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

Supporting Information

Regional Board 9 - San Diego Region

Water Body Name:	Prima Deshecha Creek
Water Body ID:	CAR9013000020010924090843
Water Body Type:	River & Stream


DECISION ID	76839	Region 9
Prima Deshecha Creek

Pollutant:	Nickel
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Delist from 303(d) list (TMDL required list)(2016)
Revision Status	Original
Reason for Delisting:	Flaws in original listing
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 of the Listing Policy. The original line of evidence from 2010 (LOE 7740) was incorrectly calculated the LOE should reflect one exceedance out of ten samples. LOE 95955 replaces the flawed LOE7740 which will be retired from the system. Under section 3.1 of the Listing Policy a single line of evidence is necessary to assess listing status. Two lines of evidence is available in the administrative record to assess this pollutant. One of the nineteen samples exceed the water quality objective for nickel. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for removing this water segment-pollutant combination from the CWA section 303(d) List because the basis for the original listing in 2010 was flawed. 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. 3. Three of 35 samples exceed the cadmium water quality objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be removed from the section 303(d) list because applicable water quality standards for the pollutant are not being exceeded.

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 76839, Nickel	Region 9
Prima Deshecha Creek

LOE ID:

7740

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical monitoring (conventional pollutants only)

Data Used to Assess Water Quality:

Three out of eight samples collected exceed the hardness adjusted Criterion Continuous Concentration for dissolved nickel according to results in the Orange County Stormwater Annual Progress Reports from 2002 through 2006. Samples were collected from December 2002 through March 2006.

Data Reference:

Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

From the CTR, the dissolved nickel Criterion Continuous Concentration is 52 ppb and the Criterion Maximum Concentration is 470 ppb, but these criteria vary depending upon hardness of the sample (U.S. EPA, 2000).

Objective/Criterion Reference:

Water Quality Standards; Establishment of Numeric Criteria for Priority Toxic Pollutants for the State of California; Rule. 40 CFR Part 131. U.S. Environmental Protection Agency, Region IX, Water Division, San Francisco, CA

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at the mass loading station in Prima Deschecha Creek at 33.44679°, 117.64448°.

Temporal Representation:

Samples were collected from December 2002 through March 2006.

Environmental Conditions:

Samples were collected during wet weather.

QAPP Information:

QA/QC conducted according to Federal Regulations under requirements of a NPDES permit.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 76839, Nickel	Region 9
Prima Deshecha Creek

LOE ID:

95955

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

One of the 10 samples exceeded the hardness adjusted water quality criterion for nickel.

Data Reference:

Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. Inland surface waters, enclosed bays, and estuaries shall not contain toxic pollutants in excess of the numerical objectives applicable to California specified in 40 CFR 131.36 (section 131.36 revised at 57 FR 60848, December 22, 1992).

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The dissolved criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion. If no hardness data were available, a value of 100 mg/L was used.

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected at the mass loading station in Prima Deschecha Creek at 33.44679°, 117.64448°.

Temporal Representation:

Samples were collected from December 2002 through March 2006.

Environmental Conditions:

QAPP Information:

Samples were collected and analyzed in accordance with the signed and certified, Quality Assurance Management Plan for the Orange County Stormwater Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for the Orange County Stormwater Program.

Line of Evidence (LOE) for Decision ID 76839, Nickel	Region 9
Prima Deshecha Creek

LOE ID:

75495

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the 9 samples exceeded the hardness adjusted water quality criterion for nickel.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from Prima Deshecha Channel at Calle Grande Vista from stations PD-CGV and PDCM01.

Temporal Representation:

The sample was collected from PD-CGV on 4/17/2007. Samples were collected from PDCM01 intermittently from November 2006 through February 2009.

Environmental Conditions:

The sample collected from PD-CGV is representative of dry weather conditions. The remaining 96% of the samples collected from PDCM01 were collected after storm events.

QAPP Information:

Samples were collected and analyzed in accordance with the signed and certified, Quality Assurance Management Plan for the Orange County Stormwater Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for the Orange County Stormwater Program.


DECISION ID	71122	Region 9
Prima Deshecha Creek

Pollutant:	Cadmium
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)(2016)
Revision Status	Original
Sources:	A Source Unknown
Expected TMDL Completion Date:	2021
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the section 303(d) list under section 4.1 of the Listing Policy. Under section 4.1 a single line of evidence is necessary to assess listing status. Two lines of evidence is available in the administrative record to assess this pollutant. 12 of the 17 samples exceed the water quality objective for cadmium. 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 CWA 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. 3. 12 of 17 samples exceed the cadmium water quality objective and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy. 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.

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 71122, Cadmium	Region 9
Prima Deshecha Creek

LOE ID:

75482

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Four of the 9 samples exceeded the hardness adjusted water quality criterion for cadmium.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from Prima Deshecha Channel at Calle Grande Vista from stations PD-CGV and PDCM01.

Temporal Representation:

The sample was collected from PD-CGV on 4/17/2007. Samples were collected from PDCM01 intermittently from November 2007 through February 2009.

Environmental Conditions:

The sample collected from PD-CGV is representative of dry weather conditions. The remaining 96% of the samples collected from PDCM01 were collected after storm events.

QAPP Information:

Samples were collected and analyzed in accordance with the signed and certified, Quality Assurance Management Plan for the Orange County Stormwater Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 71122, Cadmium	Region 9
Prima Deshecha Creek

LOE ID:

75512

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Six samples were collected to test for toxicity. Three of the six samples exhibited statistically and biologically significant toxicity. The toxicity tests that exhibited significant toxicity included Purple Urchin fertilization and Mysid survival and biomass.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Toxicity is defined as a statistically significant effect in the sample exposure compared to the control using EPA-recommended hypothesis testing. The t-test is used to determine if there is a statistically significant decrease in organism response in the sample as compared to the control. Additionally, the biological significance of the sample was evaluated by determining whether the sample response was lower than the evaluation threshold.

Guideline Reference:

Quality Assurance Project Plan for Acute and Chronic Invertebrate and Fish Toxicity Testing in the Sacramento-San Joaquin Delta.

Spatial Representation:

The sample was collected at station PDCM01 Prima Deshecha Channel.

Temporal Representation:

The sample was collected from November 2006 to February 2009.

Environmental Conditions:

QAPP Information:

The data collected under the Quality Assurance Management Plan for The Orange County Stormwater Program. The SWAMP measurement quality objectives were followed for toxicity data. The performance of toxicity bioassays and evaluation of reference toxicants were performed using USEPA and Standard Methods.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 71122, Cadmium	Region 9
Prima Deshecha Creek

LOE ID:

7739

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical monitoring (conventional pollutants only)

Data Used to Assess Water Quality:

Three out of eight samples collected exceed the hardness adjusted Criterion Maximum Concentration for dissolved cadmium. All eight of the samples collected exceed hardness adjusted Criterion Continuous Concentration for dissolved cadmium according to results in the Orange County Stormwater Progress Reports from 2002-2006.

Data Reference:

Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

From the CTR, the dissolved cadmium Criterion Continuous Concentration is 2.2 ppb and the Criterion Maximum Concentration is 4.3 ppb, but these criteria may vary depending upon hardness of the sample (U.S. EPA, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at the mass loading station in Prima Deschecha Creek at 33.44679°, 117.64448°.

Temporal Representation:

Samples were collected from December 2002 through March 2006.

Environmental Conditions:

Samples were collected during Wet Weather.

QAPP Information:

QA/QC conducted according to Federal Regulations under requirements of a NPDES permit.

QAPP Information Reference(s):


DECISION ID	69188	Region 9
Prima Deshecha Creek

Pollutant:	Phosphorus
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)(2016)
Revision Status	Original
Sources:	A Source Unknown
Expected TMDL Completion Date:	2019
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the section 303(d) list under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Fifty of samples exceeded the water quality objective for total phosphorus. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for 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 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. Fifty of 59 samples exceeded the total phoshorus water quality objective and this does not exceed the allowable frequency listed in Table 4.1 of the Listing Policy. 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:	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 cycle. 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 69188, Phosphorus	Region 9
Prima Deshecha Creek

LOE ID:

7742

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical monitoring (conventional pollutants only)

Data Used to Assess Water Quality:

Four of five flow-weighted event mean concentrations exceeded the water quality objective according to results in the Orange County Stormwater Annual Progress Reports from 2002 through 2006. Samples were collected from December 2002 through March 2006.

Data Reference:

Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at the mass loading station in Prima Deschecha Creek at 33.44679°, 117.64448°.

Temporal Representation:

Samples were collected from December 2002 through March 2006.

Environmental Conditions:

Samples were collected during wet weather.

QAPP Information:

QA/QC conducted according to Federal Regulations under requirements of a NPDES permit.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 69188, Phosphorus	Region 9
Prima Deshecha Creek

LOE ID:

3011

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Agricultural Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data were collected by Orange County in 1997-2000. Forty-six of 54 samples were in exceedance.

Data Reference:

Placeholder reference 2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

From the Basin Plan: For inland surface waters - streams and other flowing waters and all beneficial uses, the WQO for total phosphorus is 0.1 mg/L. This appears to be the desired goal in order to prevent plant nuisance in streams and other flowing waters; not to be exceeded more than 10% of the time.

Objective/Criterion Reference:

Placeholder reference 2006 303(d)

Evaluation Guideline:

Use unless studies of the specific water body in question clearly show that water quality objective changes are permissible and changes are approved by the Regional Board.

Guideline Reference:

Placeholder reference 2006 303(d)

Spatial Representation:

Samples were collected at Prima Deshecha Creek. Exact location was not reported.

Temporal Representation:

Samples were collected 1-5 times per month from 07/02/1997 to 06/29/2000. At least 4 months per year were represented.

Environmental Conditions:

QAPP Information:

Data used in 2002 assessment.

QAPP Information Reference(s):


DECISION ID	77792	Region 9
Prima Deshecha Creek

Pollutant:	Turbidity
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)(2016)
Revision Status	Original
Sources:	A Source Unknown
Expected TMDL Completion Date:	2019
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the section 303(d) list under section 4.2 of the Listing Policy. Under section 4.2 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. Forty of 54 samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against 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 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. Forty of 54 samples were in exceedance of the turbidity water quality objective and this exceeds the allowable frequency listed in Table 4.2 of the Listing Policy. 4. 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:	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 cycle. 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 77792, Turbidity	Region 9
Prima Deshecha Creek

LOE ID:

3010

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Agricultural Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data were collected by Orange County from 1997-2000. Forty of 54 samples were in exceedance. Turbidity concentrations ranged from 4.0 to 5400. There was no note of weather events to correspond with changing turbidity levels.

Data Reference:

Placeholder reference 2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

From the Basin Plan: For inland surface waters and all beneficial uses, the WQO for turbidity is 20 NTU. This concentration is not to be exceeded more than 10% of the time during any one year period.

Objective/Criterion Reference:

Placeholder reference 2006 303(d)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at Prima Deshecha Channel.

Temporal Representation:

Samples were collected 1-5 times per month from 07/02/1997 to 06/29/2000. Data was reported for at least four months of each year.

Environmental Conditions:

QAPP Information:

Data used in 2002 assessment.

QAPP Information Reference(s):


DECISION ID	82303	Region 9
Prima Deshecha Creek

Pollutant:	Ammonia
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line(s) of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. One of the seven samples exceed the objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA 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. One of seven samples exceeded the objective and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

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 82303, Ammonia	Region 9
Prima Deshecha Creek

LOE ID:

75496

Pollutant:

Ammonia (Unionized)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

One of seven averaged samples exceeded the water quality objective for unionized ammonia. Samples were reported as as total ammonia as nitrogen and were converted to unionized ammonia as nitrogen before being compared with the objective. One averaged sample for 11/27/06 measured at 2.88 mg/L as total ammonia as nitrogen was not counted because it did not have corresponding pH and temperature data. The single exceedance was calculated at 1.18 mg/L as N for total ammonia at pH 8 and 14.66 degrees C which converts to 0.031 mg/L as N of unionized ammonia.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at Calle Grande Vista.

Temporal Representation:

Samples were collected from April 2007 to February 2009.

Environmental Conditions:

QAPP Information:

A signed QAPP was included with the stated goal of ensuring the consistent collection of accurate water quality information that will used to satisfy the objectives of the Orange County Stormwater Program.

QAPP Information Reference(s):


DECISION ID	82304	Region 9
Prima Deshecha Creek

Pollutant:	Arsenic
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Zero of 9 samples exceed the criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 9 samples exceeded the criterion and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

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 82304, Arsenic	Region 9
Prima Deshecha Creek

LOE ID:

75501

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the 9 samples exceeded the water quality criteria for arsenic.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The CTR for arsenic is 150 ug/L.

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from Prima Deshecha Channel at Calle Grande Vista from stations PD-CGV and PDCM01.

Temporal Representation:

The sample was collected from PD-CGV on 4/17/2007. Samples were collected from PDCM01 intermittently from November 2007 through February 2009.

Environmental Conditions:

The sample collected from PD-CGV is representative of dry weather conditions. The remaining 96% of the samples collected from PDCM01 were collected after storm events.

QAPP Information:

Samples were collected and analyzed in accordance with the signed and certified, Quality Assurance Management Plan for the Orange County Stormwater Program.

QAPP Information Reference(s):


DECISION ID	82357	Region 9
Prima Deshecha Creek

Pollutant:	Chlorpyrifos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Zero of the 21 samples exceed the criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 21 samples exceeded the criterion and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. However, the data cannot be used as primary evidence for use support determination. 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

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 82357, Chlorpyrifos	Region 9
Prima Deshecha Creek

LOE ID:

75484

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Zero of twenty-one samples exceeded the continuous concentration (four day average) for chlorpyrifos in freshwater of 14.0 ng/L. However, 4 samples were collected with a reporting limit above the objective and could not be used in the assessment.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall be present in the water column, sediments or biota at concentration(s) that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

The Criteria Continuous Concentration (four day average) for chlorpyrifos in freshwater is 14.0 ng/L.

Guideline Reference:

Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game

Spatial Representation:

Samples were collected at Prima Deshecha Creek, site PDCM01

Temporal Representation:

Samples were collected from 2006 through 2009.

Environmental Conditions:

According to the County of Orange Stormwater Program Quality Assurance Management Plan (QAMP) dated January 2010, samples were collected during the dry season and storm events.

QAPP Information:

Data were submitted with the County of Orange Stormwater Program Quality Assurance Management Plan (QAMP) dated January 2010. The Regional Water Board has determined that equivalent QA/QC documentation exists within the Water Quality Monitoring and Reporting Program for the Orange County MS4 permit and appendix C-11- X of the 2008-09 monitoring report.

QAPP Information Reference(s):


DECISION ID	82305	Region 9
Prima Deshecha Creek

Pollutant:	Chromium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Zero of the nine samples exceed the criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 9 samples exceeded the criterion and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

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 82305, Chromium	Region 9
Prima Deshecha Creek

LOE ID:

75485

Pollutant:

Chromium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the nine samples exceeded the hardness adjusted water quality criterion for chromium.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from Prima Deshecha Channel at Calle Grande Vista from stations PD-CGV and PDCM01.

Temporal Representation:

The sample was collected from PD-CGV on 4/17/2007. Samples were collected from PDCM01 intermittently from November 2007 through February 2009.

Environmental Conditions:

The sample collected from PD-CGV is representative of dry weather conditions. The remaining 96% of the samples collected from PDCM01 were collected after storm events.

QAPP Information:

Samples were collected and analyzed in accordance with the signed and certified, Quality Assurance Management Plan for the Orange County Stormwater Program.

QAPP Information Reference(s):


DECISION ID	82356	Region 9
Prima Deshecha Creek

Pollutant:	Copper
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Zero of the nine samples exceed the criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 9 samples exceeded the criterion and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

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 82356, Copper	Region 9
Prima Deshecha Creek

LOE ID:

75486

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the nine samples exceeded the hardness adjusted water quality criterion for copper.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from Prima Deshecha Channel at Calle Grande Vista from stations PD-CGV and PDCM01.

Temporal Representation:

The sample was collected from PD-CGV on 4/17/2007. Samples were collected from PDCM01 intermittently from November 2007 through February 2009.

Environmental Conditions:

The sample collected from PD-CGV is representative of dry weather conditions. The remaining 96% of the samples collected from PDCM01 were collected after storm events.

QAPP Information:

Samples were collected and analyzed in accordance with the signed and certified, Quality Assurance Management Plan for the Orange County Stormwater Program.

QAPP Information Reference(s):


DECISION ID	82384	Region 9
Prima Deshecha Creek

Pollutant:	Diazinon
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Zero of the eight samples exceed the criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 8 samples exceeded the criterion and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

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 82384, Diazinon	Region 9
Prima Deshecha Creek

LOE ID:

75487

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical monitoring (conventional pollutants only)

Data Used to Assess Water Quality:

None of eight samples exceed the continuous concentration for Diazinon criteria of 0.1 ug/L.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall be present in the water column, sediments or biota at concentration(s) that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (Finlayson, 2004).

Guideline Reference:

Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game

Spatial Representation:

Samples were collected at Prima Deshecha Creek, site PDCM01

Temporal Representation:

Samples were collected from 2006 through 2009.

Environmental Conditions:

According to the County of Orange Stormwater Program Quality Assurance Management Plan (QAMP) dated January 2010, samples were collected during the dry season and storm events.

QAPP Information:

Data were submitted with the County of Orange Stormwater Program Quality Assurance Management Plan (QAMP) dated January 2010. However, data were collected prior to the development of this QAMP, therefore the quality of these data are unknown.

QAPP Information Reference(s):


DECISION ID	82358	Region 9
Prima Deshecha Creek

Pollutant:	Lead
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Zero of the nine samples exceed the criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 9 samples exceeded the criterion and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

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 82358, Lead	Region 9
Prima Deshecha Creek

LOE ID:

75492

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the 9 samples exceeded the hardness adjusted water quality criterion for lead.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from Prima Deshecha Channel at Calle Grande Vista from stations PD-CGV and PDCM01.

Temporal Representation:

The sample was collected from PD-CGV on 4/17/2007. Samples were collected from PDCM01 intermittently from November 2007 through February 2009.

Environmental Conditions:

The sample collected from PD-CGV is representative of dry weather conditions. The remaining 96% of the samples collected from PDCM01 were collected after storm events.

QAPP Information:

Samples were collected and analyzed in accordance with the signed and certified, Quality Assurance Management Plan for the Orange County Stormwater Program.

QAPP Information Reference(s):


DECISION ID	77288	Region 9
Prima Deshecha Creek

Pollutant:	Mercury
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, one line of evidence are necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero of the one sample exceed the criteria for mercury. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA 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. Zero of the one sample exceed the criteria for mercury and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to [SECTION 3.11/4.11] of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

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 77288, Mercury	Region 9
Prima Deshecha Creek

LOE ID:

75494

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Zero of one samples exceeded the water quality criteria for mercury.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

National Recommended Water Quality Criterion Continuous Concentrations (4-day average concentrations) for freshwater aquatic organisms exposure to elemental mercury is 0.77 ug/L.

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from Prima Deshecha Channel at PDCM01.

Temporal Representation:

Samples were collected from PDCM01 on November 4, 2008

Environmental Conditions:

The sample was collected in wet weather.

QAPP Information:

Samples were collected and analyzed in accordance with the signed and certified, Quality Assurance Management Plan for the Orange County Stormwater Program.

QAPP Information Reference(s):


DECISION ID	82409	Region 9
Prima Deshecha Creek

Pollutant:	Oxygen, Dissolved
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line(s) of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Zero of the eight samples exceed the objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA 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. Zero of eight samples exceeded the objective and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 26 samples is needed to determine if a beneficial use is fully supported using table 3.2. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

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 82409, Oxygen, Dissolved	Region 9
Prima Deshecha Creek

LOE ID:

75497

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Zero of 8 samples exceeded the objective.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved oxygen content of all surface waters designated as "Warm Freshwater Habitat" must be greater than 5.0 mg/L. The annual mean dissolved oxygen concentration shall not be less than 7 mg/l more than 10% of the time.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the PD-CGV and PDCM01 stations.

Temporal Representation:

Samples were collected approximately four times per semi-annual period from April 2007 to February 2009.

Environmental Conditions:

QAPP Information:

Samples were collected and analyzed in accordance with the signed and certified, Quality Assurance Management Plan for the Orange County Stormwater Program.

QAPP Information Reference(s):


DECISION ID	82545	Region 9
Prima Deshecha Creek

Pollutant:	Silver
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Zero of the nine samples exceed the criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 9 samples exceeded the criterion and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

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 82545, Silver	Region 9
Prima Deshecha Creek

LOE ID:

75500

Pollutant:

Silver

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the nine samples exceeded the hardness adjusted water quality criterion for silver.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

California Toxics Rule (CTR) lists criterion maximum concentrations for silver to protect aquatic life in freshwater (1-hour average). The dissolved silver criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion. If no hardness data were available, a value of 100 mg/L was used.

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from Prima Deshecha Channel at Calle Grande Vista from stations PD-CGV and PDCM01.

Temporal Representation:

The sample was collected from PD-CGV on 4/17/2007. Samples were collected from PDCM01 intermittently from November 2007 through February 2009.

Environmental Conditions:

The sample collected from PD-CGV is representative of dry weather conditions. The remaining 96% of the samples collected from PDCM01 were collected after storm events.

QAPP Information:

Samples were collected and analyzed in accordance with the signed and certified, Quality Assurance Management Plan for the Orange County Stormwater Program.

QAPP Information Reference(s):


DECISION ID	82598	Region 9
Prima Deshecha Creek

Pollutant:	Zinc
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Zero of the nine samples exceed the criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 9 samples exceeded the criterion and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

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 82598, Zinc	Region 9
Prima Deshecha Creek

LOE ID:

75513

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

None of the nine samples exceeded the hardness adjusted water quality criterion for zinc.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from Prima Deshecha Channel at Calle Grande Vista from stations PD-CGV and PDCM01.

Temporal Representation:

The sample was collected from PD-CGV on 4/17/2007. Samples were collected from PDCM01 intermittently from November 2007 through February 2009.

Environmental Conditions:

The sample collected from PD-CGV is representative of dry weather conditions. The remaining 96% of the samples collected from PDCM01 were collected after storm events.

QAPP Information:

Samples were collected and analyzed in accordance with the signed and certified, Quality Assurance Management Plan for the Orange County Stormwater Program.

QAPP Information Reference(s):


DECISION ID	82599	Region 9
Prima Deshecha Creek

Pollutant:	pH
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line(s) of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. One of the 20 samples exceed the objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA 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. One of 20 samples exceeded the objective and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 26 samples is needed to determine if a beneficial use is fully supported using table 3.2. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

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 82599, pH	Region 9
Prima Deshecha Creek

LOE ID:

75498

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Numeric data generated from 20 minimums and maximums of pH data had 1 exceedence.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH of all inland surface waters shall not be depressed below 6.5 or raised above 8.5 as a result of waste discharges.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the PD-CGV and PDCM01 stations.

Temporal Representation:

Samples were collected approximately once a month from April 2007 to November 2009.

Environmental Conditions:

QAPP Information:

NPDES quality assurance.

QAPP Information Reference(s):


DECISION ID	82411	Region 9
Prima Deshecha Creek

Pollutant:	Indicator Bacteria
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)(2016)
Revision Status	Original
Sources:	A Source Unknown
Expected TMDL Completion Date:	2027
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. 14 of the 14 samples exceed the objective for enterococcus. 12 of 14 samples exceed the objective for fecal coliform. 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 CWA 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. 14 of 14 and12 of 14samples exceed the objectives for indicator bacteria and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 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:	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:	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 82411, Indicator Bacteria	Region 9
Prima Deshecha Creek

LOE ID:

75490

Pollutant:

Fecal Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Twelve of the fourteen samples exceeded the fecal coliform objective.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The single sample feal coliform concentration shall not exceed more than 400/100ml. Region 9 Basin Plan.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected from site PDCM01, Prima Deshecha Channel at Calle Grande Vista.

Temporal Representation:

The samples were collected from April 2007 to February 2009.

Environmental Conditions:

QAPP Information:

The samples were collected and analyzed under the Quality Assurance Management Plan for The Orange County Stormwater Program. Mass Emissions Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 82411, Indicator Bacteria	Region 9
Prima Deshecha Creek

LOE ID:

75489

Pollutant:

Enterococcus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The one geomean exceeded the enterococcus objective.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The geometric mean enterococcus concentration shall not exceed more than 33/100ml. Ambient Water Quality Criteria USEPA. Water Quality Control Plan for the San Diego Basin.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected from site PDCM01, Prima Deshecha Channel at Calle Grande Vista.

Temporal Representation:

The samples were collected from April 2007 to February 2009.

Environmental Conditions:

QAPP Information:

The samples were collected and analyzed under the Quality Assurance Management Plan for The Orange County Stormwater Program. Mass Emissions Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 82411, Indicator Bacteria	Region 9
Prima Deshecha Creek

LOE ID:

75488

Pollutant:

Enterococcus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Fourteen of the fourteen samples exceeded the enterococcus objective.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The single sample enterococcus concentration shall not exceed more than 61/100ml. Ambient Water Quality Criteria USEPA. Region 9 Basin Plan.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected from site PDCM01, Prima Deshecha Channel at Calle Grande Vista.

Temporal Representation:

The samples were collected from April 2007 to February 2009.

Environmental Conditions:

QAPP Information:

The samples were collected and analyzed under the Quality Assurance Management Plan for The Orange County Stormwater Program. Mass Emissions Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 82411, Indicator Bacteria	Region 9
Prima Deshecha Creek

LOE ID:

75491

Pollutant:

Fecal Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

The one geomean exceeded the fecal coliform objective.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The geometric mean feal coliform concentration shall not exceed more than 200/100ml. Water Quality Control PLan for the San Diego Basin.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected from site PDCM01, Prima Deshecha Channel at Calle Grande Vista.

Temporal Representation:

The samples were collected from April 2007 to February 2009.

Environmental Conditions:

QAPP Information:

The samples were collected and analyzed under the Quality Assurance Management Plan for The Orange County Stormwater Program. Mass Emissions Monitoring Program.

QAPP Information Reference(s):


DECISION ID	82408	Region 9
Prima Deshecha Creek

Pollutant:	Malathion
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)(2016)
Revision Status	Original
Sources:	A Source Unknown
Expected TMDL Completion Date:	2027
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Four of the eight samples exceed the evaluation guideline for malathion. Three of six samples exhibited toxicity. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for placing this water segment-pollutant combination on the CWA 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. Four of eight samples exceeded the evaluation guideline for malathion, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 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:	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:	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 82408, Malathion	Region 9
Prima Deshecha Creek

LOE ID:

75512

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Quality Assurance Project Plan for Acute and Chronic Invertebrate and Fish Toxicity Testing in the Sacramento-San Joaquin Delta.

Spatial Representation:

The sample was collected at station PDCM01 Prima Deshecha Channel.

Temporal Representation:

The sample was collected from November 2006 to February 2009.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 82408, Malathion	Region 9
Prima Deshecha Creek

LOE ID:

75493

Pollutant:

Malathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical monitoring (conventional pollutants only)

Data Used to Assess Water Quality:

Four of eight samples exceed the continuous chronic concentration for Malathion in freshwater of 100 ng/L. (0.1 ug/L)

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall be present in the water column, sediments or biota at concentration(s) that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

The maximum (Instantaneous) concentration for Malathion in freshwater is 100 ng/L.

Guideline Reference:

Quality Criteria for Water. USEPA Office of Water and Hazardous Materials. Washington, D.C

Spatial Representation:

Twenty five samples were collected at Prima Deshecha Creek, site PDCM01

Temporal Representation:

Samples were collected from 2006 through 2009.

Environmental Conditions:

According to the County of Orange Stormwater Program Quality Assurance Management Plan (QAMP) dated January 2010, samples were collected during the dry season and storm events.

QAPP Information:

QAPP Information Reference(s):


DECISION ID	77285	Region 9
Prima Deshecha Creek

Pollutant:	Nitrogen
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)(2016)
Revision Status	Original
Sources:	A Source Unknown
Expected TMDL Completion Date:	2023
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Eight of nine samples (collected in both dry and wet conditions) exceed the OBJECTIVE. 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 CWA 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 of nine samples (collected in both dry and wet conditions) exceed the OBJECTIVE and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 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:	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:	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 77285, Nitrogen	Region 9
Prima Deshecha Creek

LOE ID:

7743

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical monitoring (conventional pollutants only)

Data Used to Assess Water Quality:

Four of five flow-weighted event mean concentrations exceeded the water quality objective according to results in the Orange County Stormwater Annual Progress Report from 2002 through 2006. Samples were collected from December 2002 through March 2006.

Data Reference:

Orange County Stormwater Program. 2004-2007. Unified Annual Progress Reports, Program Effectiveness Assessment (San Diego Region)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water bodies shall not contain biostimulatory substances in concentrations that promote aquatic growth to the extent that such growths cause nuisance or adversely affect beneficial uses (RWQCB, 2007).
The Water Quality Control Plan for the San Diego Basin (9) states: ¿A desired goal in order to prevent plant nuisance in streams and other flowing waters appears to be 0.1 mg/L total P. These values are not to be exceeded more than 10% of the time unless studies of the specific water body in question clearly show that water quality objective changes are permissible and changes are approved by the Regional Board. Analogous threshold values have not been set for nitrogen compounds; however, natural ratios of nitrogen to phosphorus are to be determined by surveillance and monitoring and upheld. If data are lacking, a ratio of N:P = 10:1, on a weight to weight basis shall be used.¿ Since the goal for total phosphorus is 0.1 mg/L, then according to the ratio provided, the goal for total nitrogen is 1 mg/L.

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

Guideline Reference:

Water Quality Control Plan for the San Diego Basin

Spatial Representation:

Samples were collected at the mass loading station in Prima Deschecha Creek at 33.44679°, 117.64448°.

Temporal Representation:

Samples were collected from December 2002 through March 2006.

Environmental Conditions:

Samples were collected during wet weather.

QAPP Information:

QA/QC conducted according to Federal Regulations under requirements of a NPDES permit.

QAPP Information Reference(s):


DECISION ID	82410	Region 9
Prima Deshecha 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)(2016)
Revision Status	Original
Sources:	A Source Unknown
Expected TMDL Completion Date:	2027
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line(s) of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Four of the six samples exceed the objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for placing this water segment-pollutant combination on the CWA 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. Four of six samples exceeded the criterion and this exceeds the allowable frequency under table 3.1 of the Listing Policy. 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 not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the following changes to the decision: The water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.

Line of Evidence (LOE) for Decision ID 82410, Selenium	Region 9
Prima Deshecha Creek

LOE ID:

75499

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Four of six samples exceeded the criterion.

Data Reference:

Data for Various Waterbodies in Region 8 and Region 9, 2006-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the San Diego Basin

Evaluation Guideline:

California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The CTR for selenium is 5.0 ug/L.

Guideline Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Spatial Representation:

Samples were collected from Prima Deshecha Channel at Calle Grande Vista from stations PD-CGV and PDCM01.

Temporal Representation:

The sample was collected from PD-CGV on 4/17/2007. Samples were collected from PDCM01 intermittently from November 2007 through February 2009.

Environmental Conditions:

The sample collected from PD-CGV is representative of dry weather conditions. The remaining 96% of the samples collected from PDCM01 were collected after storm events.

QAPP Information:

Samples were collected and analyzed in accordance with the signed and certified, Quality Assurance Management Plan for the Orange County Stormwater Program.

QAPP Information Reference(s):