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DECISION ID |
16697 |
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| Pollutant: |
Nitrogen |
| 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 line of evidence is available in the administrative record to assess this pollutant. Four of the 4 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. Four of the 4 samples exceeded the Basin Plan objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy (not enough samples were collected).
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 it cannot be determined if 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: |
26189 |
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| Pollutant: |
Nitrogen |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
Total |
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| Beneficial Use: |
Warm Freshwater Habitat |
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| Number of Samples: |
4 |
| Number of Exceedances: |
4 |
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| Data and Information Type: |
Fixed station physical/chemical (conventional plus toxic pollutants) |
| Data Used to Assess Water Quality: |
Four of four samples collected at Los Coches Creek station (907SDLCO2) from May 2004 to April 2005 showed excessive nitrogen concentrations (SWAMP, 2007). |
| Data Reference: |
Monitoring data for Region 9 |
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| Water Quality Objective/Criterion: |
Water bodies shall not contain biostimulatory substances in concentrations that promote aquatic growth to the extent that such growths cause nuisance or adversely affect beneficial uses (RWQCB, 2007).
A desired goal in order to prevent plant nuisance in streams and other flowing waters appears to be 0.1 mg/L total phosphorus, P. These values are not to be exceeded more than 10% of the time unless studies of the specific water body in question clearly show that water quality objective changes are permissible and changes are approved by the Regional Board. Analogous threshold values have not been set for nitrogen compounds; however, natural ratios of nitrogen to phosphorus are to be determined by surveillance and monitoring and upheld. If data are lacking, a ratio of N:P = 10:1, on a weight to weight basis shall be used (RWQCB, 2007). |
| Objective/Criterion Reference: |
Water Quality Control Plan for the San Diego Basin (9). |
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| Evaluation Guideline: |
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| Guideline Reference: |
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| Spatial Representation: |
Water samples were collected at Los Coches Creek station 2 (907SDLCO2). |
| Temporal Representation: |
Samples were collected in May 2004, September 2004, February 2005, and April 2005. |
| Environmental Conditions: |
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| QAPP Information: |
Quality control for the chemical analysis portion of this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program. |
| QAPP Information Reference(s): |
2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA. |
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DECISION ID |
16698 |
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| Pollutant: |
Phosphorus |
| 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 line of evidence is available in the administrative record to assess this pollutant. Two of the 4 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 the 4 samples exceeded the Basin Plan objective and this does not exceed 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 the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded (not enough samples). |
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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 16698 |
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| LOE ID: |
26190 |
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| Pollutant: |
Phosphorus |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
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| Number of Samples: |
4 |
| Number of Exceedances: |
2 |
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| Data and Information Type: |
Fixed station physical/chemical (conventional plus toxic pollutants) |
| Data Used to Assess Water Quality: |
Two of four samples collected at Los Coches Creek station 2(907SDLCO2) from May 2004 to April 2005 showed excessive phosphorus concentrations (SWAMP, 2007). |
| Data Reference: |
Monitoring data for Region 9 |
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| Water Quality Objective/Criterion: |
As described in San Diego Basin Plan; inland surface waters, bays and estuaries and coastal lagoon waters shall not contain biostimulatory substances in concentrations that promote aquatic growth to the extent that such growths cause nuisance or adversely affect beneficial uses (RWQCB, 2007).
From the Basin Plan: For inland surface waters-streams and other flowing waters, with all beneficial uses, the water quality objective for total phosphorus is 0.1 mg/L (RWQCB, 2007). |
| Objective/Criterion Reference: |
Water Quality Control Plan for the San Diego Basin (9). |
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| Evaluation Guideline: |
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| Guideline Reference: |
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| Spatial Representation: |
Water samples were collected at Los Coches Creek station 2 (907SDLCO2). |
| Temporal Representation: |
Samples were collected in May 2004, September 2004; February 2005; and April 2005. |
| Environmental Conditions: |
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| QAPP Information: |
Quality control for the chemical analysis portion of this study was conducted in accordance with the California's Surface Water Ambient Monitoring Program. |
| QAPP Information Reference(s): |
2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA. |
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DECISION ID |
16566 |
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| Pollutant: |
Selenium |
| Final Listing Decision: |
List on 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: |
New Decision |
| Revision Status |
Revised |
| Sources: |
Source Unknown |
| Expected TMDL Completion Date: |
2019 |
| 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. Three of the 4 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. Three of the 4 samples exceed the CTR value for Se 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. |
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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 16566 |