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DECISION ID |
10872 |
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| Pollutant: |
Oxygen, Dissolved |
| 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 listing 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.
Based on the readily available data for this water body, the weight of evidence indicates that there is sufficient justification available 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 satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. Dissolved oxygen measurements at seven continuous deployments did not exceed the applicable water quality objectives for waters designated as warm water habitat 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, Water Board staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there is insufficient number of exceedances to determine that the standards are not met. |
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| SWRCB Board Decision / Staff Recommendation: |
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| USEPA Decision: |
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| LOE ID: |
23498 |
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| Pollutant: |
Low Dissolved Oxygen |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Warm Freshwater Habitat |
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| Number of Samples: |
7 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
PHYSICAL/CHEMICAL MONITORING |
| Data Used to Assess Water Quality: |
A water quality assessment was conducted in Lion Creek as part of SWAMP study in 2004- 2005. Continuous field monitoring at 15 minute increments of temperature, dissolved oxygen, pH and specific conductance was conducted to determine temporal variability in basic water quality at three locations.
The 7 day average minimum concentration of dissolved oxygen was 5.3 mg/L during summer dry season, 8.8 mg/L during spring season, and 10.7 mg/L during winter wet season. Dissolved oxygen measurements during 7 deployments met the water quality objective of 5 mg/L. |
| Data Reference: |
Data collected by the Surface Water Ambient Monitoring Program, San Francisco Bay Regional Water Quality Control Board. Years 4 and 5 Assessment |
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| Water Quality Objective/Criterion: |
The numeric water quality objective for dissolved oxygen is 5.0 mg/L minimum for waters designated as warm water habitat. The median dissolved oxygen concentration for any three consecutive months shall not be less than 80 percent of the dissolved oxygen content at saturation. |
| Objective/Criterion Reference: |
San Francisco Bay Basin (Region 2) Water Quality Control Plan (Basin Plan) |
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| Evaluation Guideline: |
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| Guideline Reference: |
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| Spatial Representation: |
Dissolved oxygen concentrations were measured at three monitoring sites. Two of these sites are located just below the western slopes of the East Bay ridge and one site is located at the lower reach of the creek which is adjacent to urban area just west of Hwy 185. |
| Temporal Representation: |
Dissolved oxygen was recorded at 15 minute intervals over 6 to 7 days during spring (May 2004), summer dry season (August 2004), and winter wet season (February 2005). |
| Environmental Conditions: |
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| QAPP Information: |
All samples were collected and analyzed using procedures comparable with the SWAMP Quality Assurance Management Plan (SWRCB 2002). |
| QAPP Information Reference(s): |
Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
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