| Data Used to Assess Water Quality: |
Water quality assessment was conducted at Islais Creek watershed as part of SWAMP assessment in 2005 and 2006. Continuous field monitoring of temperature, dissolved oxygen, pH, and specific conductance to determine temporal variability in basic water quality at one location. The 7 day average dissolved oxygen level ranged from 7.9 to 9.9 mg/L and varied with season. The 7 day average DO did not drop below the minimum at any deployment during the sampling season. |
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DECISION ID |
17579 |
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| Pollutant: |
Temperature, water |
| 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 this section 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. None 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. Zero of two samples exceeded the water quality objective, but 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 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 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: |
29262 |
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| Pollutant: |
Temperature, water |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Cold Freshwater Habitat |
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| Number of Samples: |
2 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
PHYSICAL/CHEMICAL MONITORING |
| Data Used to Assess Water Quality: |
Water quality assessment was conducted at Islais Creek watershed as part of SWAMP assessment in 2005 and 2006. Continuous field monitoring of temperature, dissolved oxygen, pH, and specific conductance to determine temporal variability in basic water quality at one location. The temperature did not exceed the 17.0°C at either deployment during the sampling season. |
| 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: |
Temperature objectives for enclosed bays and estuaries are specified in the "Water Quality Control Plan for Control of Temperature in the Coastal and Interstate Waters and Enclosed Bays of California" including any revisions to the plan. In addition, the following temperature objectives apply to surface waters: The natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such an alteration does not adversely affect beneficial uses. The temperature of any cold or warm freshwater habitat shall not be increased by more than 5°F (2.8°C) above natural receiving water temperature. |
| Objective/Criterion Reference: |
San Francisco Bay Basin (Region 2) Water Quality Control Plan (Basin Plan) |
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| Evaluation Guideline: |
Sullivan et al. (2000) reviewed a wide range of studies incorporating information from laboratory-based research, field observations, and risk assessment approaches and developed criteria for assessing temperature risk to aquatic life. The 7-day mean temperature (maximum value of a 7-day moving average of the daily mean temperature) of 14.8°C was established as the upper threshold criterion for coho salmon and 17.0°C for steelhead trout. The risk assessment approach used by Sullivan et al. (2000) suggests that temperatures exceeding the above thresholds will cause a 10% reduction in average growth compared to optimal conditions. |
| Guideline Reference: |
An Analysis of the Effects of Temperature on Salmonids of the Pacific Northwest with Implications for Selecting Temperature Criteria |
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| Spatial Representation: |
Temperature was measured at one site ISL050 (Glen Canyon Park) located on the mainstem of Islais Creek representative of the entire creek length. |
| Temporal Representation: |
The SWAMP performed continuous monitoring of dissolved oxygen at 15 minute intervals lasting 8-12 days during spring (May 2005), and winter wet season (January 2006). |
| 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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DECISION ID |
17580 |
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| Pollutant: |
pH |
| 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 this section 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. None 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. Zero of two samples exceeded the water quality objective, but 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 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 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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Lines of Evidence (LOEs) for Decision ID 17580 |