| Water Body Name: | Newport Slough |
| Water Body ID: | CAR8011100020011107123409 |
| Water Body Type: | River & Stream |
DECISION ID |
149165 |
Region 8 |
Newport Slough |
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| Pollutant: | Indicator Bacteria |
| Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list)(2018) |
| Revision Status | Revised |
| Sources: | A Source Unknown |
| Expected TMDL Completion Date: | 2037 |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | This pollutant is being considered for removal from the CWA section 303(d) List under sections 4.2 and 4.3 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status. 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. Four (4) lines of evidence are available in the administrative record to assess this pollutant for the REC-1 beneficial use. One hundred and eighteen (118) of 649 samples exceed the 6- week Enterococcus Geomean Objective. 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 on the CWA 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. One hundred and eighteen (118) of 649 samples exceed the 6- week Enterococcus Geomean Objective and this exceeds the allowable frequency in Table 4.2 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. 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. These historical lines of evidence are: 5 LOEs for Total Coliform (26098, 26101, 81973, 81972, 81971), 5 LOEs for Fecal Coliform (26097, 81969, 81970, 26100, 81968), 5 LOEs for Enterococcus (81965, 81967, 81966, 26096, 26099) and will be retired. 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. |
| 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: | |
| State Board Decision Recommendation: | After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board. |
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| LOE ID: | 300638 | ||||
| Pollutant: | Enterococcus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | STV | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 99 | ||||
| Number of Exceedances: | 20 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed BeachWatch_Orange County data for Newport Slough to determine beneficial use support and the results are as follows: 20 of the 99 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: | Field, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is 1 ppth or higher 95 percent or more of the time applies a Statistical Threshold Value to enterococcus of 110 cfu/100 mL, not to be exceeded by more than 10 percent of samples collected within in a calendar month. (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): BNS01 (BNS01-Newport Slough, Orange). | ||||
| Temporal Representation: | The samples were collected between the days of 2010-09-07 and 2020-10-15 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | State Board Staff. 2021. QAPP Reference for Beach Watch Program. | ||||
| QAPP Information Reference(s): | QAPP Reference for Beach Watch Program | ||||
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| LOE ID: | 300684 | ||||
| Pollutant: | Enterococcus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | GeoMean | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 340 | ||||
| Number of Exceedances: | 76 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed BeachWatch_Orange County data for Newport Slough to determine beneficial use support and the results are as follows: 76 of the 340 samples exceeded the geomean water quality threshold for Enterococcus. This is a six week rolling geomean that is calculated weekly. | ||||
| Data Reference: | Field, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is 1 ppth or higher 95 percent or more of the time applies a six-week rolling geomean to enterococcus, not to exceed 30 cfu/100mL. (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): BNS02 (BNS02-Newport Slough, Orange). | ||||
| Temporal Representation: | The samples were collected between the days of 2010-08-31 and 2020-10-15 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | State Board Staff. 2021. QAPP Reference for Beach Watch Program. | ||||
| QAPP Information Reference(s): | QAPP Reference for Beach Watch Program | ||||
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| LOE ID: | 300629 | ||||
| Pollutant: | Enterococcus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | STV | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 106 | ||||
| Number of Exceedances: | 30 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed BeachWatch_Orange County data for Newport Slough to determine beneficial use support and the results are as follows: 30 of the 106 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: | Field, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is 1 ppth or higher 95 percent or more of the time applies a Statistical Threshold Value to enterococcus of 110 cfu/100 mL, not to be exceeded by more than 10 percent of samples collected within in a calendar month. (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): BNS02 (BNS02-Newport Slough, Orange). | ||||
| Temporal Representation: | The samples were collected between the days of 2010-08-31 and 2020-10-15 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | State Board Staff. 2021. QAPP Reference for Beach Watch Program. | ||||
| QAPP Information Reference(s): | QAPP Reference for Beach Watch Program | ||||
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| LOE ID: | 300687 | ||||
| Pollutant: | Enterococcus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | GeoMean | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 309 | ||||
| Number of Exceedances: | 42 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed BeachWatch_Orange County data for Newport Slough to determine beneficial use support and the results are as follows: 42 of the 309 samples exceeded the geomean water quality threshold for Enterococcus. This is a six week rolling geomean that is calculated weekly. | ||||
| Data Reference: | Field, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is 1 ppth or higher 95 percent or more of the time applies a six-week rolling geomean to enterococcus, not to exceed 30 cfu/100mL. (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): BNS01 (BNS01-Newport Slough, Orange). | ||||
| Temporal Representation: | The samples were collected between the days of 2010-09-07 and 2020-10-15 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | State Board Staff. 2021. QAPP Reference for Beach Watch Program. | ||||
| QAPP Information Reference(s): | QAPP Reference for Beach Watch Program | ||||