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DECISION ID |
4154 |
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| Pollutant: |
Ammonia |
| Final Listing Decision: |
Delist from 303(d) list (being addressed by USEPA approved TMDL) |
| Last Listing Cycle's Final Listing Decision: |
List on 303(d) list (being addressed by USEPA approved TMDL)(2006) |
| Revision Status |
Revised |
| Reason for Delisting: |
State determines water quality standard is being met |
| TMDL Name: |
Los Angeles River Nitrogen |
| TMDL Project Code: |
229 |
| Date TMDL Approved by USEPA: |
03/18/2004 |
| Impairment from Pollutant or Pollution: |
Pollutant |
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| Weight of Evidence: |
This pollutant is being considered for removal from the section 303(d) list under section 4.1 of the Listing Policy. Under this section 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.
Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for removing this water segment-pollutant combination from the section 303(d) list.
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. Zero of 301 samples exceeded the Basin Plan pH and temperature dependent acute ammonia criteria and zero of 100 samples exceeded the Basin Plan pH and temperature dependent chronic ammonia criteria use and this does not exceed the allowable frequency listed in Table 4.1 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. |
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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 removed from the section 303(d) list because applicable water quality standards for the pollutant 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: |
2483 |
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| Pollutant: |
Ammonia |
| LOE Subgroup: |
Narrative Description Data |
| Matrix: |
Not Specified |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
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| Number of Samples: |
0 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
Not Specified |
| Data Used to Assess Water Quality: |
An alternative enforceable program is in place that will address ammonia water quality standards exceedances for this reach. In June 1995, the seven water reclamation plants discharging in the San Gabriel River and Santa Clara River watersheds received NPDES permits containing requirements regarding compliance with the Basin Plan water quality objectives for ammonia. In accordance with these permits, the Los Angeles County Sanitation Districts have been pursuing the addition of nitrification and denitrification facilities at each of these plants to comply with the ammonia objectives. By June 2003, it is expected that these new facilities will be operational and ammonia will be drastically reduced. Research facility operation shows that the monthly average ammonia concentration will fully comply with the chronic ammonia objective. Objective is expected to be applicable in June 2003.
It is probable that the majority of ammonia discharged to this water body was contributed by POTWs. Information in the record indicates that the majority (over 95%) of the ammonia in the Los Angeles River was contributed by POTWs. Also, it is probable that the contribution in the San Gabriel River watershed is dominated by contributions from POTWs as well. Generally, concentrations of ammonia upstream of the treatment plants are much lower than downstream concentrations (up to an order of magnitude difference). |
| Data Reference: |
Placeholder reference 2006 303(d) |
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| Water Quality Objective/Criterion: |
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| Objective/Criterion Reference: |
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| Evaluation Guideline: |
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| Guideline Reference: |
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| Spatial Representation: |
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| Temporal Representation: |
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| Environmental Conditions: |
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| QAPP Information: |
QA Info Missing |
| QAPP Information Reference(s): |
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| LOE ID: |
2485 |
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| Pollutant: |
Ammonia |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
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| Number of Samples: |
36 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
PHYSICAL/CHEMICAL MONITORING |
| Data Used to Assess Water Quality: |
Based on 30-day average concentrations of ammonia, no samples of 36 total samples exceed the ammonia objective. Ambient measurements of pH and temperature (30-day averages) were used to calculate the water quality objective. (LACSD, 2004b). |
| Data Reference: |
Placeholder reference 2006 303(d) |
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| Water Quality Objective/Criterion: |
In order to protect aquatic life, ammonia concentrations in inland surface waters characteristic of freshwater shall not exceed the values calculated for the appropriate instream conditions [both pH and temperature] shown in Tables 3-1 to 3-3 [in the Basin Plan] (per U.S. EPA's most recent criteria guidance document, '1999 Update of Ambient Water Quality Criteria for Ammonia'). |
| Objective/Criterion Reference: |
Placeholder reference 2006 303(d) |
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| Evaluation Guideline: |
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| Guideline Reference: |
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| Spatial Representation: |
Three stations. |
| Temporal Representation: |
Samples were collected from February 2001 through November 2004. New management practices were begun at the beginning of this period and may have resulted in a change in water quality. Water quality measurements collected before the implementation of management measures were not considered representative of current conditions. |
| Environmental Conditions: |
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| QAPP Information: |
NPDES quality assurance. |
| QAPP Information Reference(s): |
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| LOE ID: |
28216 |
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| Pollutant: |
Ammonia |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
Total |
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| Beneficial Use: |
Warm Freshwater Habitat |
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| Number of Samples: |
301 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
Fixed station physical/chemical (conventional plus toxic pollutants) |
| Data Used to Assess Water Quality: |
Zero of 301 samples exceeded the acute criteria for ammonia and one out of 100 samples exceeded the chronic criteria. Samples are from the County Sanitation Districts of Los Angeles, Whittier Narrows Water Reclamation Plant (WNRP) -Monitoring Reports 2003-2007 |
| Data Reference: |
Whittier Narrows Water Reclamation Plant (WNRP) -Monitoring Reports 2003-2007 |
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| Water Quality Objective/Criterion: |
The acute (1-hour average) and chronic (4-day average) concentrations for ammonia are the highest concentrations of to which aquatic life can be exposed for a short period and an extended period of time, respectively, without deleterious effects applicable to protect aquatic life Beneficial Uses. These criteria are pH and temperature dependent and vary accordingly. The ammonia objectives and the pH and temperature dependent formulas are found in Attachment A of Regional Board Resolution No. 2002-011. |
| Objective/Criterion Reference: |
Water Quality Control Plan Los Angeles Region R4 Basin Plan |
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Basin Plan Amendments to the Water Quality Control Plan Los Angeles Region R4 Basin Plan as of 02/02/2009 |
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| Evaluation Guideline: |
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| Guideline Reference: |
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| Spatial Representation: |
Two receiving water monitoring stations: RD located 1000 ft upstream from San Gabriel Boulevard, downstream of WNRP Discharge point 004, and RD-1 100ft upstream of WNRP Discharge point 004. |
| Temporal Representation: |
Weekly and monthly samples collected and analyzed from October 2003 to January 2008. |
| Environmental Conditions: |
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| QAPP Information: |
Data collected for compliance with NPDES Permit No. CAS-004001 Monitoring and Reporting Programs. |
| QAPP Information Reference(s): |
Monitoring and Reporting Program - CI 6948 for order no. 01-182
NPDES No. CAS004001 Municipal Storm Water and Urban Runoff Discharges within the County of Los Angeles, and the incorporated cities, except the City of
Long Beach
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