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DECISION ID |
12615 |
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| 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: |
New Decision |
| Revision Status |
Revised |
| Impairment from Pollutant or Pollution: |
Pollutant |
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| 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 (1) line of evidence is available in the administrative record to assess this pollutant. Thirty-seven (37) of the samples exceed the water quality objective.
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. Thirty-seven (37) of forty-three (43) samples exceed the EPA's 1986 Recommended Water Quality Criteria for Bacteria 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. |
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| RWQCB Board Decision / Staff Recommendation: |
After review of the available data and information, RWQCB staff concludes that though this water body's E. coli data exceeds EPA's Recommended Criteria it is not appropriate at this time to list it as impaired. There is a Storm Water Quality Task Force working on determining the appropriate indicators and the appropriate criteria to protect body contact recreation in fresh waters. Listing this waterbody for E. coli would circumvent a much needed process that is currently underway. Regional Board staff actively participate in this process with the SWQTF and will recommend review of this data in the 2010 listing cycle by when the appropriate criteria and indicators will have been developed. |
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| SWRCB Board Decision / Staff Recommendation: |
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| USEPA Decision: |
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| LOE ID: |
21464 |
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| Pollutant: |
Escherichia coli (E. Coli) |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
| Aquatic Life Use: |
Warm Freshwater Habitat |
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| Number of Samples: |
43 |
| Number of Exceedances: |
37 |
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| Data and Information Type: |
PATHOGEN MONITORING |
| Data Used to Assess Water Quality: |
Of the 43 samples taken, 37 exceeded EPA's recommended single sample standard. The exceedances occurred at both of the stations: Borrego1 and Borrego 2. |
| Data Reference: |
Orange County Coast Keeper Coastal Watersheds Project |
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| Water Quality Objective/Criterion: |
USEPA Recommended Ambient Water Quality Criteria for Bacteria -1986: E. coli: log mean less than 126 organisms/100 mL based on five or more samples per 30–day period, and not more than 10% of the samples exceed 235 organisms/100mL for any 30 day period. |
| Objective/Criterion Reference: |
Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002 |
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| Evaluation Guideline: |
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| Guideline Reference: |
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| Spatial Representation: |
The samples were taken at Borrego1 and Borrego 2. Borrego 1 is Located in Foothill Ranch in the upper Borrego Channel on Town Center Dr.
Borego 2 is Located in Irvine in the lower Borrego Channel on Barranca Pkwy next to the train station . |
| Temporal Representation: |
The samples were collected monthly starting on March 11, 2004 through March 29, 2006. |
| Environmental Conditions: |
Staff is not aware of any special conditions that might effect interpretation of the data. |
| QAPP Information: |
The data's quality is deemed appropriate because it was obtained under the auspices of a QAPP approved by the Regional Board. |
| QAPP Information Reference(s): |
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DECISION ID |
12611 |
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| Pollutant: |
Ammonia (Unionized) |
| Final Listing Decision: |
List on 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: |
New Decision |
| Revision Status |
Revised |
| Sources: |
Other Urban Runoff | Storm sewers | Surface Runoff | Unknown Nonpoint Source |
| Expected TMDL Completion Date: |
2022 |
| Impairment from Pollutant or Pollution: |
Pollutant |
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| Weight of Evidence: |
This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.
One (1) line of evidence is available in the administrative record to assess this pollutant. Five (5) of the samples exceed the water quality objective.
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. Five (5) of seven (7) samples exceed the Basin Plan's Objective and this exceeds the allowable frequency listed in Table 3.1 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. |
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| 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. This listing is solely for the downstream reach of Borrego Creek because the exceedances are mainly in the downstream reach of the creek. It is not appropriate to list the entire reach when the exceedances occur mainly in one portion of the creek. |
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| SWRCB Board Decision / Staff Recommendation: |
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| USEPA Decision: |
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Lines of Evidence (LOEs) for Decision ID 12611 |
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| LOE ID: |
21458 |
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| Pollutant: |
Ammonia (Unionized) |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
| Aquatic Life Use: |
Warm Freshwater Habitat |
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| Number of Samples: |
7 |
| Number of Exceedances: |
5 |
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| Data and Information Type: |
PHYSICAL/CHEMICAL MONITORING |
| Data Used to Assess Water Quality: |
Of the 7 samples collected, 5 exceeded the Basin Plan Objective. The exceedance occurred at sampling location bor2 |
| Data Reference: |
Orange County Coast Keeper Coastal Watersheds Project |
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| Water Quality Objective/Criterion: |
Un-ionized ammonia Basin Plan Objective: The objective varies according to the temperature of the water being sampled and ranged during the sampling period as follows: 0.20 mg/l - 0.49 mg/l |
| Objective/Criterion Reference: |
Water Quality Control Plan-Santa Ana Region |
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| Evaluation Guideline: |
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| Guideline Reference: |
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| Spatial Representation: |
The samples were collected at one station: bor2. Borego 2 is Located in Irvine in the lower Borrego Channel on Barranca pkwy next to the train station. |
| Temporal Representation: |
The samples were collected monthly starting on 5/14/2004 through 3/25/2005. |
| Environmental Conditions: |
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| QAPP Information: |
The data's quality is deemed acceptable because it was collected under the auspices of a Regional Board staff's approved quality assurance plan. |
| QAPP Information Reference(s): |