Final California 2018 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 5 - Central Valley Region

Water Body Name: Agatha Canal (Merced County)
Water Body ID: CAR5412000020090110150509
Water Body Type: River & Stream
 
DECISION ID
77568
Region 5     
Agatha Canal (Merced County)
 
Pollutant: Selenium
Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)(2016)
Revision Status Original
Sources: A Source Unknown
TMDL Name: Grasslands Marshes Selenium TMDL
TMDL Project Code: 1209
Date TMDL Approved by USEPA: 05/01/2000
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for delisting under section 4.1 of the Listing Policy. Under section 4.1 a single line of evidence is necessary to assess listing status. Data is available from two lines of evidence for this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for removing this water segment-pollution combination from the section 303(d) list. The recommendation is based on staff findings that a total of 20 of 155 available monthly mean water sample results exceeded the water quality objective and this does not exceed the allowable frequency using Table 4.1 of the Listing Policy. According to BinomBal, listing is recommended if a sample size of 155 has 13 or more samples that exceed the evaluation criteria.

The data used satisfies the data quality requirements of section 6.1.4 of the Policy. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are being met.

Final Recommendation
This pollutant is being considered for delisting under section 4.1 of the Listing Policy. Under section 4.1, a single line of evidence is necessary to assess listing status. Data is available from two lines of evidence for this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for removing this water body-pollutant combination from the section 303(d) list. The recommendation is based on staff findings that 19 of 131 monthly means measured between October 1995 and October 2007, and 1 of 24 monthly means measured between July 2007 and June 2009 exceeded the water quality objective and this exceeds the allowable frequency using Table 4.1 of the Listing Policy. According to the binomial equation, listing is recommended if a sample size of 155 has 13 or more samples that exceed the evaluation criteria.

The data used satisfies the data quality requirements of section 6.1.4 of the Policy. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

Original listing information:
The April 19, 2010 State Water Board staff report for the 2010 Integrated Report found that an incorrect water quality objective was mistakenly used to evaluate the water quality data for selenium and make a Do Not List decision. State Water Board staff re-evaluated the available data and the line of evidence and recommendation has been revised. Based on the result of data re-evaluation, State Water Board staff recommend to List Agatha Canal for selenium.

Based on comments received on the April 19, 2010 State Water Board staff report for the 2010 Integrated Report, State Water Board staff recommended to move this this water body from the 303(d) list Category 5 to the "Being Addressed Category" for selenium because this listing is covered under the Selenium TMDL for Grasslands Marshes.

On August 4, 2010 the State Water Board approved the staff listing recommendation to place this water body on the 303(d) list (being addressed by a USEPA approved TMDL) for selenium.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should continue to be placed on the section 303(d) list because applicable water quality standards are not being exceeded. RWQCB staff also recommends that this water body-pollutant combination should continue to be placed on the 303(d)-list in the "Being Addressed Category", because this listing is covered under the Selenium TMDL for Grasslands Marshes.
 
State Board Review of Regional Board Conclusion and Recommendation: Original listing information:
The April 19, 2010 State Water Board staff report for the 2010 Integrated Report found that an incorrect water quality objective was mistakenly used to evaluate the water quality data for selenium and make a Do Not List decision. State Water Board staff re-evaluated the available data and the line of evidence and recommendation has been revised. Based on the result of data re-evaluation, State Water Board staff recommend to List Agatha Canal for selenium.

Based on comments received on the April 19, 2010 State Water Board staff report for the 2010 Integrated Report, State Water Board staff recommended to move this this water body from the 303(d) list Category 5 to the "Being Addressed Category" for selenium because this listing is covered under the Selenium TMDL for Grasslands Marshes.

On August 4, 2010 the State Water Board approved the staff listing recommendation to place this water body on the 303(d) list (being addressed by a USEPA approved TMDL) for selenium.
 
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 77568, Selenium
Region 5     
Agatha Canal (Merced County)
 
LOE ID: 59623
 
Pollutant: Selenium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 24
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: 1 of 24 monthly mean sample results exceed the criterion for Selenium.
Data Reference: RWB5S Grasslands Bypass FY0708 FY0809
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Selenium levels for Salt Slough and constructed and re-constructed water supply channels in the Grassland watershed should not exceed 2 ug/L (monthly mean) or 20 ug/L (instantaneous Maximum).
Objective/Criterion Reference: Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed
Objective/Criterion 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
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data for this line of evidence for Agatha Canal (Merced County) was collected at one monitoring site [ Agatha Canal @ Mallard Road - 541MER506]
Temporal Representation: Data was collected over the time period 7/3/2007-6/30/2009.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 77568, Selenium
Region 5     
Agatha Canal (Merced County)
 
LOE ID: 20954
 
Pollutant: Selenium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 131
Number of Exceedances: 19
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Nineteen of the 131 monthly means exceeded the evaluation objective for Selenium. There were 10 out of 526 exceedances of the instantaneous maximum.
Data Reference: San Joaquin River SWAMP Monitoring Data - Grassland Bypass
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Selenium levels for Salt Slough and constructed and re-constructed water supply channels in the Grassland watershed should not exceed 2 ug/L (monthly mean) or 20 ug/L (instantaneous Maximum).
Objective/Criterion Reference: Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at Agatha Canal @ Mallard Road.
Temporal Representation: The samples were collected from October 27, 1995 to October 25, 2007.
Environmental Conditions:
QAPP Information: Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.
QAPP Information Reference(s):
 
 
DECISION ID
75686
Region 5     
Agatha Canal (Merced County)
 
Pollutant: pH
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: 2021
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) List in a previous Integrated Report cycle. No new information was reviewed for this current Integrated Report cycle. Therefore, the previous conclusion remains unchanged, and is as follows:

One line of evidence is available in the administrative record to assess this pollutant. Seven of 28 samples exceed the water quality objective for pH.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of continuing to place this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Seven of 28 samples exceed the pH objective found in the Basin Plan 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: 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 75686, pH
Region 5     
Agatha Canal (Merced County)
 
LOE ID: 20963
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 28
Number of Exceedances: 7
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: 7 of the 28 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation objective for pH.
Data Reference: San Joaquin River SWAMP Monitoring Data - Grassland Bypass
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: pH levels should not be lower than 6.5 or higher than 8.5 (Basin Plan Objective)
Objective/Criterion Reference: Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at Agatha Canal @ Mallard Road.
Temporal Representation: The samples were collected from Oct 27 1995 to Feb 18 1997
Environmental Conditions:
QAPP Information: Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.
QAPP Information Reference(s):