Final California 2020 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 2 - San Francisco Bay Region

Water Body Name:	Webb Creek
Water Body ID:	CAR2013001220080626103512
Water Body Type:	River & Stream


DECISION ID	70669	Region 2
Webb Creek

Pollutant:	Benthic-Macroinvertebrate Bioassessments \| Oxygen, Dissolved \| Temperature, water
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This water body 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. Three lines of evidence are available in the administrative record to assess this water body. Based on the readily available data for this water body, 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. Temperature and dissolved oxygen measurements at all 3 continuous deployments did not exceed the applicable water quality objectives for waters designated as cold water habitat and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. In addition, the macroinvertebrate data indicated excellent water quality conditions. 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:	This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current. The decision has not changed.

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.

Line of Evidence (LOE) for Decision ID 70669, Multiple Pollutants	Region 2
Webb Creek

LOE ID:

5716

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water quality assessment was conducted at Webb Creek as part of SWAMP study in 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 one location.

The 7 day average minimum concentration of dissolved oxygen was 10.72 mg/L during dry season, 11.66 mg/L during spring season, and 11.4 mg/L during winter wet season. All DO measurements met the water quality objective of 7 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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The numeric water quality objective for dissolved oxygen is 7.0 mg/L minimum for waters designated as cold 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:

Water Quality Control Plan (Basin Plan) - San Francisco Bay Region (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Dissolved oxygen concentrations were measured at one site located just upstream from Hwy 1.

Temporal Representation:

DO was recorded at 15 minute intervals over 6 to 7 days during spring (April 2005), summer dry season (August 2005), and winter wet season (January 2006).

Environmental Conditions:

QAPP Information:

All samples were collected and analyzed using procedures comparable with the SWAMP Quality Assurance Management Plan (SWRCB 2002).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 70669, Multiple Pollutants	Region 2
Webb Creek

LOE ID:

5856

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Benthic macroinvertebrates were sampled from one site in the Webb Creek watershed in April 2005 by the SWAMP program. Benthic macroinvertebrate assemblage metrics were no different to values observed at reference sites in perennial creeks and indicated excellent conditions. Taxa richness score was 39 and % sensitive EPT was 26.

Data Reference:

Data collected by the Surface Water Ambient Monitoring Program, San Francisco Bay Regional Water Quality Control Board. Years 4 and 5 Assessment

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are lethal to or that produce significant alterations in population or community ecology or receiving water biota. In addition, the health and life history characteristics of aquatic organisms in waters affected by controllable water quality factors shall not differ significantly from those for the same waters in areas unaffected by controllable water quality factors.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - San Francisco Bay Region (Region 2)

Evaluation Guideline:

Benthic macroinvertebrate assemblage metric scores that are within the range of scores for minimally disturbed reference sites indicate no substantial alterations in community ecology. Taxa richness values at reference sites sampled by the SWAMP program between 2001 and 2003 ranged from 28 to 59. Reference conditions determined for perennial streams such as Webb Creek, usually exhibit taxa richness > 38 and % sensitive EPT > 44. A perennial stream could be described as in - excellent condition - if there is no difference between the metrics measured at the site and those established for reference sites. A perennial stream will be described as in - good condition - if the site metrics indicate minor loss of bio-integrity but still a good structure and function, and sensitive species are present in abundance.

Guideline Reference:

Water Quality Monitoring and Bioassessment in Nine San Francisco Bay Region Watersheds: Walker Creek, Lagunitas Creek, San Leandro Creek, Wildcat Creek/San Pablo Creek, Suisun Creek, Arroyo Las Positas, Pescadero Creek/Butano Creek, San Gregorio Creek, and Stevens Creek/Permanente Creek. Oakland, CA: Surface Water Ambient Monitoring Program, San Francisco Bay Regional Water Quality Control Board

Spatial Representation:

Benthic macroinvertebrates were sampled from one site located upstream from Hwy 1.

Temporal Representation:

Benthic macroinvertebrates were sampled once in April, 2005.

Environmental Conditions:

QAPP Information:

All samples were collected and analyzed using procedures comparable with the SWAMP Quality Assurance Management Plan (SWRCB 2002).

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 70669, Multiple Pollutants	Region 2
Webb Creek

LOE ID:

5715

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water quality assessment was conducted at Webb Creek as part of SWAMP study in 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 one location.

The estimated 7-day mean temperature was 11.79°C in spring, 13.69°C during dry summer season, and 10.51 °C during wet season. The 14.8 °C criterion for coho salmon and the 17 °C criterion for steelhead were never exceeded.

Data Reference:

Data collected by the Surface Water Ambient Monitoring Program, San Francisco Bay Regional Water Quality Control Board. Years 4 and 5 Assessment

SWAMP Data:

SWAMP

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 Water Board that such alteration in temperature 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:

Water Quality Control Plan (Basin Plan) - San Francisco Bay Region (Region 2)

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 the 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 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

Spatial Representation:

Temperature was measured at one site located just upstream from Hwy 1.

Temporal Representation:

Temperature was recorded at 15 minute intervals over 6 to 7 days during spring (April 2005), summer dry season (August 2005), and winter wet season (January 2006).

Environmental Conditions:

QAPP Information:

All samples were collected and analyzed using procedures comparable with the SWAMP Quality Assurance Management Plan (SWRCB 2002).

QAPP Information Reference(s):


DECISION ID	76761	Region 2
Webb Creek

Pollutant:	pH
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
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. 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. None of the three samples exceeded the water quality objective (Basin Plan) and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. A minimum of five samples is needed. 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:	This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current. The decision has not changed.

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.

Line of Evidence (LOE) for Decision ID 76761, pH	Region 2
Webb Creek

LOE ID:

28226

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

In 2005 the SWAMP Program performed continuous monitoring of pH at 15-minute intervals at one monitoring site in Webb Creek. All pH measurements were within the recommended range.

Data Reference:

Data collected by the Surface Water Ambient Monitoring Program, San Francisco Bay Regional Water Quality Control Board. Years 4 and 5 Assessment

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The pH shall not be depressed below 6.5 nor raised above 8.5. This encompasses the pH range usually found in waters within the basin. Controllable water quality factors shall not cause changes greater than 0.5 units in normal ambient pH levels.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - San Francisco Bay Region (Region 2)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Measurements were taken at the WBB010 monitoring location.

Temporal Representation:

pH was recorded during spring, dry, and wet season of 2005-2006 monitoring period.

Environmental Conditions:

QAPP Information:

The QA/QC procedure was comparable with SWAMP'S Quality Assurance Management Plan of 2002.

QAPP Information Reference(s):