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

Supporting Information

Regional Board 4 - Los Angeles Region

Water Body Name:	Las Virgenes Creek
Water Body ID:	CAR4042201019990201141611
Water Body Type:	River & Stream


DECISION ID	17207	Region 4
Las Virgenes Creek

Pollutant:	Benthic-Macroinvertebrate Bioassessments
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	Source Unknown
Expected TMDL Completion Date:	2021
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Regional Board Conclusion: This pollutant is being considered for the section 303(d) list under section 3.9 of the Listing Policy. Under section 3.9, waters are listed when a bioassessment shows diminished numbers of species or other metrics (compared to a reference site) and it is associated with a pollutant. Three lines of evidence are available in the administrative record to assess this pollutant. Benthic macroinvertebrates as measured by Southern California IBI (Index of Biological Integrity) in Las Virgenes Creek were poor and very poor at two sites in winter of 2005; very poor and poor at two sites in the spring and poor and very poor at two sites in the fall indicating impairment of benthic community structure. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification to place the water segment in category 4C on 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. There is at least one bioassessment sample (Index of Biological Integrity score) to satisfy Section 3.9 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met. State Board Review and Conclusion: State Water Board staff used a situation-specific weight of evidence approach to evaluate the Los Angeles Water Board benthic macroinvertebrate bioassessment listing. State Water Board staff determined that it is necessary to include these listings because additional data analyses and multiple line of evidence show that benthic macroinvertebrate populations are impacted by a wide range of stressors. Using this approach staff followed a three-step process for evaluation of all available water quality data including the chemistry and bioassessment data. In the first step, staff reviewed the Los Angeles Water Board data evaluation for bioassessment listing. In the second step, staff reviewed all other available bioassessment data because State Water Board staff learned that some data had not been considered for this listing decision by the Regional Water Board. In step 3 staff reviewed the chemistry water quality data available for dissolved oxygen and total nitrogen to determine the water quality condition in this water body segment. In step 1 and 2, State Water Board staff evaluated the bioassessment data using the Southern California index of biological integrity (IBI). Staff reviewed the line of evidence prepared by the Los Angeles Water Board and additional bioassessment data. Benthic macroinvertebrate as measured by Southern California IBI in Las Virgenes Creek were poor from 2005 through 2008 indicating impairment of benthic community structure. In step 3, the chemistry data for dissolved oxygen and total nitrogen were evaluated by State Water Board staff. Data for dissolved oxygen and total nitrogen were evaluated in a previous listing cycle. Dissolved oxygen and total nitrogen showed impairment to the warm freshwater habitat and it resulted in listing this water body in 1996 and 1998. In this step State Water Board staff evaluated the most recent available data for dissolved oxygen and total nitrogen. The data for dissolved oxygen show that 19 of 30 samples exceeded the water quality objective of 5.0 mg/L. The data for total nitrogen show that 64 of 66 samples exceeded the water quality objective of 1.0 mg/L. The weight of evidence of the data and information indicate that the beneficial use of the water is not supported. The water quality chemistry and bioassessment data provide a substantial basis that benthic macroinvertebrate populations are impacted by a wide range of anthropogenic stressors. Based on the available data and information, staff recommend to list for benthic macroinvertebrate-bioassessment.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be added to the section 303(d) list because applicable water quality standards are not being attained.

State Board Review of Regional Board Conclusion and Recommendation:	The water quality chemistry and bioassessment data provide a substantial basis that benthic macroinvertebrate populations are impacted by a wide range of anthropogenic stressors. Based on the available data and information, staff recommend to list for benthic macroinvertebrate-bioassessment.

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 17207, Benthic-Macroinvertebrate Bioassessments	Region 4
Las Virgenes Creek

LOE ID:

30175

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Fish Migration | Fish Spawning | Preservation of Rare & Endangered Species | Wetland Habitat | Wildlife Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

The IBI scores at these sites ranked in the very poor and poor range (12 and 25) in the spring and poor and very poor range (11 and 23) in the fall.

Data Reference:

Malibu Watershed 2005 Bioassessment Monitoring Report. (2005) The Malibu Creek Watershed Monitoring Program City of Calabasas, Environmental Services Division. Submitted by: Aquatic Bioassay and Consulting Laboratories.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan states that: "All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant or animal, or aquatic life. Compliance with this objective will be determined by use of indicator organisms, analysis of species diversity, population density, growth anomalies, bioassays of appropriate duration or other appropriate methods as specified by the State or Regional Board.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The IBI is a multi-metric assessment that employs biological metrics that respond to a habitat or water quality impairment. Each of the biological metrics measured at a site are converted to an IBI score then summed. These cumulative scores are then ranked as very good (80-100), good (60-79), fair (40-49), poor (20-39) and very poor (0-19) habitat conditions. Sites with scores below 39 are considered to have impaired conditions.

Guideline Reference:

A Quantitative Tool for Assessing the Integrity of Southern Coastal California Streams. Appendix 7-B Environmental Management Vol. 35, No. 4, pp. 493-504.

Spatial Representation:

Two sites in Las Virgenes Creek were sampled, LV1 at 34° 10.108' N 118° 42.155' W and LV2 at 34° 07.507' N 118° 42.494' W

Temporal Representation:

Sites were sampled in Spring and Fall of 2005

Environmental Conditions:

Benthic macroinvertebrate populations and IBI scores may also be affected by a wide range of anthropogenic stressors.

QAPP Information:

Data was collected in compliance with California Stream Bioassessment Procedure.

QAPP Information Reference(s):

California Stream Bioassessment Procedure (Protocol Brief for Biological and Physical/Habitat Assessment in Wadeable Streams) California Department of Fish and Game Water Pollution Control Laboratory Aquatic Bioassessment Laboratory Revision Date - December, 2003

Line of Evidence (LOE) for Decision ID 17207, Benthic-Macroinvertebrate Bioassessments	Region 4
Las Virgenes Creek

LOE ID:

30174

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Fish Migration | Fish Spawning | Preservation of Rare & Endangered Species | Wetland Habitat | Wildlife Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Two sites sampled in 2005 IBI scores were calculated at 17 category very poor and 34, category poor.

Data Reference:

Malibu Bioassessment Winter 2005

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

A Quantitative Tool for Assessing the Integrity of Southern Coastal California Streams. Appendix 7-B Environmental Management Vol. 35, No. 4, pp. 493-504.

Spatial Representation:

Two sites in Las Virgenes Creek were sampled, LV5 and LV9.

Temporal Representation:

Sites were sampled in winter of 2005.

Environmental Conditions:

Benthic macroinvertebrate populations and IBI scores may also be affected by a wide range of anthropogenic stressors.

QAPP Information:

Data was collected in compliance with California Stream Bioassessment Procedure. Collection procedures were audited by California Department of Fish and Game in 2006.

QAPP Information Reference(s):

California Stream Bioassessment Procedure Biological and Physical Habitat Field Audit

Line of Evidence (LOE) for Decision ID 17207, Benthic-Macroinvertebrate Bioassessments	Region 4
Las Virgenes Creek

LOE ID:

28703

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Fish Migration | Fish Spawning | Preservation of Rare & Endangered Species | Wetland Habitat | Wildlife Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

A total of three of five sites showed an increase in density of mud snails over the three years of sampling (2006, 2007, 2008) and six of 10 sites sampled showed medium or high densities of mud snail in 2008.

Data Reference:

New Zealand Mudsnail Surveys July 2006, July 2007 and October 2008 Santa Monica Mountains. Santa Monica Bay Restoration Commission / Santa Monica Baykeeper.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Presence of high densities and increasing densities. While quantitative and predictive research continues, due to its ability to attain extremely high densities, the impacts of the mudsnails on aquatic ecosystems where it occurs in the western U.S. are large and include: decreased densities of native macroinvertebrates and reduced food resources; decreased whole-stream algal production; poor food source in that mudsnails are much more difficult to digest, with their hard shells and operculum than are the thin-shelled, native pulmonate snails that do not have opercula or than soft-bodied, aquatic insect larvae.

Guideline Reference:

The New Zealand Mudsnail Invades the Western United States. Aquatic Nuisance Species Digest Volume 4 No. 4.

Spatial Representation:

10 sites were sampled in the following locations in Las Virgenes Creek: end of Las Virgenes Rd; SMMC open space; open space in the 2nd crossing W of L.V. Creek; dead end of Las Virgenes Rd. gate on right side; Lost Hills Rd. Bridge at the Starbucks parking lot; Apartments upstream of RCD Stream Restoration; RCD Stream Restoration site on Lost Hills Rd; DeAnza Park, on the path down to creek; White Oak Farms Bridge; Upstream Crags Rd. crossing MCSP; D.S.

Temporal Representation:

Five sites were sampled in July of 2006 and the additional five sites were sampled in July of 2007 and October of 2008.

Environmental Conditions:

QAPP Information:

Data was collected as detailed in the Santa Monica Bay Restoration Commission and Santa Monica Baykeeper New Zealand Mudsnail Surveys.

QAPP Information Reference(s):

New Zealand Mudsnail Surveys July 2006, July 2007 and October 2008 Santa Monica Mountains. Santa Monica Bay Restoration Commission / Santa Monica Baykeeper.


DECISION ID	16621	Region 4
Las Virgenes Creek

Pollutant:	Invasive Species
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	Nonpoint Source \| Point Source
Expected TMDL Completion Date:	2021
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.10 of the Listing Policy. Under section 3.10, waters are listed when a declining trend in water quality is substantiated. Three lines of evidence are available in the administrative record to assess this pollutant. Three of 5 sites showed an increase in density of mud snails over the three years of sampling (2006, 2007, 2008) and 6 out of 10 sites sampled showed medium or high densities of mud snail in 2008. At high numbers, mud snails can completely cover a stream bed and damage local stream ecosystems. The colonies outcompete native aquatic invertebrates that the watersheds fish and amphibians rely on for food, disrupting the entire food web. Benthic macroinvertebrates as measured by Southern California IBI (index of biological integrity) in Las Virgenes Creek were poor or very poor in 2005 indicating impairment of benthic community structure. 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 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. Data was collected over a three years time frame and a baseline condition of zero abundance of the invasive species was used. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

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:

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 16621, Invasive Species	Region 4
Las Virgenes Creek

LOE ID:

28703

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Fish Migration | Fish Spawning | Preservation of Rare & Endangered Species | Wetland Habitat | Wildlife Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Data Reference:

New Zealand Mudsnail Surveys July 2006, July 2007 and October 2008 Santa Monica Mountains. Santa Monica Bay Restoration Commission / Santa Monica Baykeeper.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

The New Zealand Mudsnail Invades the Western United States. Aquatic Nuisance Species Digest Volume 4 No. 4.

Spatial Representation:

Temporal Representation:

Five sites were sampled in July of 2006 and the additional five sites were sampled in July of 2007 and October of 2008.

Environmental Conditions:

QAPP Information:

Data was collected as detailed in the Santa Monica Bay Restoration Commission and Santa Monica Baykeeper New Zealand Mudsnail Surveys.

QAPP Information Reference(s):

New Zealand Mudsnail Surveys July 2006, July 2007 and October 2008 Santa Monica Mountains. Santa Monica Bay Restoration Commission / Santa Monica Baykeeper.

Line of Evidence (LOE) for Decision ID 16621, Invasive Species	Region 4
Las Virgenes Creek

LOE ID:

30175

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Fish Migration | Fish Spawning | Preservation of Rare & Endangered Species | Wetland Habitat | Wildlife Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

The IBI scores at these sites ranked in the very poor and poor range (12 and 25) in the spring and poor and very poor range (11 and 23) in the fall.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

A Quantitative Tool for Assessing the Integrity of Southern Coastal California Streams. Appendix 7-B Environmental Management Vol. 35, No. 4, pp. 493-504.

Spatial Representation:

Two sites in Las Virgenes Creek were sampled, LV1 at 34° 10.108' N 118° 42.155' W and LV2 at 34° 07.507' N 118° 42.494' W

Temporal Representation:

Sites were sampled in Spring and Fall of 2005

Environmental Conditions:

Benthic macroinvertebrate populations and IBI scores may also be affected by a wide range of anthropogenic stressors.

QAPP Information:

Data was collected in compliance with California Stream Bioassessment Procedure.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 16621, Invasive Species	Region 4
Las Virgenes Creek

LOE ID:

30174

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Fish Migration | Fish Spawning | Preservation of Rare & Endangered Species | Wetland Habitat | Wildlife Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Two sites sampled in 2005 IBI scores were calculated at 17 category very poor and 34, category poor.

Data Reference:

Malibu Bioassessment Winter 2005

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

A Quantitative Tool for Assessing the Integrity of Southern Coastal California Streams. Appendix 7-B Environmental Management Vol. 35, No. 4, pp. 493-504.

Spatial Representation:

Two sites in Las Virgenes Creek were sampled, LV5 and LV9.

Temporal Representation:

Sites were sampled in winter of 2005.

Environmental Conditions:

Benthic macroinvertebrate populations and IBI scores may also be affected by a wide range of anthropogenic stressors.

QAPP Information:

Data was collected in compliance with California Stream Bioassessment Procedure. Collection procedures were audited by California Department of Fish and Game in 2006.

QAPP Information Reference(s):

California Stream Bioassessment Procedure Biological and Physical Habitat Field Audit


DECISION ID	7059	Region 4
Las Virgenes Creek

Pollutant:	Nutrients (Algae)
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:	Agriculture-animal \| Atmospheric Deposition \| Golf course activities \| Groundwater Loadings \| Irrigated Crop Production \| Major Municipal Point Source-dry and/or wet weather discharge \| Onsite Wastewater Systems (Septic Tanks) \| Urban Runoff/Storm Sewers
TMDL Name:	Malibu Creek Nutrients (50)
TMDL Project Code:	239
Date TMDL Approved by USEPA:	03/21/2003
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 established 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 established 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 7059, Nutrients (Algae)	Region 4
Las Virgenes Creek

LOE ID:

28587

Pollutant:

Nutrients (Algae)

LOE Subgroup:

Narrative Description Data

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:

A TMDL has been established for this water segment-pollutant combination. The Malibu Creek Watershed Nutrient TMDL was established by USEPA on March 21, 2003.

Data Reference:

Staff report, appendix, and letter to SWRCB and Los Angeles RWQCB establishing a TMDL for Nutrients in the Malibu Creek Watershed.

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 7059, Nutrients (Algae)	Region 4
Las Virgenes Creek

LOE ID:

3882

Pollutant:

Nutrients (Algae)

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 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	7108	Region 4
Las Virgenes Creek

Pollutant:	Organic Enrichment/Low Dissolved Oxygen
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:	Agriculture-animal \| Atmospheric Deposition \| Golf course activities \| Groundwater Loadings \| Irrigated Crop Production \| Major Municipal Point Source-dry and/or wet weather discharge \| Onsite Wastewater Systems (Septic Tanks) \| Urban Runoff/Storm Sewers
TMDL Name:	Malibu Creek Nutrients (50)
TMDL Project Code:	239
Date TMDL Approved by USEPA:	03/21/2003
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 established 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 established 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 7108, Organic Enrichment/Low Dissolved Oxygen	Region 4
Las Virgenes Creek

LOE ID:

3883

Pollutant:

Organic Enrichment/Low Dissolved Oxygen

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 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 7108, Organic Enrichment/Low Dissolved Oxygen	Region 4
Las Virgenes Creek

LOE ID:

28602

Pollutant:

Organic Enrichment/Low Dissolved Oxygen

LOE Subgroup:

Narrative Description Data

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:

A TMDL has been established for this water segment-pollutant combination. The Malibu Creek Watershed Nutrient TMDL was established by USEPA on March 21, 2003.

Data Reference:

Staff report, appendix, and letter to SWRCB and Los Angeles RWQCB establishing a TMDL for Nutrients in the Malibu Creek Watershed.

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	7109	Region 4
Las Virgenes Creek

Pollutant:	Scum/Foam-unnatural
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:	Agriculture-animal \| Atmospheric Deposition \| Golf course activities \| Groundwater Loadings \| Irrigated Crop Production \| Major Municipal Point Source-dry and/or wet weather discharge \| Onsite Wastewater Systems (Septic Tanks) \| Urban Runoff/Storm Sewers
TMDL Name:	Malibu Creek Nutrients (50)
TMDL Project Code:	239
Date TMDL Approved by USEPA:	03/21/2003
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 established 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 established 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 7109, Scum/Foam-unnatural	Region 4
Las Virgenes Creek

LOE ID:

3884

Pollutant:

Scum/Foam-unnatural

LOE Subgroup:

Pollutant-Nuisance

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:

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

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 7109, Scum/Foam-unnatural	Region 4
Las Virgenes Creek

LOE ID:

28597

Pollutant:

Scum/Foam-unnatural

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 established for this water segment-pollutant combination. The Malibu Creek Watershed Nutrient TMDL was established by USEPA on March 21, 2003.

Data Reference:

Staff report, appendix, and letter to SWRCB and Los Angeles RWQCB establishing a TMDL for Nutrients in the Malibu Creek Watershed.

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	5377	Region 4
Las Virgenes Creek

Pollutant:	Sulfates
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)(2006)
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. An insufficient total number of samples were taken and an insufficient number of samples exceed the MCL guideline for Sulfate. Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification in favor of 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.Two of Two samples exceeded the MCL guideline. More data is needed to determine if the water quality standard is exceeded. 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:	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 5377, Sulfates	Region 4
Las Virgenes Creek

LOE ID:

2259

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:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Two samples with two exceeding. (SWAMP, 2004).

Data Reference:

Placeholder reference 2006 303(d)

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

CCR- Title 22 Table 64449-B Secondary Maximum Contaminant Levels of 250 mg/l for Sulfate.

Objective/Criterion Reference:

Placeholder reference 2006 303(d)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station at Las Virgenes Creek:34.09732 -118.72087.

Temporal Representation:

Samples were collected March 2003 through March 2004.

Environmental Conditions:

Malibu Creek Watershed: 404.22

QAPP Information:

SWAMP Quality Assurance Plan.

QAPP Information Reference(s):


DECISION ID	7110	Region 4
Las Virgenes Creek

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:	Source Unknown
Expected TMDL Completion Date:	2019
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.

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 7110, Sedimentation/Siltation	Region 4
Las Virgenes Creek

LOE ID:

3885

Pollutant:

Sedimentation/Siltation

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 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	7112	Region 4
Las Virgenes Creek

Pollutant:	Selenium
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:	Nonpoint Source
Expected TMDL Completion Date:	2019
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.

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 7112, Selenium	Region 4
Las Virgenes Creek

LOE ID:

3886

Pollutant:

Selenium

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 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	7113	Region 4
Las Virgenes Creek

Pollutant:	Trash
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:	Nonpoint Source
Expected TMDL Completion Date:	2019
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.

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 7113, Trash	Region 4
Las Virgenes Creek

LOE ID:

3887

Pollutant:

Trash

LOE Subgroup:

Visual

Matrix:

Not Specified

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	6156	Region 4
Las Virgenes Creek

Pollutant:	Coliform Bacteria
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:	Malibu Pathogens (47 in part)
TMDL Project Code:	236
Date TMDL Approved by USEPA:	01/01/2005
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 approved by USEPA and an approved implementation plan is expected to result in attainment of the standard. The Malibu Creek Watershed Bacteria TMDL was approved by USEPA in January of 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 6156, Coliform Bacteria	Region 4
Las Virgenes Creek

LOE ID:

2260

Pollutant:

Coliform Bacteria

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Water 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 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):