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

Supporting Information

Regional Board 2 - San Francisco Bay Region

Water Body Name:	Suisun Slough
Water Body ID:	CAE2072300020020315202246
Water Body Type:	Estuary


DECISION ID	100850	Region 2
Suisun Slough

Pollutant:	Mercury
Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	Historic Land Management Activities
TMDL Name:	Suisun Marsh Dissolved Oxygen and Mercury TMDL
TMDL Project Code:	553
Date TMDL Approved by USEPA:	12/31/2018
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Suisun Slough is part of the Suisun Marsh system. As such, the impairments for Suisun Marsh are applicable to sloughs within the marsh. Further, the TMDL for Suisun Marsh will resolve the impairments for sloughs within the Suisun Marsh system. Accordingly, the mercury impairment in Suisun Slough will be addressed and resolved by the Suisun Marsh TMDL for dissolved oxygen approved by USEPA on 12/31/2018.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 100850, Mercury	Region 2
Suisun Slough

LOE ID:

125246

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

This is a placeholder LOE to allow Suisun Slough mercury impairment to be associated with the TMDL for Suisun Marsh

Data Reference:

Staff Report for Proposed Basin Plan Amendment - Establish Water Quality Objectives and a Total Maximum Daily Load for Dissolved Oxygen in Suisun Marsh and add Suisun Marsh to the SF Bay Mercury TMDL

SWAMP Data:

Water Quality Objective/Criterion:

This is a placeholder LOE to allow Suisun Slough mercury impairment to be associated with the TMDL for Suisun Marsh. This placeholder LOE will fulfill database requirements to create a listing for Suisun Slough. This slough listing will subsequently be associated with the TMDL for Suisun Marsh - which aims to resolve the mercury and low DO/organic enrichment impairments. Suisun Slough is part of the Suisun Marsh system so resolution of the Suisun Marsh impairments will resolve those in Suisun Slough as well.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

This is a placeholder LOE to allow Suisun Slough mercury impairment to be associated with the TMDL for Suisun Marsh.

QAPP Information Reference(s):


DECISION ID	100851	Region 2
Suisun Slough

Pollutant:	Oxygen, Dissolved
Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	Historic Land Management Activities
TMDL Name:	Suisun Marsh Dissolved Oxygen and Mercury TMDL
TMDL Project Code:	553
Date TMDL Approved by USEPA:	12/31/2018
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Suisun Slough is part of the Suisun Marsh system. As such, the impairments for Suisun Marsh are applicable to sloughs within the marsh. Further, the TMDL for Suisun Marsh will resolve the impairments for sloughs within the Suisun Marsh system. Accordingly, the dissolved oxygen impairment in Suisun Slough will be addressed and resolved by the Suisun Marsh TMDL for dissolved oxygen approved by USEPA on 12/31/2018. We should note that the impairment for Suisun Marsh was originally for organic enrichment/low dissolved oxygen. While this original pollutant description is the most accurate, the impairment for this slough is given as low dissolved oxygen.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 100851, Oxygen, Dissolved	Region 2
Suisun Slough

LOE ID:

125375

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

This is a placeholder LOE to allow Suisun Slough dissolved oxygen impairment to be associated with the TMDL for Suisun Marsh

Data Reference:

Staff Report for Proposed Basin Plan Amendment - Establish Water Quality Objectives and a Total Maximum Daily Load for Dissolved Oxygen in Suisun Marsh and add Suisun Marsh to the SF Bay Mercury TMDL

SWAMP Data:

Water Quality Objective/Criterion:

This is a placeholder LOE to allow Suisun Slough dissolved oxygen impairment to be associated with the TMDL for Suisun Marsh. This placeholder LOE will fulfill database requirements to create a listing for Suisun Slough. This slough listing will subsequently be associated with the TMDL for Suisun Marsh - which aims to resolve the mercury and low DO/organic enrichment impairments. Suisun Slough is part of the Suisun Marsh system so resolution of the Suisun Marsh impairments will resolve those in Suisun Slough as well.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

This is a placeholder LOE to allow Suisun Slough dissolved oxygen impairment to be associated with the TMDL for Suisun Marsh

QAPP Information Reference(s):


DECISION ID	69483	Region 2
Suisun Slough

Pollutant:	Diazinon
Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)(2016)
Revision Status	Original
Sources:	A Source Unknown
TMDL Name:	San Francisco Bay Urban Creeks Diazinon
TMDL Project Code:	9
Date TMDL Approved by USEPA:	05/16/2007
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	303(d) listing decisions made prior to 2006 were not held in an assessment database. The Regional Boards will update this decision when new data and information become available and are assessed. The USEPA final decision on the 2006 303(d) list was to move this listing to the being addressed by a USEPA approved TMDL portion of the 303(d) list, because the San Francisco Bay Urban Creeks Diazinon TMDL was approved by USEPA on 5/16/07 (USEPA, 2007).

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 69483, Diazinon	Region 2
Suisun Slough

LOE ID:

473

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.

Data Reference:

Placeholder reference 2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

QA Info Missing

QAPP Information Reference(s):