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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name: Blackwood Creek
Water Body ID: CAR6342002119990128133830
Water Body Type: River & Stream
 
DECISION ID
168948
Region 6     
Blackwood Creek
 
Pollutant: Nitrogen
Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (being addressed by USEPA approved TMDL)(2018)
Revision Status Revised
Sources: A Source Unknown
TMDL Name: Lake Tahoe Nutrients/Sediment
TMDL Project Code: 198
Date TMDL Approved by USEPA: 08/16/2011
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal on the CWA section 303(d) List under sections 2.2 and 4.1 of the Listing Policy. Under 4.1 of the Policy, a minimum of one line of evidence is needed to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Zero of 1 samples exceeds the 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 CWA section 303(d) List. There is sufficient justification to place it in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.

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. 0 of 1 samples exceeded the objective and this is not enough samples to delist under section 4.1 of the listing policy.
4. The Lake Tahoe TMDL was approved by USEPA on 08/16/2011.
5. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
6. Blackwood Creek is a tributary to Lake Tahoe. On-the-ground efforts required by the Lake Tahoe TMDL will also achieve pollutant load reductions in waters tributary to Lake Tahoe, including Blackwood Creek. There is also a water-body specific Blackwood Creek TMDL that addresses historic channel disturbance and bedded sediment instabilities.

The largest source of nitrogen in the Lake Tahoe (and Blackwood Creek) watershed is transportation-related emissions that lead to atmospheric nitrogen deposition. The Lake Tahoe TMDL includes implementation measures to reduce atmospheric nitrogen sources. The TMDL relies on the Tahoe Regional Planning Agency to lead efforts to improve transportation infrastructure and reduce overall vehicle miles traveled in the Lake Tahoe region to reduce emissions that lead to atmospheric nutrient loading. Public transit and vehicle fleet turnover are expected to further reduce nutrient-laden emissions in the Tahoe basin that will reduce nitrogen loading in the Blackwood Creek watershed.

Furthermore, Federal, State, and larger local restoration agencies have well defined multi objective watershed restoration programs to address historic disturbances to Lake Tahoe tributary stream channels. Implementation of USFS-Lake Tahoe Basin Management Unit's Blackwood Creek Restoration Project between 2008 and 2009 helped restore the functional channel/floodplain relationship within the most degraded section of Blackwood Creek which is expected to reduce sediment and nutrient loading to Blackwood Creek. The California Tahoe Conservancy has also implemented additional work on Blackwood Creek to treat channel incision at the Highway 89 crossing that will further reduce pollutant loading. These projects are all part of the Blackwood Creek TMDL implementation plan that targets restoration to address channel instability and re-establish natural geomorphic function.

Finally, the Lake Tahoe TMDL requires the USFS-Lake Tahoe Basin Management Unit to undertake restoration actions to reduce erosion and treat urban storm water runoff from paved and unpaved roadways, campgrounds, and recreational trails within the Blackwood Creek watershed. Storm water collection, conveyance, and treatment facilities coupled with revegetation of previously disturbed lands and stabilizing areas designated for recreational use are expected to reduce nutrient loading to Blackwood Creek.

Pollutant load reductions within Blackwood Creek will be tracked through implementation of detailed performance and compliance measures and assessment and reporting protocols included in the Lake Tahoe TMDL. The TMDL Management System project is establishing activity-based tracking and reporting requirements to assess activities that are expected to reduce pollutant loading from non-urban sources.

The Lahontan Water Board and the Nevada Division of Environmental Protection will implement a Lake Tahoe TMDL Management System for managing, tracking, integrating and evaluating new information generated from TMDL implementation actions, effectiveness monitoring, research efforts, and other factors such as climate change and wildfires.

The Management System is based on an adaptive management framework to (1) link load reduction effectiveness with project implementation monitoring to improve project design and to assess if actual environmental improvement is occurring as expected; (2) establish guidance and operation protocols for how new information will be incorporated into project designs and TMDL program implementation; (3) establish prioritized TMDL research needs to fill data gaps and reduce uncertainties, and (4) implement a process for updating and reporting pollutant load reduction estimates and tracking projects within the TMDL implementation timeline.

The Lake Tahoe TMDL requires implementation, effectiveness, and status and trends monitoring. Tributary stream status and trends monitoring will track long-term changes in water quality conditions relative to established water quality standards or goals, and project-specific monitoring will be used to assess the efficacy of various implementation measures.
Long-term water quality trends and pollutant load reduction tracking in Blackwood Creek will be captured through the ongoing efforts of the Lake Tahoe Interagency Monitoring Program (LTIMP) whose primary objective is to monitor discharge, nutrient load, and sediment loads from representative streams that flow into Lake Tahoe. Nitrogen and phosphorus loading calculations are performed using the LTIMP flow and nutrient concentration database. LTIMP has monitored Blackwood Creek and other tributaries to Lake Tahoe since 1988; this data is stored on the USGS website at http://wdr.water.usgs.gov/.
 
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 insufficient information is available to determine if applicable water quality standards for the pollutant are being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation: Furthermore, Federal, State, and larger local restoration agencies have well defined multi objective watershed restoration programs to address historic disturbances to Lake Tahoe tributary stream channels. Implementation of USFS-Lake Tahoe Basin Management Unit's Blackwood Creek Restoration Project between 2008 and 2009 helped restore the functional channel/floodplain relationship within the most degraded section of Blackwood Creek which is expected to reduce sediment and nutrient loading to Blackwood Creek. The California Tahoe Conservancy has also implemented additional work on Blackwood Creek to treat channel incision at the Highway 89 crossing that will further reduce pollutant loading. These projects are all part of the Blackwood Creek TMDL implementation plan that targets restoration to address channel instability and re-establish natural geomorphic function.

Finally, the Lake Tahoe TMDL requires the USFS-Lake Tahoe Basin Management Unit to undertake restoration actions to reduce erosion and treat urban storm water runoff from paved and unpaved roadways, campgrounds, and recreational trails within the Blackwood Creek watershed. Storm water collection, conveyance, and treatment facilities coupled with revegetation of previously disturbed lands and stabilizing areas designated for recreational use are expected to reduce nutrient loading to Blackwood Creek.

Pollutant load reductions within Blackwood Creek will be tracked through implementation of detailed performance and compliance measures and assessment and reporting protocols included in the Lake Tahoe TMDL. The TMDL Management System project is establishing activity-based tracking and reporting requirements to assess activities that are expected to reduce pollutant loading from non-urban sources.

The Lahontan Water Board and the Nevada Division of Environmental Protection will implement a Lake Tahoe TMDL Management System for managing, tracking, integrating and evaluating new information generated from TMDL implementation actions, effectiveness monitoring, research efforts, and other factors such as climate change and wildfires.

The Management System is based on an adaptive management framework to (1) link load reduction effectiveness with project implementation monitoring to improve project design and to assess if actual environmental improvement is occurring as expected; (2) establish guidance and operation protocols for how new information will be incorporated into project designs and TMDL program implementation; (3) establish prioritized TMDL research needs to fill data gaps and reduce uncertainties, and (4) implement a process for updating and reporting pollutant load reduction estimates and tracking projects within the TMDL implementation timeline.

The Lake Tahoe TMDL requires implementation, effectiveness, and status and trends monitoring. Tributary stream status and trends monitoring will track long-term changes in water quality conditions relative to established water quality standards or goals, and project-specific monitoring will be used to assess the efficacy of various implementation measures.
Long-term water quality trends and pollutant load reduction tracking in Blackwood Creek will be captured through the ongoing efforts of the Lake Tahoe Interagency Monitoring Program (LTIMP) whose primary objective is to monitor discharge, nutrient load, and sediment loads from representative streams that flow into Lake Tahoe. Nitrogen and phosphorus loading calculations are performed using the LTIMP flow and nutrient concentration database. LTIMP has monitored Blackwood Creek and other tributaries to Lake Tahoe since 1988; this data is stored on the USGS website at http://wdr.water.usgs.gov/.
 
State Board Decision Recommendation:
 
 
Line of Evidence (LOE) for Decision ID 168948, Nitrogen
Region 6     
Blackwood Creek
 
LOE ID: 4587
 
Pollutant: Nitrogen
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
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 168948, Nitrogen
Region 6     
Blackwood Creek
 
LOE ID: 343141
 
Pollutant: Total Nitrogen as N
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
0 of 1 samples exceeded the water quality threshold for Nitrogen, Total
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Basin Plan objective for Nitrogen, Total in this water body is 0.19 (mg/L), (as a Mean).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: Blackwood Creek above Barker Pass Bridge (634BLW002)
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
 
DECISION ID
163660
Region 6     
Blackwood Creek
 
Pollutant: Phosphorus
Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (being addressed by USEPA approved TMDL)(2018)
Revision Status Revised
Sources: A Source Unknown
TMDL Name: Lake Tahoe Nutrients/Sediment
TMDL Project Code: 198
Date TMDL Approved by USEPA: 08/16/2011
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal on the CWA section 303(d) List under sections 2.2 and 4.1 of the Listing Policy. Under 4.1 of the Policy, a minimum of one line of evidence is needed to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. 14 of 19 samples exceed the 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 CWA section 303(d) List. There is sufficient justification to place it in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.

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 19 samples exceeded the objective and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy.
4. The Lake Tahoe TMDL was approved by USEPA on 08/16/2011.
5. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Blackwood Creek is a tributary to Lake Tahoe. On-the-ground efforts required by the Lake Tahoe TMDL will also achieve pollutant load reductions in waters tributary to Lake Tahoe, including Blackwood Creek. There is also a water-body specific Blackwood Creek TMDL that addresses historic channel disturbance and bedded sediment instabilities.

The primary source of phosphorus in Blackwood Creek is associated with historic watershed disturbance actions that have caused elevated watershed erosion rates and altered natural geomorphic processes in the stream itself. Recreational uses, including informal camping, paved and unpaved access roads, and user-created trails are all additional sources of sediment and associated phosphorus loading to the creek.

The Lake Tahoe TMDL requires that the USFS-Lake Tahoe Basin Management Unit undertake restoration actions to reduce erosion and treat urban storm water runoff from paved and unpaved roadways, campgrounds, and recreational trails within the Blackwood Creek watershed. Storm water collection, conveyance, and treatment facilities coupled with revegetation of previously disturbed lands and stabilizing areas designated for recreational use are expected to reduce sediment and associated phosphorus loading to Blackwood Creek.

Maintenance activities, including vegetation management work and restoration of small disturbed sites that are underway, or planned and expected, within the forested uplands of Blackwood Creek will further reduce or avoid increases in fine sediment and associated phosphorus loads).

Furthermore, Federal, State, and larger local restoration agencies have well defined multi objective watershed restoration programs to address historic disturbances to Lake Tahoe tributary stream channels. Implementation of USFS-Lake Tahoe Basin Management Unit's Blackwood Creek Restoration Project between 2008 and 2009 helped restore the functional channel/floodplain relationship within the most degraded section of Blackwood Creek which is expected to reduce sediment and nutrient loading to Blackwood Creek.

The California Tahoe Conservancy is also planning to implement additional work on Blackwood Creek to treat channel incision at the Highway 89 crossing that will further reduce pollutant loading. These projects are all part of the Blackwood Creek TMDL implementation plan that targets restoration to address channel instability and re-establish natural geomorphic function.

Finally, the Lake Tahoe TMDL requires implementation dust control measures which help reduce pollutant loads of fine sediment. Implementation of these measures helps address the phosphorus loading (associated with these fine sediments from dust sources) that impairs Blackwood 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: Blackwood Creek is a tributary to Lake Tahoe. On-the-ground efforts required by the Lake Tahoe TMDL will also achieve pollutant load reductions in waters tributary to Lake Tahoe, including Blackwood Creek. There is also a water-body specific Blackwood Creek TMDL that addresses historic channel disturbance and bedded sediment instabilities.

The primary source of phosphorus in Blackwood Creek is associated with historic watershed disturbance actions that have caused elevated watershed erosion rates and altered natural geomorphic processes in the stream itself. Recreational uses, including informal camping, paved and unpaved access roads, and user-created trails are all additional sources of sediment and associated phosphorus loading to the creek.

The Lake Tahoe TMDL requires that the USFS-Lake Tahoe Basin Management Unit undertake restoration actions to reduce erosion and treat urban storm water runoff from paved and unpaved roadways, campgrounds, and recreational trails within the Blackwood Creek watershed. Storm water collection, conveyance, and treatment facilities coupled with revegetation of previously disturbed lands and stabilizing areas designated for recreational use are expected to reduce sediment and associated phosphorus loading to Blackwood Creek.

Maintenance activities, including vegetation management work and restoration of small disturbed sites that are underway, or planned and expected, within the forested uplands of Blackwood Creek will further reduce or avoid increases in fine sediment and associated phosphorus loads).

Furthermore, Federal, State, and larger local restoration agencies have well defined multi objective watershed restoration programs to address historic disturbances to Lake Tahoe tributary stream channels. Implementation of USFS-Lake Tahoe Basin Management Unit's Blackwood Creek Restoration Project between 2008 and 2009 helped restore the functional channel/floodplain relationship within the most degraded section of Blackwood Creek which is expected to reduce sediment and nutrient loading to Blackwood Creek.

The California Tahoe Conservancy is also planning to implement additional work on Blackwood Creek to treat channel incision at the Highway 89 crossing that will further reduce pollutant loading. These projects are all part of the Blackwood Creek TMDL implementation plan that targets restoration to address channel instability and re-establish natural geomorphic function.

Finally, the Lake Tahoe TMDL requires implementation dust control measures which help reduce pollutant loads of fine sediment. Implementation of these measures helps address the phosphorus loading (associated with these fine sediments from dust sources) that impairs Blackwood Creek.
 
State Board Decision Recommendation:
 
 
Line of Evidence (LOE) for Decision ID 163660, Phosphorus
Region 6     
Blackwood Creek
 
LOE ID: 343243
 
Pollutant: Phosphorus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
1 of 1 samples exceeded the water quality threshold for Phosphorus as P
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Basin Plan objective for Phosphorus as P in this water body is 0.015 (mg/L), (as a Mean).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: Blackwood Creek above Barker Pass Bridge (634BLW002)
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 163660, Phosphorus
Region 6     
Blackwood Creek
 
LOE ID: 343662
 
Pollutant: Phosphorus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 13
Number of Exceedances: 11
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed USGS California Water Science Center data to determine beneficial use support and results are as follows:
11 of 13 samples exceeded the water quality threshold for Phosphorus as P
Data Reference: WQX from the NWQMP for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Basin Plan objective for Phosphorus as P in this water body is 0.015 (mg/L), (as a Mean).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: BLACKWOOD C NR TAHOE CITY CA (USGS-10336660)
Temporal Representation: The samples were collected between the dates of 2010-09-13 and 2022-09-08
Environmental Conditions:
QAPP Information: NA
QAPP Information Reference(s): QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
 
Line of Evidence (LOE) for Decision ID 163660, Phosphorus
Region 6     
Blackwood Creek
 
LOE ID: 343664
 
Pollutant: Phosphorus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed USGS California Water Science Center data to determine beneficial use support and results are as follows:
2 of 5 samples exceeded the water quality threshold for Phosphorus as P
Data Reference: WQX from the NWQMP for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Basin Plan objective for Phosphorus as P in this water body is 0.015 (mg/L), (as a Mean).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: BLACKWOOD C NR TAHOE CITY CA (USGS-10336660)
Temporal Representation: The samples were collected between the dates of 2010-09-13 and 2014-08-04
Environmental Conditions:
QAPP Information: NA
QAPP Information Reference(s): QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
 
 
DECISION ID
162083
Region 6     
Blackwood Creek
 
Pollutant: Alkalinity as CaCO3
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)(2018)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
 
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 the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
 
Line of Evidence (LOE) for Decision ID 162083, Alkalinity as CaCO3
Region 6     
Blackwood Creek
 
LOE ID: 98463
 
Pollutant: Alkalinity as CaCO3
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Alkalinity as CaCO3.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Tahoe Regional Planning Agency (TRPA) Tahoe Ambient Monitoring program.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The National Recommended Water Quality Criteria for Alkalinity as CaCO3 for the protection of freshwater aquatic life is not less than 20000 ug/L. (National Recommended Water Quality Criteria 2016)
Objective/Criterion Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Current as of 08/03/2016.
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (634S14243, 634S14251)
Temporal Representation: The samples were collected between the dates of 2014-08-13 and 2014-08-14
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
 
Line of Evidence (LOE) for Decision ID 162083, Alkalinity as CaCO3
Region 6     
Blackwood Creek
 
LOE ID: 337827
 
Pollutant: Alkalinity as CaCO3
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Alkalinity as CaCO3.
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
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 (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).
Guideline Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Current as of 08/03/2016.
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S14251 (Blackwood Creek 634S14251 Status 2014).
Temporal Representation: The samples were collected between the dates of 2018-06-28 and 2018-06-28
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162083, Alkalinity as CaCO3
Region 6     
Blackwood Creek
 
LOE ID: 337923
 
Pollutant: Alkalinity as CaCO3
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality threshold for Alkalinity as CaCO3.
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
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 (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).
Guideline Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Current as of 08/03/2016.
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S17323 (634S17323 Blackwood Creek Status 2017).
Temporal Representation: The samples were collected between the dates of 2017-07-18 and 2017-07-18
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162083, Alkalinity as CaCO3
Region 6     
Blackwood Creek
 
LOE ID: 337869
 
Pollutant: Alkalinity as CaCO3
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Alkalinity as CaCO3.
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: 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 (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).
Guideline Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Current as of 08/03/2016.
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
 
DECISION ID
168672
Region 6     
Blackwood Creek
 
Pollutant: Ammonia
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
 
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 the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
 
Line of Evidence (LOE) for Decision ID 168672, Ammonia
Region 6     
Blackwood Creek
 
LOE ID: 338181
 
Pollutant: Ammonia (Unionized)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Ammonia as N, Unionized.
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The un-ionized ammonia water quality objective to protect aquatic life in freshwater is temperature and pH dependent and is calculated according to the equation for the four-day criterion defined in Chapter 3 of The Water Quality Control Plan for the Lahontan Region.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 168672, Ammonia
Region 6     
Blackwood Creek
 
LOE ID: 338098
 
Pollutant: Nitrogen, ammonia (Total Ammonia)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Ammonia as N.
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The total ammonia water quality objective to protect aquatic life in freshwater is temperature and pH dependent and is calculated according to the equation for the four-day criterion defined in Chapter 3 of The Water Quality Control Plan for the Lahontan Region.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
 
DECISION ID
162077
Region 6     
Blackwood Creek
 
Pollutant: Boron
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.
 
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:
 
 
Line of Evidence (LOE) for Decision ID 162077, Boron
Region 6     
Blackwood Creek
 
LOE ID: 338350
 
Pollutant: Boron
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Boron.
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Waters designated as MUN shall not contain concentrations of chemical constituents in amounts that adversely affect the water for beneficial uses (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: Drinking water notification levels are published by the Division of Drinking Water. Notification levels are for chemicals for which there is no drinking water MCL. If a notification level is exceeded, local government notification is required and customer notification is recommended. The notification level for Boron is 1 mg/L.
Guideline Reference: Drinking Water Notification and Response Levels: An Overview
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
 
DECISION ID
163659
Region 6     
Blackwood Creek
 
Pollutant: Chloride
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.
 
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:
 
 
Line of Evidence (LOE) for Decision ID 163659, Chloride
Region 6     
Blackwood Creek
 
LOE ID: 342797
 
Pollutant: Chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
0 of 1 samples exceeded the water quality threshold for Chloride
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Basin Plan objective for Chloride in this water body is 0.3 (mg/L), (as a Mean).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: Blackwood Creek above Barker Pass Bridge (634BLW002)
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
 
DECISION ID
168711
Region 6     
Blackwood Creek
 
Pollutant: Indicator Bacteria
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)(2018)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

(Fecal coliform lines of evidence used in previous indicator bacteria decisions in the Lahontan Region have been removed, starting in the 2026 Integrated Report, since the Lahontan Region's fecal coliform water quality objective was removed from the Basin Plan in 2024).
 
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 the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
 
Line of Evidence (LOE) for Decision ID 168711, Indicator Bacteria
Region 6     
Blackwood Creek
 
LOE ID: 336832
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed RWB6_BACT_Monitoring data for Blackwood Creek to determine beneficial use support and the results are as follows: 0 of the 1 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 Lahontan Regional Water Board's Nonpoint Source Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use in waters other than Lake Thaoe, 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): 634BLKB10 (Blackwood Creek abv Hwy 89).
Temporal Representation: The samples were collected between the days of 2015-06-01 and 2015-06-01 .
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 168711, Indicator Bacteria
Region 6     
Blackwood Creek
 
LOE ID: 99801
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed RWB6_BACT_Monitoring data for Blackwood Creek to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the Statistical Threshold Value (STV) water quality standard for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for Regional Water Board 6 Bacteria Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective applicable to all waters, except Lake Tahoe, where the salinity is less than 10 parts per thousand (ppth) 95 percent or more of the time is a STATISTICAL THRESHOLD VALUE (STV) of 320 cfu/100 mL not to be exceeded more than 10 percent of the time (calculated monthly).
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): 634BLKB05
Temporal Representation: The samples were collected between the days of 2014-10-03 and 2014-10-03 .
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
 
 
DECISION ID
162078
Region 6     
Blackwood 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)(2018)
Revision Status Revised
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 of evidence is necessary to assess listing status.

Eight lines of evidence are available in the administrative record to assess this parameter: 5 which assess dissolved oxygen concentration data and 3 which assess dissolved oxygen percent saturation data. Zero of 50 samples are below the objective for minimum dissolved oxygen concentration. Two of 3 samples are below the objective for minimum dissolved oxygen percent saturation.

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 50 samples are below the objective for minimum dissolved oxygen concentration. Two of 3 samples are below the objective for minimum dissolved oxygen percent saturation. This does not exceed the allowable number of exceedances 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 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:
 
 
Line of Evidence (LOE) for Decision ID 162078, Oxygen, Dissolved
Region 6     
Blackwood Creek
 
LOE ID: 339043
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: For waters with the beneficial uses of COLD, COLD with SPWN, WARM, and WARM with SPWN, the minimum dissolved oxygen concentration shall not be less than that specified in Table 3-6. (Water Quality Control Plan, Lahontan Region)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S14251 (Blackwood Creek 634S14251 Status 2014).
Temporal Representation: The samples were collected between the dates of 2018-06-28 and 2018-06-28
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162078, Oxygen, Dissolved
Region 6     
Blackwood Creek
 
LOE ID: 341610
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 46
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed USGS California Water Science Center data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 46 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference: WQX from the NWQMP for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: For waters with the beneficial uses of COLD, COLD with SPWN, WARM, and WARM with SPWN, the minimum dissolved oxygen concentration shall not be less than that specified in Table 3-6. (Water Quality Control Plan, Lahontan Region)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: USGS-10336660 (BLACKWOOD C NR TAHOE CITY CA).
Temporal Representation: The samples were collected between the dates of 2010-09-13 and 2022-09-08
Environmental Conditions:
QAPP Information: QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
QAPP Information Reference(s): QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
 
Line of Evidence (LOE) for Decision ID 162078, Oxygen, Dissolved
Region 6     
Blackwood Creek
 
LOE ID: 339479
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality threshold for Oxygen, Saturation.
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Lahontan Region's water quality objective states that the dissolved oxygen concentration shall not be less than 80 percent of saturation.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S14251 (Blackwood Creek 634S14251 Status 2014).
Temporal Representation: The samples were collected between the dates of 2018-06-28 and 2018-06-28
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162078, Oxygen, Dissolved
Region 6     
Blackwood Creek
 
LOE ID: 339033
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: For waters with the beneficial uses of COLD, COLD with SPWN, WARM, and WARM with SPWN, the minimum dissolved oxygen concentration shall not be less than that specified in Table 3-6. (Water Quality Control Plan, Lahontan Region)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S17323 (634S17323 Blackwood Creek Status 2017).
Temporal Representation: The samples were collected between the dates of 2017-07-18 and 2017-07-18
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162078, Oxygen, Dissolved
Region 6     
Blackwood Creek
 
LOE ID: 339498
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Oxygen, Saturation.
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Lahontan Region's water quality objective states that the dissolved oxygen concentration shall not be less than 80 percent of saturation.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S17323 (634S17323 Blackwood Creek Status 2017).
Temporal Representation: The samples were collected between the dates of 2017-07-18 and 2017-07-18
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162078, Oxygen, Dissolved
Region 6     
Blackwood Creek
 
LOE ID: 339459
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality threshold for Oxygen, Saturation.
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan for the Lahontan Region's water quality objective states that the dissolved oxygen concentration shall not be less than 80 percent of saturation.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162078, Oxygen, Dissolved
Region 6     
Blackwood Creek
 
LOE ID: 130021
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Oxygen, Dissolved.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Tahoe Regional Planning Agency (TRPA) Tahoe Ambient Monitoring program.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: For waters with the beneficial uses of COLD, COLD with SPWN, WARM, and WARM with SPWN, the minimum dissolved oxygen concentration shall not be less than that specified in Table 3-6. (Water Quality Control Plan, Lahontan Region)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (634S14243)
Temporal Representation: The samples were collected between the dates of 2014-08-13 and 2014-08-13
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
 
Line of Evidence (LOE) for Decision ID 162078, Oxygen, Dissolved
Region 6     
Blackwood Creek
 
LOE ID: 339074
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: For waters with the beneficial uses of COLD, COLD with SPWN, WARM, and WARM with SPWN, the minimum dissolved oxygen concentration shall not be less than that specified in Table 3-6. (Water Quality Control Plan, Lahontan Region)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
 
DECISION ID
163661
Region 6     
Blackwood Creek
 
Pollutant: Sediment
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
TMDL Name: Blackwood Creek sediment
TMDL Project Code: 182
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
 
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 the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
 
Line of Evidence (LOE) for Decision ID 163661, Sediment
Region 6     
Blackwood Creek
 
LOE ID: 343677
 
Pollutant: Sediment
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed USGS California Water Science Center data to determine beneficial use support and results are as follows:
1 of 2 samples exceeded the water quality threshold for Suspended Sediment Concentration
Data Reference: WQX from the NWQMP for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Basin Plan objective for Suspended Sediment Concentration in this water body is 60 (mg/L), (as a 90th Percentile).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: BLACKWOOD C NR TAHOE CITY CA (USGS-10336660)
Temporal Representation: The samples were collected between the dates of 2017-01-08 and 2019-11-07
Environmental Conditions:
QAPP Information: NA
QAPP Information Reference(s): QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
 
 
DECISION ID
162080
Region 6     
Blackwood Creek
 
Pollutant: Sodium
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.
 
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:
 
 
Line of Evidence (LOE) for Decision ID 162080, Sodium
Region 6     
Blackwood Creek
 
LOE ID: 340242
 
Pollutant: Sodium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Sodium.
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: 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 (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: Per the Drinking Water Standards and Health Advisories (USEPA 2012), the health advisory for sodium for individuals on a sodium-restricted diet is 20 mg/l.
Guideline Reference: 2012 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
 
DECISION ID
168635
Region 6     
Blackwood Creek
 
Pollutant: Specific Conductivity
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)(2018)
Revision Status Revised
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 of evidence is necessary to assess listing status.

Five lines of evidence are available in the administrative record to assess this pollutant. Zero of one 79 exceed the objective for specific conductivity (MCL).

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 one 79 exceed the objective for specific conductivity (MCL) and this does not exceed 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 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:
 
 
Line of Evidence (LOE) for Decision ID 168635, Specific Conductivity
Region 6     
Blackwood Creek
 
LOE ID: 97351
 
Pollutant: Specific Conductivity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for SpecificConductivity.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Tahoe Regional Planning Agency (TRPA) Tahoe Ambient Monitoring program.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Water designated as MUN shall not contain concentrations of chemical constituents in excess of the maximum contaminant level (MCL) or secondary maximum contaminant level (SMCL) based upon drinking water standards specified in Title 22 of the California Code of Regulations (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's \Chemical Constituents\" objective. The California Secondary MCL for specific conductivity is 900 uS/cm."
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (634S14243)
Temporal Representation: The samples were collected between the dates of 2014-08-13 and 2014-08-13
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
 
Line of Evidence (LOE) for Decision ID 168635, Specific Conductivity
Region 6     
Blackwood Creek
 
LOE ID: 340341
 
Pollutant: Specific Conductivity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for SpecificConductivity.
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water designated as MUN shall not contain concentrations of chemical constituents in excess of the maximum contaminant level (MCL) or secondary maximum contaminant level (SMCL) based upon drinking water standards specified in Title 22 of the California Code of Regulations (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's 'Chemical Constituents' objective. The California Secondary MCL for specific conductivity is 900 uS/cm.
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S14251 (Blackwood Creek 634S14251 Status 2014).
Temporal Representation: The samples were collected between the dates of 2018-06-28 and 2018-06-28
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 168635, Specific Conductivity
Region 6     
Blackwood Creek
 
LOE ID: 340327
 
Pollutant: Specific Conductivity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for SpecificConductivity.
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water designated as MUN shall not contain concentrations of chemical constituents in excess of the maximum contaminant level (MCL) or secondary maximum contaminant level (SMCL) based upon drinking water standards specified in Title 22 of the California Code of Regulations (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's 'Chemical Constituents' objective. The California Secondary MCL for specific conductivity is 900 uS/cm.
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S17323 (634S17323 Blackwood Creek Status 2017).
Temporal Representation: The samples were collected between the dates of 2017-07-18 and 2017-07-18
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 168635, Specific Conductivity
Region 6     
Blackwood Creek
 
LOE ID: 340556
 
Pollutant: Specific Conductivity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for SpecificConductivity.
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Water designated as MUN shall not contain concentrations of chemical constituents in excess of the maximum contaminant level (MCL) or secondary maximum contaminant level (SMCL) based upon drinking water standards specified in Title 22 of the California Code of Regulations (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's 'Chemical Constituents' objective. The California Secondary MCL for specific conductivity is 900 uS/cm.
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 168635, Specific Conductivity
Region 6     
Blackwood Creek
 
LOE ID: 341906
 
Pollutant: Specific Conductivity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 75
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed USGS California Water Science Center data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 75 samples exceeded the water quality threshold for SpecificConductivity.
Data Reference: WQX from the NWQMP for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water designated as MUN shall not contain concentrations of chemical constituents in excess of the maximum contaminant level (MCL) or secondary maximum contaminant level (SMCL) based upon drinking water standards specified in Title 22 of the California Code of Regulations (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's 'Chemical Constituents' objective. The California Secondary MCL for specific conductivity is 900 uS/cm.
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site: USGS-10336660 (BLACKWOOD C NR TAHOE CITY CA).
Temporal Representation: The samples were collected between the dates of 2010-09-13 and 2022-09-08
Environmental Conditions:
QAPP Information: QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
QAPP Information Reference(s): QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
 
 
DECISION ID
162081
Region 6     
Blackwood Creek
 
Pollutant: Sulfates
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.
 
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:
 
 
Line of Evidence (LOE) for Decision ID 162081, Sulfates
Region 6     
Blackwood Creek
 
LOE ID: 340726
 
Pollutant: Sulfates
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Sulfate.
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Secondary MCL that is incorporated by reference in the Water Quality Control Plan, Lahontan Region for Sulfate 250 mg/L (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
 
DECISION ID
163662
Region 6     
Blackwood Creek
 
Pollutant: Total Dissolved Solids
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.
 
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:
 
 
Line of Evidence (LOE) for Decision ID 163662, Total Dissolved Solids
Region 6     
Blackwood Creek
 
LOE ID: 343403
 
Pollutant: Total Dissolved Solids
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
0 of 1 samples exceeded the water quality threshold for Total Dissolved Solids
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Basin Plan objective for Total Dissolved Solids in this water body is 70 (mg/L), (as a Mean).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: Blackwood Creek above Barker Pass Bridge (634BLW002)
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
 
DECISION ID
162079
Region 6     
Blackwood 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)(2018)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.
 
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:
 
 
Line of Evidence (LOE) for Decision ID 162079, pH
Region 6     
Blackwood Creek
 
LOE ID: 339609
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH. The objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality thresholds could not be made.
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide objective for pH states: 'In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.'
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162079, pH
Region 6     
Blackwood Creek
 
LOE ID: 339885
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH. The objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality thresholds could not be made.
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide objective for pH states: 'In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.'
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S14251 (Blackwood Creek 634S14251 Status 2014).
Temporal Representation: The samples were collected between the dates of 2018-06-28 and 2018-06-28
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162079, pH
Region 6     
Blackwood Creek
 
LOE ID: 340105
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH. The objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality thresholds could not be made.
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide objective for pH states: 'In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.'
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S17323 (634S17323 Blackwood Creek Status 2017).
Temporal Representation: The samples were collected between the dates of 2017-07-18 and 2017-07-18
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162079, pH
Region 6     
Blackwood Creek
 
LOE ID: 339680
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH. The objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality thresholds could not be made.
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide objective for pH states: 'In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.'
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S14251 (Blackwood Creek 634S14251 Status 2014).
Temporal Representation: The samples were collected between the dates of 2018-06-28 and 2018-06-28
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162079, pH
Region 6     
Blackwood Creek
 
LOE ID: 340146
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed TRPA Tahoe Ambient Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH. The objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality thresholds could not be made.
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide objective for pH states: 'In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.'
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S17323 (634S17323 Blackwood Creek Status 2017).
Temporal Representation: The samples were collected between the dates of 2017-07-18 and 2017-07-18
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162079, pH
Region 6     
Blackwood Creek
 
LOE ID: 339972
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH. The objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality thresholds could not be made.
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide objective for pH states: 'In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.'
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 162079, pH
Region 6     
Blackwood Creek
 
LOE ID: 341656
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed USGS California Water Science Center data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 9 samples exceeded the water quality threshold for pH. The objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality thresholds could not be made.
Data Reference: WQX from the NWQMP for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide objective for pH states: 'In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.'
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: USGS-10336660 (BLACKWOOD C NR TAHOE CITY CA).
Temporal Representation: The samples were collected between the dates of 2012-09-04 and 2021-09-14
Environmental Conditions:
QAPP Information: QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
QAPP Information Reference(s): QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
 
Line of Evidence (LOE) for Decision ID 162079, pH
Region 6     
Blackwood Creek
 
LOE ID: 341660
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed USGS California Water Science Center data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 9 samples exceeded the water quality threshold for pH. The objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality thresholds could not be made.
Data Reference: WQX from the NWQMP for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide objective for pH states: 'In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.'
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: USGS-10336660 (BLACKWOOD C NR TAHOE CITY CA).
Temporal Representation: The samples were collected between the dates of 2012-09-04 and 2021-09-14
Environmental Conditions:
QAPP Information: QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
QAPP Information Reference(s): QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
 
Line of Evidence (LOE) for Decision ID 162079, pH
Region 6     
Blackwood Creek
 
LOE ID: 129700
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: 0 of 0 samples exceeded the water quality standard for pH. Although pH data does exist for this waterbody, the objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality standards could not be made.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Tahoe Regional Planning Agency (TRPA) Tahoe Ambient Monitoring program.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide objective for pH states: \In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.\""
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (634S14243)
Temporal Representation: The samples were collected between the dates of 2014-08-13 and 2014-08-13
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
 
Line of Evidence (LOE) for Decision ID 162079, pH
Region 6     
Blackwood Creek
 
LOE ID: 129660
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: 0 of 0 samples exceeded the water quality standard for pH. Although pH data does exist for this waterbody, the objective for this pollutant requires background information that is currently unavailable, and therefore an assessment of water quality standards could not be made.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Tahoe Regional Planning Agency (TRPA) Tahoe Ambient Monitoring program.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide objective for pH states: \In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.\""
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (634S14243)
Temporal Representation: The samples were collected between the dates of 2014-08-13 and 2014-08-13
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
 
 
DECISION ID
171782
Region 6     
Blackwood Creek
 
Pollutant: Benthic Community Effects
Final Listing Decision: 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)(2018)
Revision Status Revised
Sources: A Source Unknown
TMDL Priority: Low
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Benthic Community Effects are being considered for placement on the CWA section 303(d) List under sections 3.9 of the Listing Policy. Under section 3.9, additional lines of evidence (LOEs) associating the Benthic Community Effects decision with a water or sediment concentration of pollutants other than benthic-macroinvertebrate bioassessment or habitat assessment LOEs are necessary to place a water body on the 303(d) List for Benthic Community Effects.
Five lines of evidence evaluating benthic-macroinvertebrate bioassessment data are available in the administrative record to assess this indicator. Three of seven benthic-macroinvertebrate samples exceed the California Stream Condition Index (CSCI) impairment threshold. Additionally, there are associated pollutant impairments on the waterbody (including but not necessarily limited to nitrogen and phosphorus). Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for placing Benthic Community Effects in this waterbody 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. 3 of 7 benthic-macroinvertebrate bioassessment samples had CSCI scores below 0.79. Therefore, this water body is exceeding the water quality threshold for the protection of the COLD beneficial use.
4. Pursuant to section 3.9 of the Listing Policy, the water segment has 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 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:
 
 
Line of Evidence (LOE) for Decision ID 171782, Benthic Community Effects
Region 6     
Blackwood Creek
 
LOE ID: 343243
 
Pollutant: Phosphorus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data to determine beneficial use support and results are as follows:
1 of 1 samples exceeded the water quality threshold for Phosphorus as P
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Basin Plan objective for Phosphorus as P in this water body is 0.015 (mg/L), (as a Mean).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: Blackwood Creek above Barker Pass Bridge (634BLW002)
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 171782, Benthic Community Effects
Region 6     
Blackwood Creek
 
LOE ID: 343662
 
Pollutant: Phosphorus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 13
Number of Exceedances: 11
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed USGS California Water Science Center data to determine beneficial use support and results are as follows:
11 of 13 samples exceeded the water quality threshold for Phosphorus as P
Data Reference: WQX from the NWQMP for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Basin Plan objective for Phosphorus as P in this water body is 0.015 (mg/L), (as a Mean).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: BLACKWOOD C NR TAHOE CITY CA (USGS-10336660)
Temporal Representation: The samples were collected between the dates of 2010-09-13 and 2022-09-08
Environmental Conditions:
QAPP Information: NA
QAPP Information Reference(s): QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
 
Line of Evidence (LOE) for Decision ID 171782, Benthic Community Effects
Region 6     
Blackwood Creek
 
LOE ID: 4587
 
Pollutant: Nitrogen
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
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 171782, Benthic Community Effects
Region 6     
Blackwood Creek
 
LOE ID: 343664
 
Pollutant: Phosphorus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed USGS California Water Science Center data to determine beneficial use support and results are as follows:
2 of 5 samples exceeded the water quality threshold for Phosphorus as P
Data Reference: WQX from the NWQMP for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Basin Plan objective for Phosphorus as P in this water body is 0.015 (mg/L), (as a Mean).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site: BLACKWOOD C NR TAHOE CITY CA (USGS-10336660)
Temporal Representation: The samples were collected between the dates of 2010-09-13 and 2014-08-04
Environmental Conditions:
QAPP Information: NA
QAPP Information Reference(s): QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
 
Line of Evidence (LOE) for Decision ID 171782, Benthic Community Effects
Region 6     
Blackwood Creek
 
LOE ID: 352829
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: Water Board staff assessed data for 634S17323 to determine beneficial use support and the results are as follows: 0 of 1 samples exceeded the water quality standard. CSCI scores were from 0.979796 to 0.979796 .
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
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. (Lahontan Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
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 (Rhen, 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: Bioassessment in complex environments: designing an index for consistent meaning in different settings
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S17323 (634S17323 Blackwood Creek Status 2017).
Temporal Representation: Samples were collected from 2017-07-18 to 2017-07-18.
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 171782, Benthic Community Effects
Region 6     
Blackwood Creek
 
LOE ID: 352773
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: Water Board staff assessed data for 634BLW002 to determine beneficial use support and the results are as follows: 1 of 1 samples exceeded the water quality standard. CSCI scores were from 0.77 to 0.77 .
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: 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. (Lahontan Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
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 (Rhen, 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: Bioassessment in complex environments: designing an index for consistent meaning in different settings
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: Samples were collected from 2017-09-26 to 2017-09-26.
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 171782, Benthic Community Effects
Region 6     
Blackwood Creek
 
LOE ID: 352796
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: Water Board staff assessed data for 634S14243 to determine beneficial use support and the results are as follows: 1 of 1 samples exceeded the water quality standard. CSCI scores were from 0.364936 to 0.364936 .
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
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. (Lahontan Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
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 (Rhen, 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: Bioassessment in complex environments: designing an index for consistent meaning in different settings
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S14243 (Blackwood Creek 634S14243 Status 2014).
Temporal Representation: Samples were collected from 2014-08-13 to 2014-08-13.
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
Line of Evidence (LOE) for Decision ID 171782, Benthic Community Effects
Region 6     
Blackwood Creek
 
LOE ID: 96466
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 1
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: There were two CSCI scores for this site. One score was from station 634S14243 and had the score 0.378662728, and there were two samples collected on one day from station 634S14251 that averaged to 0.941196053. One of these two scores exceeds the water quality objective.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the Tahoe Regional Planning Agency (TRPA) Tahoe Ambient Monitoring program.
 
SWAMP Data:
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are lethal to or that produce significant alterations in population or community ecology or receiving water biota. In addition, the health and life history characteristics of aquatic organisms in waters affected by controllable water quality factors shall not differ significantly from those for the same waters in areas unaffected by controllable water quality factors.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
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 (Rhen, 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: Bioassessment in complex environments: designing an index for consistent meaning in different settings
 
Spatial Representation: Samples collected at the following station: 634S14243
Temporal Representation: Sample was collected on 8/13/2014
Environmental Conditions:
QAPP Information: QAPP for TRPA Tahoe Ambient Monitoring
QAPP Information Reference(s): Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
 
Line of Evidence (LOE) for Decision ID 171782, Benthic Community Effects
Region 6     
Blackwood Creek
 
LOE ID: 352799
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: Water Board staff assessed data for 634S14251 to determine beneficial use support and the results are as follows: 0 of 2 samples exceeded the water quality standard. CSCI scores were from 1.02798 to 1.19197 .
Data Reference: Benthic, Field, Habitat from the Tahoe Regional Planning Authority for the 2026 Integrated Report in Region 6
 
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. (Lahontan Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
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 (Rhen, 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: Bioassessment in complex environments: designing an index for consistent meaning in different settings
 
Spatial Representation: The samples were collected at 1 monitoring site: 634S14251 (Blackwood Creek 634S14251 Status 2014).
Temporal Representation: Samples were collected from 2014-08-14 to 2018-06-28.
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
 
DECISION ID
69086
Region 6     
Blackwood Creek
 
Pollutant: Iron
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 Revised
Sources: A Source Unknown | Unknown Nonpoint Source
TMDL Priority: Low
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Regional Board Conclusion:

This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle.

No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows:

303(d) listing decisions made prior to 2006 were not held in an assessment database. The Regional Boards will update this decision when new data and information become available and are assessed.
 
Regional Board Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
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 69086, Iron
Region 6     
Blackwood Creek
 
LOE ID: 4586
 
Pollutant: Iron
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference pre-2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Unspecified
Objective/Criterion Reference: Placeholder reference pre-2006 303(d)
 
Evaluation Guideline: Unspecified
Guideline Reference: Placeholder reference pre-2006 303(d)
 
Spatial Representation: Unspecified
Temporal Representation: Unspecified
Environmental Conditions: Unspecified
QAPP Information: Unspecified
QAPP Information Reference(s):
 
 
DECISION ID
162082
Region 6     
Blackwood Creek
 
Pollutant: Turbidity
Final Listing Decision: 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)(2018)
Revision Status Revised
Sources: A Source Unknown
TMDL Priority: Low
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 of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. Sixteen of 179 samples exceed the objective (MCL).

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. Sixteen of 179 samples exceed the objective (MCL) 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:
 
 
Line of Evidence (LOE) for Decision ID 162082, Turbidity
Region 6     
Blackwood Creek
 
LOE ID: 341967
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 46
Number of Exceedances: 13
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed USGS California Water Science Center data for Blackwood Creek to determine beneficial use support and results are as follows: 13 of 46 samples exceeded the water quality threshold for Turbidity.
Data Reference: WQX from the NWQMP for the 2026 Integrated Report in Region 6
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water designated as MUN shall not contain concentrations of chemical constituents in excess of the maximum contaminant level (MCL) or secondary maximum contaminant level (SMCL) based upon drinking water standards specified in Title 22 of the California Code of Regulations. The Lahontan Basin Plan also has regionwide turbidity objective for other beneficial uses that states: Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10%.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the Lahontan Basin Plan's 'Chemical Constituents' objective. The Secondary MCL for turbidity is 5 NTU. Calculation of a numeric objective for other beneficial uses requires comparison with upstream or other background data which may not be available as part of the data used for water quality assessment.
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site: USGS-10336660 (BLACKWOOD C NR TAHOE CITY CA).
Temporal Representation: The samples were collected between the dates of 2016-10-16 and 2022-09-08
Environmental Conditions:
QAPP Information: QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
QAPP Information Reference(s): QAPP for USGS Data Collected during the 2026 Integrated Report Cycle
 
Line of Evidence (LOE) for Decision ID 162082, Turbidity
Region 6     
Blackwood Creek
 
LOE ID: 98841
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 32
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed NWIS data for Blackwood Creek to determine beneficial use support and results are as follows: 3 of 32 samples exceeded the water quality standard for Turbidity.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Water designated as MUN shall not contain concentrations of chemical constituents in excess of the maximum contaminant level (MCL) or secondary maximum contaminant level (SMCL) based upon drinking water standards specified in Title 22 of the California Code of Regulations. The Lahontan Basin Plan also has regionwide turbidity objective for other beneficial uses that states: Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10%.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the Lahontan Basin Plan's \Chemical Constituents\" objective. The Secondary MCL for turbidity is 5 NTU. Calculation of a numeric objective for other beneficial uses requires comparison with upstream or other background data which may not be available as part of the data used for water quality assessment. "
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (USGS-10336660)
Temporal Representation: The samples were collected between the dates of 2014-10-20 and 2016-09-16
Environmental Conditions:
QAPP Information: QAPP not required for federal data
QAPP Information Reference(s): This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.
 
Line of Evidence (LOE) for Decision ID 162082, Turbidity
Region 6     
Blackwood Creek
 
LOE ID: 340858
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Blackwood Creek to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Turbidity.
Data Reference: Benthic, Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 6
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Water designated as MUN shall not contain concentrations of chemical constituents in excess of the maximum contaminant level (MCL) or secondary maximum contaminant level (SMCL) based upon drinking water standards specified in Title 22 of the California Code of Regulations. The Lahontan Basin Plan also has regionwide turbidity objective for other beneficial uses that states: Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10%.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the Lahontan Basin Plan's 'Chemical Constituents' objective. The Secondary MCL for turbidity is 5 NTU. Calculation of a numeric objective for other beneficial uses requires comparison with upstream or other background data which may not be available as part of the data used for water quality assessment.
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site: 634BLW002 (Blackwood Creek above Barker Pass Bridge).
Temporal Representation: The samples were collected between the dates of 2017-09-26 and 2017-09-26
Environmental Conditions:
QAPP Information: Generic SWAMP QAPrP
QAPP Information Reference(s): Generic SWAMP QAPrP
 
 
DECISION ID
69087
Region 6     
Blackwood Creek
 
Pollutant: Sedimentation/Siltation
Final Listing Decision: List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (being addressed by USEPA approved TMDL)(2016)
Revision Status Original
Sources: A Source Unknown
TMDL Name: Blackwood Creek sediment
TMDL Project Code: 182
Date TMDL Approved by USEPA: 07/11/2008
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Regional Board Conclusion:

This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle.

No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows:

In October 2007 the Lahontan RWQCB approved a sediment TMDL for Blackwood Creek, with an implementation program recognizing ongoing watershed restoration work by the U.S. Forest Service, Lake Tahoe Basin Management Unit. The TMDL was adopted under Resolution 6T-2007-0027 and did not involve a Basin Plan amendment. The USEPA approved the TMDL on July 11, 2008.
 
Regional Board Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
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 69087, Sedimentation/Siltation
Region 6     
Blackwood Creek
 
LOE ID: 4589
 
Pollutant: Sedimentation/Siltation
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
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):