| Water Body Name: | Oso Creek (lower) |
| Water Body ID: | CAR9012000020010831154628 |
| Water Body Type: | River & Stream |
DECISION ID |
16619 |
Region 9 |
Oso Creek (lower) |
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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 |
| Regional Board Conclusion: | 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. Three of the four samples exceed the Basin Plan water quality objective for total nitrogen as N. 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. Three of the four samples exceed the Basin Plan water quality objective for total nitrogen as N and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of five samples is needed for application of table 3.2. 4. Pursuant to [SECTION 3.11/4.11] of the Listing Policy, no additional data and information are available indicating that standards are not met. |
| Regional Board Decision 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. |
| 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. |
| USEPA Action (if applicable): | |
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| LOE ID: | 9095 | ||||
| Pollutant: | Total Nitrogen as N | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Not Recorded | ||||
| Beneficial Use: | Warm Freshwater Habitat | ||||
| Number of Samples: | 4 | ||||
| Number of Exceedances: | 3 | ||||
| Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants) | ||||
| Data Used to Assess Water Quality: | Four water samples were collected at Oso Creek 3 Station 901SJOSO3 on October 2002, January 2003, April 2003, and May 2003, four of the four samples showed excessive nitrogen concentrations (SWAMP, 2007). | ||||
| Data Reference: | Monitoring data for Region 9 | ||||
| SWAMP Data: | SWAMP | ||||
| 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). |
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| Objective/Criterion Reference: | Water Quality Control Plan for the San Diego Basin | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | Water samples were collected at Oso Creek 3 Station (901SJOSO3). (Latitude 33.5348, Longitude -117.6762). | ||||
| Temporal Representation: | Samples were collected on October 2002, January 2003, April 2003, and May 2003. | ||||
| Environmental Conditions: | |||||
| 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 | ||||
DECISION ID |
16616 |
Region 9 |
Oso Creek (lower) |
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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 |
| Regional Board Conclusion: | 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. Three of the four samples exceed the Basin Plan water quality objective for phosphorus. 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. Three of the four samples exceed the Basin Plan water quality objective for phosphorus and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of five samples is needed for application of table 3.2. 4. Pursuant to [SECTION 3.11/4.11] of the Listing Policy, no additional data and information are available indicating that standards are not met. |
| Regional Board Decision 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. |
| 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. |
| USEPA Action (if applicable): | |
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| LOE ID: | 9093 | ||||
| Pollutant: | Phosphorus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Not Recorded | ||||
| Beneficial Use: | Warm Freshwater Habitat | ||||
| Number of Samples: | 4 | ||||
| Number of Exceedances: | 3 | ||||
| Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants) | ||||
| Data Used to Assess Water Quality: | Four water samples were collected at Oso Creek Station 901SJOSO3 on October 2002, January 2003, April 2003, and May 2003, three of the four samples showed excessive phosphorus concentrations (SWAMP, 2007). | ||||
| Data Reference: | Monitoring data for Region 9 | ||||
| SWAMP Data: | SWAMP | ||||
| 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.
Water Quality Control Plan for the San Diego Basin Goal of 0.1 mg/L for total phosphorus in streams and other flowing waters (RWQCB, 2007). |
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| Objective/Criterion Reference: | Water Quality Control Plan for the San Diego Basin | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | Water samples were collected at Oso Creek 3 Station (901SJOSO3). (Latitude 33.5348, Longitude -117.6762). | ||||
| Temporal Representation: | Samples were collected on October 2002, January 2003, April 2003, and May 2003. | ||||
| Environmental Conditions: | |||||
| 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 | ||||
DECISION ID |
16617 |
Region 9 |
Oso Creek (lower) |
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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: | 2021 |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | Regional Board Conclusion:
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. Three of the four samples exceed the Basin Plan water quality objective for selenium. 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. Three of the four samples exceed the Basin Plan water quality objective for selenium and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of five samples is needed for application of table 3.2. 4. Pursuant to [SECTION 3.11/4.11] of the Listing Policy, no additional data and information are available indicating that standards are not met. State Board Review and Conclusion: The Regional Board staff incorrectly assessed selenium as a conventional pollutant and applied table 3.2 of the listing Policy. Selenium is a toxicant and should be assessed using Table 3.1 . State Water Board staff has corrected this error and revised the recommendation to List for selenium. The revised recommendation is as follows: 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. Four of the four samples exceed the water quality objective for selenium. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for 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 four samples exceeded the water quality objective for selenium and this exceeds the allowable frequency under Section 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. |
| Regional Board Decision 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. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | After review of this Regional Board decision, SWRCB staff recommend the following changes to the decision:
The water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards for the pollutant are being exceeded. |
| USEPA Action (if applicable): | USEPA approved the listing of this water body as a water quality limited segment requiring a TMDL for this pollutant. |
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| LOE ID: | 9094 | ||||
| Pollutant: | Selenium | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Dissolved | ||||
| Beneficial Use: | Warm Freshwater Habitat | ||||
| Number of Samples: | 4 | ||||
| Number of Exceedances: | 3 | ||||
| Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants) | ||||
| Data Used to Assess Water Quality: | Four water samples were collected at Oso Creek Station 901SJOSO3 on October 2002, January 2003, April 2003, and May 2003, three of the four samples showed excessive phosphorus concentrations. | ||||
| Data Reference: | Monitoring data for Region 9 | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | CTR Freshwater Chronic (CCC) 5 ug/L. | ||||
| Objective/Criterion Reference: | Water Quality Control Plan for the San Diego Basin | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | Water samples were collected at Oso Creek 3 Station (901SJOSO3). (Latitude 33.5348, Longitude -117.6762). | ||||
| Temporal Representation: | Samples were collected on October 2002, January 2003, April 2003, and May 2003. | ||||
| Environmental Conditions: | |||||
| 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 | ||||
DECISION ID |
16620 |
Region 9 |
Oso Creek (lower) |
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| Pollutant: | Toxicity |
| Final Listing Decision: | List on 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: | New Decision |
| Revision Status | Revised |
| Sources: | Unknown Nonpoint Source | Urban Runoff/Storm Sewers |
| Expected TMDL Completion Date: | 2021 |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | This pollutant is being considered for placement on the section 303(d) list under section 3.6 of the Listing Policy. Under section 3.6 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 four samples exceed the Basin Plan water quality objective for toxicity. 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. Four of the four samples exceed the Basin Plan water quality objective for toxicity 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. |
| Regional Board Decision Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body should be placed on the section 303(d) list for toxicity because applicable water quality standards for toxicity are exceeded. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | Selenium is a toxicant and should be assessed using Table 3.1 instead of 3.2. This will result in a listing decision |
| USEPA Action (if applicable): | USEPA approved the listing of this water body as a water quality limited segment requiring a TMDL for this pollutant. |
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| LOE ID: | 21400 | ||||
| Pollutant: | Toxicity | ||||
| LOE Subgroup: | Toxicity | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Warm Freshwater Habitat | ||||
| Number of Samples: | 4 | ||||
| Number of Exceedances: | 4 | ||||
| Data and Information Type: | Ambient toxicity testing (chronic) | ||||
| Data Used to Assess Water Quality: | Four samples were collected at Oso Creek station 901SJOSO3 from October 2002 to May 2003, they showed significant toxicity levels (SL) in the following tests: Selenastrum algae growth test: All four samples were toxic. Ceriodaphnia dubia survival/reproductive test : Two of the three samples were toxic. | ||||
| Data Reference: | Monitoring data for Region 9 | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | From the Basin Plan, all waters shall be free of toxic substances that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. | ||||
| Objective/Criterion Reference: | Water Quality Control Plan for the San Diego Basin | ||||
| Evaluation Guideline: | According to SWAMP, waters are considered toxic when samples show significant toxicity levels (SWAMP code SL) when compared to a negative control. Significant toxicity is determined when statistical tests result in an alpha of less than 5% and percent control values less than the evaluation threshold. | ||||
| Guideline Reference: | Monitoring data for Region 9 | ||||
| Spatial Representation: | Water toxicity samples were collected at Oso Creek station 3, 901SJOSO3; (Latitude 33.5348, Longitude -117.6762). | ||||
| Temporal Representation: | Samples were collected on October 2002, January 2003, April 2003, and May 2003. | ||||
| Environmental Conditions: | |||||
| 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 | ||||