counties.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The San Diego Basin Plan states that not more than 10 percent of the total coliform samples shall exceed 230 per 100 mL where the shellfish beneficial use applies.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): MB-200

Temporal Representation:

The samples were collected between the days of 2011-06-14 and 2011-08-30 .

Environmental Conditions:

QAPP Information:

QAPP for San Diego County Beachwatch data

QAPP Information Reference(s):

QAPP for San Diego County Beachwatch data for the 2020 Integrated Report.

Line of Evidence (LOE) for Decision ID 127899, Indicator Bacteria	Region 9
Mission Bay Shoreline, at North Cove Beach at Vacation Isle

LOE ID:

220365

Pollutant:

Enterococcus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Mission Bay Shoreline, at North Cove Beach at Vacation Isle to determine beneficial use support and the results are as follows: 24 of the 74 samples exceeded the Statistical Threshold Value (STV) water quality threshold for Enterococcus. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

Coastal Counties in Region 9 including: Orange, San Diego, and Los Angeles counties.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): MB-205

Temporal Representation:

The samples were collected between the days of 2010-08-31 and 2019-06-12 .

Environmental Conditions:

QAPP Information:

QAPP for San Diego County Beachwatch data

QAPP Information Reference(s):

QAPP for San Diego County Beachwatch data for the 2020 Integrated Report.