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DECISION ID |
16576 |
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| Pollutant: |
Ammonia (Unionized) |
| 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 3.1 of the Listing Policy. Under section 3.1 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. Two 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 against 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. Two of 34 samples exceeded the Basin Plan Objective and this does not exceed 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 not be placed on the section 303(d) list because applicable water quality standards are not being exceeded. |
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| SWRCB Board Decision / Staff Recommendation: |
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| USEPA Decision: |
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| LOE ID: |
28433 |
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| Pollutant: |
Ammonia (Unionized) |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
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| Number of Samples: |
34 |
| Number of Exceedances: |
2 |
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| Data and Information Type: |
PHYSICAL/CHEMICAL MONITORING |
| Data Used to Assess Water Quality: |
Of the 34 samples collected, two exceeded the Basin Plan Objective. The exceedances took place at station bor 1. |
| 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 - 0.44 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: bor 1 located in Foothill Ranch in the upper Borrego Channel on Town Center Dr. |
| Temporal Representation: |
The samples were collected monthly starting on 3/11/2004 through 3/29/2006. |
| 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): |