Final California 2026 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 1 - North Coast Region

Water Body Name: Mad River HU, Norton Creek
Water Body ID: CAR1091002019990617100545
Water Body Type: River & Stream
 
DECISION ID
163850
Region 1     
Mad River HU, Norton Creek
 
Pollutant: Indicator Bacteria
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2018)
Revision Status Revised
Sources: A Source Unknown
TMDL Priority: Medium
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the “ISWEBE Plan”) was adopted on August 7, 2018, and contains bacteria water quality objectives applicable to the REC-1 beneficial use. This has resulted in a change from assessing fecal coliform to assessing E. coli in fresh water and Enterococcus in saline water. Fecal coliform and freshwater enterococcus lines of evidence used in previous REC-1 beneficial use indicator bacteria decisions in the North Coast Region are not included in the 2026 Integrated Report assessment. The pollutant will again be considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy.

In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Lacking constant inputs, indicator bacteria do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of E. coli in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Historic lines of evidence for data collected prior to October 21, 2012 (i.e., data collected more than 10 years from the 2026 data solicitation cutoff date) were evaluated pursuant to these considerations and, when more recent data were available, the pre-October 21, 2012, data were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy. There was insufficient information to make a beneficial use support designation, so data collected prior to October 21, 2012, were used in the assessment.

This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One of evidence is available in the administrative record to assess this pollutant, one of which contains data collected on or after October 21, 2012. No geometric means are available to assess this waterbody.

*NORTON CREEK has three LOEs (31865, 321902, 357930) and 9 of 17 samples exceed the E. coli STV objective for the REC-1 beneficial use.
*WIDOW WHITE CREEK has one LOE (357931) and 3 of 4 samples exceed the E. coli STV objective for the REC-1 beneficial use.

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 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. NORTON CREEK has 9 of 17 samples exceed the E. coli STV objective for the REC-1 beneficial use, and this is sufficient to place Norton Creek on the 303(d) list for impaired waterbodies. WIDOW WHITE CREEK has 3 of 4 samples exceed the E. coli STV objective for the REC-1 beneficial use, and this is insufficient information to make a 303(d)-listing determination
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

This listing applies to Norton Creek.
 
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 Boa
 
DECISION ID
163850
Region 1     
Mad River HU, Norton Creek
 
Pollutant: Indicator Bacteria
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2018)
Revision Status Revised
Sources: A Source Unknown
TMDL Priority: Medium
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the “ISWEBE Plan”) was adopted on August 7, 2018, and contains bacteria water quality objectives applicable to the REC-1 beneficial use. This has resulted in a change from assessing fecal coliform to assessing E. coli in fresh water and Enterococcus in saline water. Fecal coliform and freshwater enterococcus lines of evidence used in previous REC-1 beneficial use indicator bacteria decisions in the North Coast Region are not included in the 2026 Integrated Report assessment. The pollutant will again be considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy.

In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Lacking constant inputs, indicator bacteria do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of E. coli in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Historic lines of evidence for data collected prior to October 21, 2012 (i.e., data collected more than 10 years from the 2026 data solicitation cutoff date) were evaluated pursuant to these considerations and, when more recent data were available, the pre-October 21, 2012, data were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy. There was insufficient information to make a beneficial use support designation, so data collected prior to October 21, 2012, were used in the assessment.

This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

One of evidence is available in the administrative record to assess this pollutant, one of which contains data collected on or after October 21, 2012. No geometric means are available to assess this waterbody.

*NORTON CREEK has three LOEs (31865, 321902, 357930) and 9 of 17 samples exceed the E. coli STV objective for the REC-1 beneficial use.
*WIDOW WHITE CREEK has one LOE (357931) and 3 of 4 samples exceed the E. coli STV objective for the REC-1 beneficial use.

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 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. NORTON CREEK has 9 of 17 samples exceed the E. coli STV objective for the REC-1 beneficial use, and this is sufficient to place Norton Creek on the 303(d) list for impaired waterbodies. WIDOW WHITE CREEK has 3 of 4 samples exceed the E. coli STV objective for the REC-1 beneficial use, and this is insufficient information to make a 303(d)-listing determination
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

This listing applies to Norton Creek.
 
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.
 
Listing Extent: This listing applies to Norton Creek.
 
 
Line of Evidence (LOE) for Decision ID 163850, Indicator Bacteria
Region 1     
After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
Listing Extent: This listing applies to Norton Creek.
 
 
Line of Evidence (LOE) for Decision ID 163850, Indicator Bacteria
Region 1     
Mad River HU, Norton Creek
 
LOE ID: 321902
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 11
Number of Exceedances: 4
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Coastal Pathogen TMDL data for Mad River HU, Norton Creek to determine beneficial use support and the results are as follows: 4 of the 11 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: WQ from the RWQCB1 TMDL for the 2026 Integrated Report in Region 1
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 109NR1488 (Norton Creek at Hwy 101).
Temporal Representation: The samples were collected between the days of 2016-02-17 and 2018-01-09 .
Environmental Conditions:
QAPP Information: QAPP for RWQCB1_RussianRiver
QAPP Information Reference(s): North Coast Regional Water Quality Control Board - QA Doc (2015) - RWQCB1 Russian River TMDL - 402682
QAPP Information Reference(s): North Coast Regional Water Quality Control Board - QA Doc (2015) - RWQCB1 Russian River TMDL - 402683
 
Line of Evidence (LOE) for Decision ID 163850, Indicator Bacteria
Region 1     
Mad River HU, Norton Creek
 
LOE ID: 31865
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: Mad River HU, Norton Creek
 
LOE ID: 321902
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 11
Number of Exceedances: 4
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Coastal Pathogen TMDL data for Mad River HU, Norton Creek to determine beneficial use support and the results are as follows: 4 of the 11 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: WQ from the RWQCB1 TMDL for the 2026 Integrated Report in Region 1
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 109NR1488 (Norton Creek at Hwy 101).
Temporal Representation: The samples were collected between the days of 2016-02-17 and 2018-01-09 .
Environmental Conditions:
QAPP Information: QAPP for RWQCB1_RussianRiver
QAPP Information Reference(s): North Coast Regional Water Quality Control Board - QA Doc (2015) - RWQCB1 Russian River TMDL - 402682
QAPP Information Reference(s): North Coast Regional Water Quality Control Board - QA Doc (2015) - RWQCB1 Russian River TMDL - 402683
 
Line of Evidence (LOE) for Decision ID 163850, Indicator Bacteria
Region 1     
Mad River HU, Norton Creek
 
LOE ID: 31865
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 2
Number of Exceedances: 1
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: One of the two samples exceeded the E. coli evaluation guideline.
Data Reference: Data for bacteria in various North Coast Region water bodies
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan, North Coast Region (NCRWQCB 2011): The bacteriological quality of waters of the North Coast Region shall not be degraded beyond natural background levels.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) for the North Coast Region
 
Evaluation Guideline: Draft Guidance for Fresh Water Beaches (CDPH 2011): Beach posting is recommended when single sample E. coli levels exceed 235 MPN / 100 ml.
Guideline Reference: Draft Guidance for Fresh Water Beaches. Last Update: May 8, 2006. Initial Draft: November 1997. California Department of Public Health.
 
Spatial Representation: The samples were collected from Norton Creek, tributary to Widow White Creek.
Temporal Representation: The samples were collected in September and October 2009.
Environmental Conditions:
QAPP Information: The samples were collected under the Redwood Community Action Agency's Humboldt Bay First Flush Quality Assurance Project Plan.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 163850, Indicator Bacteria
Region 1     
Mad River HU, Norton Creek
 
LOE ID: 357931
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 4
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Three of 4 samples exceeded the E. coli objective.
Data Reference: Data for bacteria in various North Coast Region water bodies
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at Widow White Creek at Murray Rd, station M005.
Temporal Representation: Samples were collected from 9/15/2008 to 10/14/2009.
Environmental Conditions:
QAPP Information: The samples were collected under the Redwood Community Action Agency's Humboldt Bay First Flush Quality Assurance Project Plan.
QAPP Information Reference(s): The State Board QA officer has determined this data to be of sufficient quality to be used in the integrated report without a QAPP. Data for future cycles will follow an approved QAPP.
 
Line of Evidence (LOE) for Decision ID 163850, Indicator Bacteria
Region 1     
Mad River HU, Norton Creek
 
LOE ID: 357930
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 4
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Four of 4 samples exceeded the E. coli objective.
Data Reference: Data for bacteria in various North Coast Region water bodies
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at Norton Creek @ Central, station M003.
Temporal Representation: Samples were collected from 9/15/2008 to 10/14/2009.
Environmental Conditions:
QAPP Information: The samples were collected under the Redwood Community Action Agency's Humboldt Bay First Flush Quality Assurance Project Plan.
QAPP Information Reference(s): The State Board QA officer has determined this data to be of sufficient quality to be used in the integrated report without a QAPP. Data for future cycles will follow an approved QAPP.
 
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Number of Exceedances: 1
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: One of the two samples exceeded the E. coli evaluation guideline.
Data Reference: Data for bacteria in various North Coast Region water bodies
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan, North Coast Region (NCRWQCB 2011): The bacteriological quality of waters of the North Coast Region shall not be degraded beyond natural background levels.
Objective/Criterion Reference: Water Quality Control Plan (Basin Plan) for the North Coast Region
 
Evaluation Guideline: Draft Guidance for Fresh Water Beaches (CDPH 2011): Beach posting is recommended when single sample E. coli levels exceed 235 MPN / 100 ml.
Guideline Reference: Draft Guidance for Fresh Water Beaches. Last Update: May 8, 2006. Initial Draft: November 1997. California Department of Public Health.
 
Spatial Representation: The samples were collected from Norton Creek, tributary to Widow White Creek.
Temporal Representation: The samples were collected in September and October 2009.
Environmental Conditions:
QAPP Information: The samples were collected under the Redwood Community Action Agency's Humboldt Bay First Flush Quality Assurance Project Plan.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 163850, Indicator Bacteria
Region 1     
Mad River HU, Norton Creek
 
LOE ID: 357931
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 4
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Three of 4 samples exceeded the E. coli objective.
Data Reference: Data for bacteria in various North Coast Region water bodies
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at Widow White Creek at Murray Rd, station M005.
Temporal Representation: Samples were collected from 9/15/2008 to 10/14/2009.
Environmental Conditions:
QAPP Information: The samples were collected under the Redwood Community Action Agency's Humboldt Bay First Flush Quality Assurance Project Plan.
QAPP Information Reference(s): The State Board QA officer has determined this data to be of sufficient quality to be used in the integrated report without a QAPP. Data for future cycles will follow an approved QAPP.
 
Line of Evidence (LOE) for Decision ID 163850, Indicator Bacteria
Region 1     
Mad River HU, Norton Creek
 
LOE ID: 357930
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 4
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Four of 4 samples exceeded the E. coli objective.
Data Reference: Data for bacteria in various North Coast Region water bodies
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at Norton Creek @ Central, station M003.
Temporal Representation: Samples were collected from 9/15/2008 to 10/14/2009.
Environmental Conditions:
QAPP Information: The samples were collected under the Redwood Community Action Agency's Humboldt Bay First Flush Quality Assurance Project Plan.
QAPP Information Reference(s): The State Board QA officer has determined this data to be of sufficient quality to be used in the integrated report without a QAPP. Data for future cycles will follow an approved QAPP.