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

Supporting Information

Regional Board 8 - Santa Ana Region

Water Body Name:	Mill Creek Reach 2
Water Body ID:	CAR8015800019990211110827
Water Body Type:	River & Stream


DECISION ID	69263	Region 8
Mill Creek Reach 2

Pollutant:	Indicator Bacteria
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:	Applicable WQS attained; due to change in WQS
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This 303(d) listing was originally made prior to 2006 and therefore the data is not held in the assessment database and was carried over in the 2010 and 2012 listing cycles. Additional data was provided in 2010, but resulted in a decision to retain this water segment on the 303(d) list. In 2012, the Regional Board revised its Basin Plan with new Pathogen Bacteria Indicator Objectives for REC-1 (Resolution No. R8-2012-001, approved by USEPA in 2015). In general, the primary objective is <126 E. coli organisms per 100 mL as a geomean of at least 5 samples in a running 30-day period (there were additional provisions for specific waters through UAAs, a high flow suspension provision and use of Single Sample Maximums for posting and for the case where limited data prevents the calculation of geomeans). During 2006 and 2007, a total of 56 samples were collected from Mill Creek Reach 2 at the Big Falls Campground by the Southern California Coastal Waters Research Project (SCCWRP) and were analyzed for E. coli, which resulted in the calculation of 42 30-day, 5-sample geomeans for this sampling location. Of those 42 30-day, 5-sample geomean measurements, 0 were above the current objective for Indicator Pathogen Bacteria (<126 E. coli organisms per 100 mL). Zero (0) exceedances within 42 geomean measurements falls well below the minimum number of exceedances needed to place a water segment on the 303(d) list for conventional pollutants (Table 3.2 of the Listing Policy). Therefore, Regional Board staff has made the decision to delist Mill Creek Reach 2 for ¿Pathogens¿ based on a change in objectives from ¿<200 fecal coliform organisms per 100 mL¿ to ¿<126 E. coli organisms per 100 mL¿ and the weight of evidence based on extensive, current sampling that supports this delisting decision.

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 69263, Indicator Bacteria	Region 8
Mill Creek Reach 2

LOE ID:

4423

Pollutant:

Pathogens

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 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 69263, Indicator Bacteria	Region 8
Mill Creek Reach 2

LOE ID:

21475

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

None of the samples collected exceeded EPA's Recommended single sample criteria.

Data Reference:

Orange County Coast Keeper Coastal Watersheds Project

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

USEPA Recommended Ambient Water Quality Criteria for Bacteria -1986: E. coli: log mean less than 126 organisms/100 mL based on five or more samples per 30¿day period, and single sample shall not exceed 235 organisms/100mL.

Objective/Criterion Reference:

Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at two stations: Mill Creek 1 and Mill Creek 2.
Mill Creek 1 is the most upstream of three sampling sites, and is located in the Forest Falls area, off of Torry Pines St, just above highway 38 bridge. There is a bridge just upstream of the Mill Creek area, with a concrete step down that the water flows over.
Mill Creek 2 is located downstream of Mill 1 in a pull out area with a natural wood fence, and an opening with a pass to get down to the creek.

Temporal Representation:

The samples were collected monthly starting on October 19, 2002 through June 3, 2004.

Environmental Conditions:

Staff is not aware of any special conditions that might effect interpretation of the data.

QAPP Information:

The data's quality is deemed appropriate because it was obtained under the auspices of a QAPP approved by the Regional Board.

QAPP Information Reference(s):


DECISION ID	97946	Region 8
Mill Creek Reach 2

Pollutant:	Benthic Community Effects
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:	Benthic Community Effects is being considered for placement on the CWA section 303(d) List under sections 3.9 and 3.1 of the Listing Policy. Under section 3.9, an additional line of evidence associating Benthic Community Effects with a water or sediment concentration of pollutant(s) is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this indicator. Two of the 4 benthic macroinvertebrate samples exceed (fall below) the California Streams Condition Index (CSCI) threshold for likely altered biological condition. The water segment does not have associated pollutant(s) samples that exceed water quality objectives. Based on the readily available data and information, the weight of evidence provides sufficient justification for not placing Benthic Community Effects in this water segment 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. Pursuant to section 3.9 of the Listing Policy, the water segment exhibits significant degradation in biological populations and/or communities as compared to reference site(s) using the California Stream Condition Index. 4. Pursuant to section 3.9 of the Listing Policy, the water segment does not have associated pollutant(s) samples that exceed water quality objectives. 5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not being met. The California Stream Condition Index is a new scoring tool for bioassessment data that is applicable statewide, accounts for a much wider range of natural variability, and provides equivalent scoring thresholds in all regions of the state. The CSCI has been used in some assessments this reporting cycle and will be used in the future for water quality assessment purposes statewide over the regional indices of biologic integrity (IBIs). If CSCI scores have not been calculated for data and only IBI scores are available, IBI scores will still be used to interpret the data.

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:	The California Stream Condition Index is a new scoring tool for bioassessment data that is applicable statewide, accounts for a much wider range of natural variability, and provides equivalent scoring thresholds in all regions of the state. The CSCI has been used in some assessments this reporting cycle and will be used in the future for water quality assessment purposes statewide over the regional indices of biologic integrity (IBIs). If CSCI scores have not been calculated for data and only IBI scores are available, IBI scores will still be used to interpret the data.

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 97946, Benthic Community Effects	Region 8
Mill Creek Reach 2

LOE ID:

96023

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

The sample collected had a CSCI score of 0.920858 and therefore this water body is meeting the water quality objective for the aquatic life beneficial use. This water body passed several screening criteria and was identified as a reference water body for the purposes of developing the CSCI. Reference sites where human disturbance is absent or minimal are used to set benchmark expectations for healthy streams. A large set of nearly 600 reference sites representing the broad diversity of natural stream types found across California was used to develop the CSCI.

Data Reference:

Region 8 CSCI scores and data.

Complete data set for all CSCI reference sites for the entire State.

Data for Various Pollutants in the Streams of Region 8, 2009.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Inland surface water communities and populations, including vertebrate, invertebrate, and plant species, shall not be degraded as a result of the discharge of waste. Degradation is damage to an aquatic community or population with the result that balanced community no longer exists. The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

The California Stream Condition Index (CSCI) is a biological scoring tool that helps aquatic resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score is calculated by comparing the expected condition with actual (observed) results (Rehn, A.C. et al., 2015). CSCI scores range from 0 (highly degraded) to greater than 1 (equivalent to reference). CSCI scoring of biological condition are as follows (per the scientific paper supporting the development of the CSCI scoring tool): greater than or equal to 0.92 = likely intact condition, 0.91 to 0.80 = possibly altered condition, 0.79 to 0.63 = likely altered condition, less than or equal to 0.62 = very likely altered condition. Sites with scores below 0.79 are considered to have exceeded the water quality objective for the aquatic life beneficial use.

Guideline Reference:

A Quantitative Tool for Assessing the Integrity of Southern Coastal California Streams. Environmental Management. Volume 35, number 1 (2005): pp. 1-13

Guideline Reference:

Bioassessment in complex environments: designing an index for consistent meaning in different settings

Spatial Representation:

The sample was collected at station SA-C-06-035.

Temporal Representation:

The sample was collected on 6/22/2006.

Environmental Conditions:

QAPP Information:

Samples were collected for the RWB8's Probabilistic Stream Survey CY2007 following SWAMP protocols. Data is from Region 8 CSULB database and formatted in SWAMP format.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 97946, Benthic Community Effects	Region 8
Mill Creek Reach 2

LOE ID:

81793

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Four samples were collected from three different sites on Mill Creek, Reach 2 during 2006 and 2007. One sample and one replicate were collected from station 801MIC370
(SMCR8_370). The CSCI scores for the site were 0.83 and 0.89 and to meet the temporal independence in Section 6.1.5.6 of the Listing Policy, the scores were averaged. The average CSCI score for this site is 0.86. This site is above the 0.79 threshold and therefore meets the water quality objective for the aquatic life beneficial use. The CSCI scores for the other two sites are 0.71 and 0.78. These sites are below the 0.79 threshold and therefore exceed the water quality objective for the aquatic life beneficial use.

Data Reference:

Data for Various Pollutants in the Streams of Region 8, 2009.

Region 8 CSCI scores and data.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Bioassessment in complex environments: designing an index for consistent meaning in different settings

Spatial Representation:

The samples were collected from Mill Creek stations 801MIC007 (SMCR8_007), 801MIC034 (SMCR8_034), 801MIC370 (SMCR8_370).

Temporal Representation:

The samples were collected in June 2006 at station 801MIC034 (SMCR8_034), 801MIC370(SMCR8_370) and in June 2007 at station 801MIC370 (SMCR8_370).

Environmental Conditions:

QAPP Information:

Samples were collected for the RWB8's Probabilistic Stream Survey CY2006 and CY2007 following SWAMP protocols. Data is from Region 8 CSULB database and formatted in SWAMP format. Taxonomic data is good.

QAPP Information Reference(s):


DECISION ID	96304	Region 8
Mill Creek Reach 2

Pollutant:	Nitrogen, Nitrate
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 (1) line of evidence is available in the administrative record to assess this pollutant. Zero (0) of the one (1) sample exceeds the beneficial use 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. 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 (0) of the one (1) sample exceeds the beneficial use 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 sample are 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 96304, Nitrogen, Nitrate	Region 8
Mill Creek Reach 2

LOE ID:

81794

Pollutant:

Nitrogen, Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

0 of the 1 samples do not exceed the water quality objective for Nitrate (as N) at 10 mg/L.

Data Reference:

Data for Various Pollutants in the Streams of Region 8, 2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Santa Ana Region (1995): Waters designated for MUN shall not contain concentrations of chemical constituents in excess of the MCL specified in Title 22 of the California Code of Regulations. The Nitrate (as N) MCL is 10 mg/L.

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Sample was collected at 'SMCR8_333, Mill Creek Reach 2.

Temporal Representation:

Sample was collected on 6/17/2009.

Environmental Conditions:

QAPP Information:

No quality assurance information was provided.

QAPP Information Reference(s):


DECISION ID	96363	Region 8
Mill Creek Reach 2

Pollutant:	Nitrogen, Nitrite
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 (1) line of evidence is available in the administrative record to assess this pollutant. Zero (0) of the one (1) sample exceeds the beneficial use 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. 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 (0) of the one (1) sample exceeds the beneficial use 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 sample are 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 96363, Nitrogen, Nitrite	Region 8
Mill Creek Reach 2

LOE ID:

81795

Pollutant:

Nitrogen, Nitrite

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

0 of the 1 samples do not exceed the water quality objective for Nitrite (as N) at 1 mg/L. The datum is reported as underneath the quantitation limit. This quantitation limit is less than or equal to the water quality standard, the value will be considered as meeting the water quality standard, objective, criterion, or evaluation guideline.

Data Reference:

Data for Various Pollutants in the Streams of Region 8, 2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Sample was collected at 'SMCR8_333, Mill Creek Reach 2.

Temporal Representation:

Sample was collected on 6/17/2009.

Environmental Conditions:

QAPP Information:

No quality assurance information was provided.

QAPP Information Reference(s):


DECISION ID	95548	Region 8
Mill Creek Reach 2

Pollutant:	Total Nitrogen as N
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. A single line of evidence is available in the administrative record to assess this pollutant. Zero (0) of the one (1) sample exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the 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 (0) of the one (1) sample exceeds the water quality 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 95548, Total Nitrogen as N	Region 8
Mill Creek Reach 2

LOE ID:

81796

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

The sample did not exceed the Total Nitrogen water quality objective at 1 mg/L. The datum is reported as a non-detect. This non-detect is less than or equal to the water quality standard, the value will be considered as meeting the water quality standard, objective, criterion, or evaluation guideline.

Data Reference:

Data for Various Pollutants in the Streams of Region 8, 2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Table 4-1 of the Santa Ana Basin Plan (1995) states that the water quality objective for Total Nitrogen for Mill Creek (Reach 2), is 1 mg/L.

Objective/Criterion Reference:

Water Quality Control Plan, Santa Ana River Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Sample was collected at 'SMCR8_333, Mill Creek (Reach 2).

Temporal Representation:

Sample was collected on 6/17/2009.

Environmental Conditions:

QAPP Information:

No quality assurance information was provided.

QAPP Information Reference(s):