Final California 2010 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 4 - Los Angeles Region

Water Body Name:	Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)
Water Body ID:	CAR4036200020000228094015
Water Body Type:	River & Stream


DECISION ID	6979	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	Chloride
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 (TMDL required list)(2006)
Revision Status	Revised
Sources:	Atmospheric Deposition \| Domestic Use of Ground Water \| Groundwater Loadings \| Irrigated Crop Production \| Major Municipal Point Source-dry weather discharge \| Surface Runoff
TMDL Name:	Calleguas Creek Chloride (3)
TMDL Project Code:	356
Date TMDL Approved by USEPA:	12/02/2008
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal on the section 303(d) list under sections 2.2 of the Listing Policy. Under 2.2 of the Policy, a minimum of one line of evidence is needed to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list. There is sufficient justification to place it in the Being Addressed portion of the 303(d) list because a TMDL has been completed and adopted by the Los Angeles RWQCB and approved by USEPA, and is expected to result in attainment of the standard.

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 Water Quality Limited Segments Being Addressed category of the section 303(d) list because a TMDL has been approved by USEPA, and 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:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 6979, Chloride	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

28008

Pollutant:

Chloride

LOE Subgroup:

Narrative Description Data

Matrix:

Not Specified

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

A TMDL has been approved for this water segment-pollutant combination. The Calleguas Creek Watershed Salts TMDL was adopted by the Los Angeles RWQCB on October 04, 2007 and subsequently approved by USEPA. The TMDL was integrated into the Basin Plan as Attachment A of Regional Board Resolution No. 2007-016.

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

QA information unavailable.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 6979, Chloride	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

4053

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Non-Contact Recreation

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 pre-2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

Unspecified

Guideline Reference:

Placeholder reference pre-2006 303(d)

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):


DECISION ID	6980	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	Sulfates
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 (TMDL required list)(2006)
Revision Status	Revised
Sources:	Atmospheric Deposition \| Domestic Use of Ground Water \| Groundwater Loadings \| Irrigated Crop Production \| Major Municipal Point Source-dry weather discharge \| Surface Runoff
TMDL Name:	Calleguas Creek Boron/Sulfate/TDS (4)
TMDL Project Code:	357
Date TMDL Approved by USEPA:	12/02/2008
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal on the section 303(d) list under sections 2.2 of the Listing Policy. Under 2.2 of the Policy, a minimum of one line of evidence is needed to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list. There is sufficient justification to place it in the Being Addressed portion of the 303(d) list because a TMDL has been completed and adopted by the Los Angeles RWQCB and approved by USEPA, and is expected to result in attainment of the standard.

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 Water Quality Limited Segments Being Addressed category of the section 303(d) list because a TMDL has been approved by USEPA, and 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:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 6980, Sulfates	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

28014

Pollutant:

Sulfates

LOE Subgroup:

Narrative Description Data

Matrix:

Not Specified

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

A TMDL has been approved for this water segment-pollutant combination. The Calleguas Creek Watershed Salts TMDL was adopted by the Los Angeles RWQCB on October 04, 2007 and subsequently approved by USEPA. The TMDL was been integrated into the Basin Plan as Attachment A of Regional Board Resolution No. 2007-016.

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

QA information unavailable.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 6980, Sulfates	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

4054

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Municipal & Domestic Supply

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 pre-2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

Unspecified

Guideline Reference:

Placeholder reference pre-2006 303(d)

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):


DECISION ID	6981	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	Total Dissolved Solids
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 (TMDL required list)(2006)
Revision Status	Revised
Sources:	Atmospheric Deposition \| Domestic Use of Ground Water \| Groundwater Loadings \| Irrigated Crop Production \| Major Municipal Point Source-dry weather discharge \| Surface Runoff
TMDL Name:	Calleguas Creek Boron/Sulfate/TDS (4)
TMDL Project Code:	357
Date TMDL Approved by USEPA:	12/02/2008
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal on the section 303(d) list under sections 2.2 of the Listing Policy. Under 2.2 of the Policy, a minimum of one line of evidence is needed to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list. There is sufficient justification to place it in the Being Addressed portion of the 303(d) list because a TMDL has been completed and adopted by the Los Angeles RWQCB and approved by USEPA, and is expected to result in attainment of the standard.

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 Water Quality Limited Segments Being Addressed category of the section 303(d) list because a TMDL has been approved by USEPA, and 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:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 6981, Total Dissolved Solids	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

4055

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Agricultural Supply

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 pre-2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

Unspecified

Guideline Reference:

Placeholder reference pre-2006 303(d)

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 6981, Total Dissolved Solids	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

28016

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Narrative Description Data

Matrix:

Not Specified

Fraction:

None

Beneficial Use:

Agricultural Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Data Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

QA information unavailable.

QAPP Information Reference(s):


DECISION ID	4508	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	Fecal Coliform
Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)(2006)
Revision Status	Original
Sources:	Nonpoint Source \| Point Source
Expected TMDL Completion Date:	2006
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the section 303(d) list under section 4.3 of the Listing Policy. Under section 4.3 a single line of evidence is necessary to assess delisting status. One line of evidence is available in the administrative record to assess this pollutant. Four samples exceed the Fecal Coliform water quality objective. Based on the readily available data and information, the weight of evidence indicates there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 2. Four of 12 samples exceeded the fecal coliform water quality objective but there is insufficient samples taken to determine whether the water body segment can be removed from the 303(d) list in accordance with the allowable frequency listed in Table 4.2 of the Listing Policy. 3. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

Regional Board Decision Recommendation:	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.

USEPA Action (if applicable):	USEPA approved the listing of this water body as a water quality limited segment requiring a TMDL for this pollutant.

Line of Evidence (LOE) for Decision ID 4508, Fecal Coliform	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

2158

Pollutant:

Fecal Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Twelve bacteria samples, 4 samples exceeding. Geomean of 557 exceeds 200/100 ml standard (SWRCB, 2003).

Data Reference:

Placeholder reference 2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Basin Plan: In waters designated for water contact recreation (REC-1), the fecal coliform concentration shall not exceed a log mean of 200/100 ml (based on a minimum of not less than four samples for any 30-day period), nor shall more than 10 percent of total samples during any 30-day period exceed 400/100 ml.

Objective/Criterion Reference:

Placeholder reference 2006 303(d)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One site.

Temporal Representation:

Summer, fall, winter, spring.

Environmental Conditions:

QAPP Information:

Calleguas Creek Characterization Study

QAPP Information Reference(s):


DECISION ID	6670	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	Sedimentation/Siltation
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2006)
Revision Status	Original
Sources:	Agriculture \| Natural Sources
Expected TMDL Completion Date:	2005
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for listing under section 2.2 of the Listing Policy. Under this section of the Policy, a minimum of one line of evidence is needed to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. A TMDL has been developed and is expected to result in attainment of the standard. The Calleguas Creek Historic Pesticides TMDL was approved by the RWQCB in 2005. Based on the readily available information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination in the Water Quality Limited Segments Being Addressed portion of the section 303(d) list. USEPA in its final decision for the 2006 303(d) list, has determined that a TMDL has not been approved by USEPA for this pollutant water body combination. Therefore, this water body pollutant combination is being placed back on the 303(d) list (TMDL required list) pending completion and USEPA approval of a TMDL.

Regional Board Decision Recommendation:	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.

USEPA Action (if applicable):	USEPA approved the listing of this water body as a water quality limited segment requiring a TMDL for this pollutant.

Line of Evidence (LOE) for Decision ID 6670, Sedimentation/Siltation	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

2160

Pollutant:

Sedimentation/Siltation

LOE Subgroup:

Pollutant-Water

Matrix:

Not Specified

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):


DECISION ID	4382	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	Ammonia
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)(2006)
Revision Status	Original
Sources:	Nonpoint Source \| Point Source
TMDL Name:	Calleguas Creek Nitrogen (1)
TMDL Project Code:	228
Date TMDL Approved by USEPA:	06/20/2003
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for listing under section 2.2 of the Listing Policy. Under this section of the Policy, a minimum of one line of evidence is needed to assess listing status. The Calleguas Creek Nitrogen TMDL was approved by RWQCB in October 2002 and was subsequently approved by USEPA in June 20, 2003. 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 in the Water Quality Limited Segments Being Addressed portion of the section 303(d) list.

Regional Board Decision Recommendation:	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.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 4382, Ammonia	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

2154

Pollutant:

Ammonia

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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):


DECISION ID	4576	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	Chlordane
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)(2006)
Revision Status	Original
Sources:	Source Unknown
TMDL Name:	Calleguas Creek Historic Pesticides (5)
TMDL Project Code:	358
Date TMDL Approved by USEPA:	03/14/2006
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Chlordane has not been specifically listed on the 303(d) list for this water body. The USEPA final decision for the 2006 303(d) list added this listing to the 'being addressed by USEPA approved TMDL portion of the 303(d) List because the Calleguas Creek OC Pesticides & PCBs TMDL was approved by USEPA on 03/14/2006.

Regional Board Decision Recommendation:	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.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 4576, Chlordane	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

2161

Pollutant:

Chlordane

LOE Subgroup:

Pollutant-Water

Matrix:

Not Specified

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 listing decision made by USEPA for 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):


DECISION ID	6355	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	Chlorpyrifos
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)(2006)
Revision Status	Original
Sources:	Source Unknown
TMDL Name:	Calleguas Creek Toxicity (2)
TMDL Project Code:	355
Date TMDL Approved by USEPA:	03/14/2006
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Chlorpyrifos has not been specifically listed on the 303(d) list for this water body. The USEPA final decision for the 2006 303(d) list added this listing to the 'being addressed by USEPA approved TMDL portion of the 303(d) List because the Calleguas Creek Toxicity TMDL was approved by USEPA on 03/14/2006.

Regional Board Decision Recommendation:	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.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 6355, Chlorpyrifos	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

2163

Pollutant:

Chlorpyrifos

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 listing decision made by USEPA for 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):


DECISION ID	6922	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	DDT (sediment)
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)(2006)
Revision Status	Original
Sources:	Nonpoint Source
TMDL Name:	Calleguas Creek Historic Pesticides (5)
TMDL Project Code:	358
Date TMDL Approved by USEPA:	03/14/2006
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for listing under section 2.2 of the Listing Policy. Under this section of the Policy, a minimum of one line of evidence is needed to assess listing status. The Calleguas Creek Historic Pesticides TMDL was approved by the RWQCB in 2005 and subsequently approved by USEPA on March 14, 2006 Based on the readily available information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination in the Water Quality Limited Segments Being Addressed portion of the section 303(d) list.

Regional Board Decision Recommendation:	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.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 6922, DDT (sediment)	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

2159

Pollutant:

DDT (sediment)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Not Recorded

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):


DECISION ID	6332	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

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)(2006)
Revision Status	Original
Sources:	Source Unknown
TMDL Name:	Calleguas Creek Toxicity (2)
TMDL Project Code:	355
Date TMDL Approved by USEPA:	03/14/2006
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Diazinon has not been specifically listed on the 303(d) list for this water body. The USEPA final decision for the 2006 303(d) list added this listing to the 'being addressed by USEPA approved TMDL portion of the 303(d) List because the Calleguas Creek Toxicity TMDL was approved by USEPA on 03/14/2006.

Regional Board Decision Recommendation:	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.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 6332, Diazinon	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

2164

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Not Specified

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 listing decision made by USEPA for 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):


DECISION ID	6089	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	Dieldrin
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)(2006)
Revision Status	Original
Sources:	Source Unknown
TMDL Name:	Calleguas Creek Historic Pesticides (5)
TMDL Project Code:	358
Date TMDL Approved by USEPA:	03/14/2006
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Dieldrin has not been specifically listed on the 303(d) list for this water body. The USEPA final decision for the 2006 303(d) list added this listing to the 'being addressed by USEPA approved TMDL portion of the 303(d) List because the Calleguas Creek OC Pesticides & PCBs TMDL was approved by USEPA on 03/14/2006.

Regional Board Decision Recommendation:	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.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 6089, Dieldrin	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

2162

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Water

Matrix:

Not Specified

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 listing decision made by USEPA for 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):


DECISION ID	4365	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	Nitrate and Nitrite
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)(2006)
Revision Status	Original
Sources:	Nonpoint Source \| Point Source
TMDL Name:	Calleguas Creek Nitrogen (1)
TMDL Project Code:	228
Date TMDL Approved by USEPA:	06/20/2003
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for listing under section 2.2 of the Listing Policy. Under this section of the Policy, a minimum of one line of evidence is needed to assess listing status. The Calleguas Creek Nitrogen TMDL was adopted by the RWQCB in October 2002 and subsequently approved by USEPA on June 20, 2003. 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 in the Water Quality Limited Segments Being Addressed portion of the section 303(d) list.

Regional Board Decision Recommendation:	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.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 4365, Nitrate and Nitrite	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

2155

Pollutant:

Nitrate and Nitrite

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Municipal & Domestic Supply

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):


DECISION ID	4364	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	Nitrate as Nitrate (NO3)
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)(2006)
Revision Status	Original
Sources:	Nonpoint Source \| Point Source
TMDL Name:	Calleguas Creek Nitrogen (1)
TMDL Project Code:	228
Date TMDL Approved by USEPA:	06/20/2003
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for delisting under sections 4.1 of the Listing Policy. Under section 4.1 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. The Calleguas Creek Nitrogen TMDL was adopted by RWQCB in October 2002 and was subsequently approved by USEPA in June 20, 2003. Based on the readily available information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination in the Water Quality Limited Segments Being Addressed portion of the section 303(d) list. 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. Eight out of 12 samples the water quality objective. However, a TMDL is in place to address this pollutant in this water body. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	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.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 4364, Nitrate as Nitrate (NO3)	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

2157

Pollutant:

Nitrate as Nitrate (NO3)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Groundwater Recharge

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Twelve water samples, 8 samples exceeding (SWRCB,2003).

Data Reference:

Placeholder reference 2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Basin Plan: Waters shall not exceed 10 mg/L nitrogen as nitrate-nitrogen plus nitrite-nitrogen (NO2-N), 45 mg/L as nitrate (NO3), 10 mg/L as nitrate-nitrogen (NO3-N) or as otherwise designated in another part of the Basin Plan.

Objective/Criterion Reference:

Placeholder reference 2006 303(d)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One site.

Temporal Representation:

Summer, fall, winter, spring.

Environmental Conditions:

QAPP Information:

NPDES reports.

QAPP Information Reference(s):


DECISION ID	6091	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

Pollutant:	Toxicity
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)(2006)
Revision Status	Original
Sources:	Source Unknown
TMDL Name:	Calleguas Creek Toxicity (2)
TMDL Project Code:	355
Date TMDL Approved by USEPA:	03/14/2006
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Toxicity has not been specifically listed on the 303(d) list for this water body. The USEPA final decision for the 2006 303(d) list added this listing to the 'being addressed by USEPA approved TMDL portion of the 303(d) List because the Calleguas Creek Toxicity TMDL was approved by USEPA on 03/14/2006.

Regional Board Decision Recommendation:	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.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 6091, Toxicity	Region 4
Calleguas Creek Reach 6 ( was Arroyo Las Posas Reaches 1 and 2 on 1998 303d list)

LOE ID:

2165

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

Not Recorded

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 listing decision made by USEPA for 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):