| Water Body Name: | Trout Creek (below Hwy 50) |
| Water Body ID: | CAR6341003120020117091520 |
| Water Body Type: | River & Stream |
DECISION ID |
170475 |
Region 6 |
Trout Creek (below Hwy 50) |
||
| Pollutant: | Indicator Bacteria |
| Final Listing Decision: | Delist from 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list)(2018) |
| Revision Status | Revised |
| Reason for Delisting: | Applicable WQS attained; due to change in WQS |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | This pollutant is being considered for removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. One of 18 samples exceed the water quality objective for E. coli. (Fecal coliform lines of evidence used in previous indicator bacteria decisions in the Lahontan Region have been removed from decisions, starting in the 2026 Integrated Report, because the Lahontan Region's fecal coliform objective was removed from the Basin Plan in 2024). Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for removing this water segment-pollutant combination from the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of 18 samples exceed the water quality objective for E. coli. and this does not exceed the allowable frequency listed in Table 4.2 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. |
| Regional Board Decision Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be removed from the section 303(d) list because applicable water quality standards for the pollutant are not being exceeded. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | |
|
|||||
| LOE ID: | 336801 | ||||
| Pollutant: | Escherichia coli (E. coli) | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | STV | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 6 | ||||
| Number of Exceedances: | 1 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and the results are as follows: 1 of the 6 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: | Field, WQ from the Truckee Tahoe Snapshot Day 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): SLT-TROU-00 (Trout Creek at Mouth). | ||||
| Temporal Representation: | The samples were collected between the days of 2009-05-16 and 2021-05-15 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 4649 | ||||
| Pollutant: | Pathogens | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Not Recorded | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| 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): | |||||
|
|||||
| LOE ID: | 336797 | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) 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: | Field, WQ from the Truckee Tahoe Snapshot Day 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): SLT-TROU1-02 (Trout Creek downstream of Lake Tahoe Blvd.). | ||||
| Temporal Representation: | The samples were collected between the days of 2014-05-17 and 2014-05-17 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 336808 | ||||
| Pollutant: | Escherichia coli (E. coli) | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | STV | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 11 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and the results are as follows: 0 of the 11 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly. | ||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day 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): SLT-TROU-01 (Trout Creek at Bellevue Avenue). | ||||
| Temporal Representation: | The samples were collected between the days of 2008-05-10 and 2020-05-30 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
DECISION ID |
170482 |
Region 6 |
Trout Creek (below Hwy 50) |
||
| 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 was considered for placement on the section 303(d) list in a previous assessment cycle. 303(d) listing decisions made prior to 2006 were not held in an assessment database. Regional Board conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. 303(d) listing decisions made prior to 2006 were not held in an assessment database. Four lines of evidence are available in the administrative record to assess this pollutant. Eight of the 10 samples exceed the water quality objective. Trout Creek (below Hwy 50) is a tributary to Lake Tahoe. The Lake Tahoe TMDL includes an implementation plan that identifies actions that resource management agencies, Lake Tahoe municipalities (El Dorado and Placer Counties, City of South Lake Tahoe) and California Department of Transportation (CalTrans) must take to reduce inputs of nutrients (nitrogen and phosphorus) and fine sediment. On the ground efforts required by the Lake Tahoe TMDL that focus on (1) stabilizing disturbed areas within the forested uplands, (2) restoring eroding stream channels, and (3) managing and treating urban uplands (e.g. street sweeping, installing and maintaining infiltration and stormwater treatment facilities) will also achieve pollutant load reductions in waters tributary to Lake Tahoe. The largest source of nitrogen in the Lake Tahoe (and Trout Creek) watershed is transportation-related emissions that lead to atmospheric nitrogen deposition. The Lake Tahoe TMDL also includes implementation measures to reduce atmospheric nitrogen sources. The Tahoe Regional Planning Agency leads 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 Trout Creek watershed. Furthermore, Federal, State, and larger local restoration agencies have well defined multi objective watershed restoration programs. These programs include maintenance activities (e.g., fuels reduction projects and restoring small disturbed sites) that are underway, or planned and expected, within the forested uplands of this watershed. Implementation of these measures will reduce or avoid increases in fine sediment and nutrient loads to Lake Tahoe and its tributaries including Trout Creek below Hwy 50. Finally, recent restoration efforts directly upstream of this segment of Trout Creek completed by the City of South Lake Tahoe have restored geomorphic and hydrologic function and treatment of bankfull flows to help reduce nitrogen loading to this segment of Trout Creek. Pollutant load reductions within Trout Creek (below Hwy 50) 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 Trout Creek (below Hwy 50) 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 Trout Creek (below Hwy 50) 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 applicable water quality standards for the pollutant are being exceeded. |
| State Board Review of Regional Board Conclusion and Recommendation: | Pollutant load reductions within Trout Creek (below Hwy 50) 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 Trout Creek (below Hwy 50) 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 Trout Creek (below Hwy 50) 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: | |
|
|||||
| LOE ID: | 343127 | ||||
| Pollutant: | Total Nitrogen as N | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Not Recorded | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality threshold for Nitrogen, Total |
||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day for the 2026 Integrated Report in Region 6 | ||||
| SWAMP Data: | Non-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: Trout Creek at Bellevue Avenue (SLT-TROU-01) | ||||
| Temporal Representation: | The samples were collected between the dates of 2013-05-11 and 2013-05-11 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 343089 | ||||
| Pollutant: | Total Nitrogen as N | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Total | ||||
| Beneficial Use: | Cold Freshwater Habitat | ||||
| Number of Samples: | 5 | ||||
| Number of Exceedances: | 4 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data to determine beneficial use support and results are as follows: 4 of 5 samples exceeded the water quality threshold for Nitrogen, Total |
||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day for the 2026 Integrated Report in Region 6 | ||||
| SWAMP Data: | Non-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: Trout Creek at Bellevue Avenue (SLT-TROU-01) | ||||
| Temporal Representation: | The samples were collected between the dates of 2016-05-14 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 343124 | ||||
| Pollutant: | Total Nitrogen as N | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data to determine beneficial use support and results are as follows: 1 of 2 samples exceeded the water quality threshold for Nitrogen, Total |
||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day for the 2026 Integrated Report in Region 6 | ||||
| SWAMP Data: | Non-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: Trout Creek at Mouth (SLT-TROU-00) | ||||
| Temporal Representation: | The samples were collected between the dates of 2019-05-18 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 343090 | ||||
| Pollutant: | Total Nitrogen as N | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Not Recorded | ||||
| Beneficial Use: | Cold Freshwater Habitat | ||||
| Number of Samples: | 2 | ||||
| Number of Exceedances: | 2 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data to determine beneficial use support and results are as follows: 2 of 2 samples exceeded the water quality threshold for Nitrogen, Total |
||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day for the 2026 Integrated Report in Region 6 | ||||
| SWAMP Data: | Non-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: Trout Creek at Mouth (SLT-TROU-00) | ||||
| Temporal Representation: | The samples were collected between the dates of 2009-05-16 and 2010-05-22 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 4648 | ||||
| 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): | |||||
DECISION ID |
163646 |
Region 6 |
Trout Creek (below Hwy 50) |
||
| 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: | 08/22/2011 |
| 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 SECTION of the Listing Policy. Under SECTION of the Policy, a minimum of one line of evidence is needed to assess listing status. Five lines of evidence are available in the administrative record to assess this pollutant. 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. 15 of 15 samples exceeded the objective and these exceed the allowable frequency listed in Table 4.1 of the Listing Policy. 4. The Lake Tahoe Nutrients/Sediment TMDL was approved by USEPA on 08/22/2011. 5. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. |
| Regional Board Decision Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | |
|
|||||
| LOE ID: | 343233 | ||||
| Pollutant: | Phosphorus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Total | ||||
| Beneficial Use: | Cold Freshwater Habitat | ||||
| Number of Samples: | 5 | ||||
| Number of Exceedances: | 5 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data to determine beneficial use support and results are as follows: 5 of 5 samples exceeded the water quality threshold for Phosphorus as P |
||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day 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: Trout Creek at Bellevue Avenue (SLT-TROU-01) | ||||
| Temporal Representation: | The samples were collected between the dates of 2012-05-12 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 343235 | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D 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: | Field, WQ from the Truckee Tahoe Snapshot Day 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: Trout Creek downstream of Lake Tahoe Blvd. (SLT-TROU1-02) | ||||
| Temporal Representation: | The samples were collected between the dates of 2002-05-04 and 2002-05-04 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 343672 | ||||
| Pollutant: | Phosphorus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Total | ||||
| Beneficial Use: | Cold Freshwater Habitat | ||||
| Number of Samples: | 2 | ||||
| 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 2 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: TROUT C A SOUTH LAKE TAHOE CA (USGS-10336790) | ||||
| Temporal Representation: | The samples were collected between the dates of 2017-01-08 and 2021-09-17 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | NA | ||||
| QAPP Information Reference(s): | QAPP for USGS Data Collected during the 2026 Integrated Report Cycle | ||||
|
|||||
| LOE ID: | 343223 | ||||
| Pollutant: | Phosphorus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Total | ||||
| Beneficial Use: | Cold Freshwater Habitat | ||||
| Number of Samples: | 7 | ||||
| Number of Exceedances: | 7 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data to determine beneficial use support and results are as follows: 7 of 7 samples exceeded the water quality threshold for Phosphorus as P |
||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day 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: Trout Creek at Mouth (SLT-TROU-00) | ||||
| Temporal Representation: | The samples were collected between the dates of 2004-05-22 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 4650 | ||||
| Pollutant: | Phosphorus | ||||
| 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): | |||||
DECISION ID |
162048 |
Region 6 |
Trout Creek (below Hwy 50) |
||
| Pollutant: | Alkalinity as CaCO3 |
| 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: | |
|
|||||
| LOE ID: | 337842 | ||||
| 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 Trout Creek (below Hwy 50) 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: 634TPA050 (Trout Creek 634011050 Trend Panel A). | ||||
| Temporal Representation: | The samples were collected between the dates of 2018-09-19 and 2018-09-19 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Generic SWAMP QAPrP | ||||
| QAPP Information Reference(s): | Generic SWAMP QAPrP | ||||
DECISION ID |
171011 |
Region 6 |
Trout Creek (below Hwy 50) |
||
| Pollutant: | Benthic Community Effects |
| 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: | 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. One line of evidence evaluating benthic-macroinvertebrate bioassessment data is available in the administrative record to assess this indicator. One of one benthic-macroinvertebrate samples exceed the California Stream Condition Index (CSCI) impairment threshold. However, a minimum of two benthic-macroinvertebrate samples are needed to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against 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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. One of one benthic-macroinvertebrate bioassessment samples had CSCI scores below 0.79. The available information is insufficient to determine whether the waterbody/pollutant combination should be placed on the 303(d) List of impaired waters at this time. 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: | |
|
|||||
| LOE ID: | 352862 | ||||
| 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 634TPA050 to determine beneficial use support and the results are as follows: 1 of 1 samples exceeded the water quality standard. CSCI scores were from 0.55688 to 0.55688 . | ||||
| 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: 634TPA050 (Trout Creek 634011050 Trend Panel A). | ||||
| Temporal Representation: | Samples were collected from 2018-09-19 to 2018-09-19. | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Generic SWAMP QAPrP | ||||
| QAPP Information Reference(s): | Generic SWAMP QAPrP | ||||
DECISION ID |
170478 |
Region 6 |
Trout Creek (below Hwy 50) |
||
| Pollutant: | Nitrogen, Nitrate |
| 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. |
|
|||||
| LOE ID: | 338960 | ||||
| Pollutant: | Nitrate as Nitrate (NO3) | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Not Recorded | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Nitrate as NO3. | ||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day for the 2026 Integrated Report in Region 6 | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The California Maximum Contaminant Level for Nitrate incorporated by reference in the Water Quality Control Plan, Lahontan Region is 45000 ug/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: SLT-TROU-01 (Trout Creek at Bellevue Avenue). | ||||
| Temporal Representation: | The samples were collected between the dates of 2012-05-12 and 2012-05-12 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
DECISION ID |
162045 |
Region 6 |
Trout Creek (below Hwy 50) |
||
| Pollutant: | Oxygen, Dissolved |
| 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: | 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. Six lines of evidence are available in the administrative record to assess this parameter: 5 which assess dissolved oxygen concentration data and 1 which assesses dissolved oxygen percent saturation data. Zero of 28 samples are below the objective for minimum dissolved oxygen concentration. One of 1 samples is 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 28 samples are below the objective for minimum dissolved oxygen concentration. One of 1 samples is below the objective for minimum dissolved oxygen percent saturation. This does not exceed the allowable number of exceedances 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. 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: | |
|
|||||
| LOE ID: | 339290 | ||||
| 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 Trout Creek (below Hwy 50) 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: 634TPA050 (Trout Creek 634011050 Trend Panel A). | ||||
| Temporal Representation: | The samples were collected between the dates of 2018-09-19 and 2018-09-19 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Generic SWAMP QAPrP | ||||
| QAPP Information Reference(s): | Generic SWAMP QAPrP | ||||
|
|||||
| LOE ID: | 339147 | ||||
| Pollutant: | Oxygen, Dissolved | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Cold Freshwater Habitat | ||||
| Number of Samples: | 13 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 13 samples exceeded the water quality threshold for Oxygen, Dissolved. | ||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU-01 (Trout Creek at Bellevue Avenue). | ||||
| Temporal Representation: | The samples were collected between the dates of 2006-05-20 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 339385 | ||||
| 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 Trout Creek (below Hwy 50) 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: 634TPA050 (Trout Creek 634011050 Trend Panel A). | ||||
| Temporal Representation: | The samples were collected between the dates of 2018-09-19 and 2018-09-19 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Generic SWAMP QAPrP | ||||
| QAPP Information Reference(s): | Generic SWAMP QAPrP | ||||
|
|||||
| LOE ID: | 341609 | ||||
| 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 USGS California Water Science Center data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 1 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-10336790 (TROUT C A SOUTH LAKE TAHOE CA). | ||||
| Temporal Representation: | The samples were collected between the dates of 2021-09-17 and 2021-09-17 | ||||
| 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 | ||||
|
|||||
| LOE ID: | 339191 | ||||
| Pollutant: | Oxygen, Dissolved | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Oxygen, Dissolved. | ||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU1-02 (Trout Creek downstream of Lake Tahoe Blvd.). | ||||
| Temporal Representation: | The samples were collected between the dates of 2002-05-04 and 2006-05-20 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 339113 | ||||
| Pollutant: | Oxygen, Dissolved | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Cold Freshwater Habitat | ||||
| Number of Samples: | 11 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 11 samples exceeded the water quality threshold for Oxygen, Dissolved. | ||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU-00 (Trout Creek at Mouth). | ||||
| Temporal Representation: | The samples were collected between the dates of 2003-05-10 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
DECISION ID |
170480 |
Region 6 |
Trout Creek (below Hwy 50) |
||
| Pollutant: | Specific Conductivity |
| 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: | 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 the 29 samples exceed the objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 29 samples exceeded the objective 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: | |
|
|||||
| LOE ID: | 341890 | ||||
| Pollutant: | Specific Conductivity | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| Number of Samples: | 3 | ||||
| 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 Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 3 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-10336790 (TROUT C A SOUTH LAKE TAHOE CA). | ||||
| Temporal Representation: | The samples were collected between the dates of 2017-01-09 and 2021-09-17 | ||||
| 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 | ||||
|
|||||
| LOE ID: | 340678 | ||||
| Pollutant: | Specific Conductivity | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| Number of Samples: | 11 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 11 samples exceeded the water quality threshold for SpecificConductivity. | ||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU-00 (Trout Creek at Mouth). | ||||
| Temporal Representation: | The samples were collected between the dates of 2003-05-10 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 340647 | ||||
| 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 Trout Creek (below Hwy 50) 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: 634TPA050 (Trout Creek 634011050 Trend Panel A). | ||||
| Temporal Representation: | The samples were collected between the dates of 2018-09-19 and 2018-09-19 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Generic SWAMP QAPrP | ||||
| QAPP Information Reference(s): | Generic SWAMP QAPrP | ||||
|
|||||
| LOE ID: | 340332 | ||||
| Pollutant: | Specific Conductivity | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| Number of Samples: | 12 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 12 samples exceeded the water quality threshold for SpecificConductivity. | ||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU-01 (Trout Creek at Bellevue Avenue). | ||||
| Temporal Representation: | The samples were collected between the dates of 2009-05-16 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 340397 | ||||
| Pollutant: | Specific Conductivity | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for SpecificConductivity. | ||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU1-02 (Trout Creek downstream of Lake Tahoe Blvd.). | ||||
| Temporal Representation: | The samples were collected between the dates of 2002-05-04 and 2014-05-17 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
DECISION ID |
162046 |
Region 6 |
Trout Creek (below Hwy 50) |
||
| Pollutant: | pH |
| 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: | |
|
|||||
| LOE ID: | 339901 | ||||
| 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 Trout Creek (below Hwy 50) 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: 634TPA050 (Trout Creek 634011050 Trend Panel A). | ||||
| Temporal Representation: | The samples were collected between the dates of 2018-09-19 and 2018-09-19 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Generic SWAMP QAPrP | ||||
| QAPP Information Reference(s): | Generic SWAMP QAPrP | ||||
|
|||||
| LOE ID: | 341677 | ||||
| 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 Trout Creek (below Hwy 50) 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: | 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-10336790 (TROUT C A SOUTH LAKE TAHOE CA). | ||||
| Temporal Representation: | The samples were collected between the dates of 2021-09-17 and 2021-09-17 | ||||
| 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 | ||||
|
|||||
| LOE ID: | 340017 | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 12 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: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU-01 (Trout Creek at Bellevue Avenue). | ||||
| Temporal Representation: | The samples were collected between the dates of 2006-05-20 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 339696 | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 3 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: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU1-02 (Trout Creek downstream of Lake Tahoe Blvd.). | ||||
| Temporal Representation: | The samples were collected between the dates of 2002-05-04 and 2014-05-17 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 339659 | ||||
| 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 Trout Creek (below Hwy 50) 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: 634TPA050 (Trout Creek 634011050 Trend Panel A). | ||||
| Temporal Representation: | The samples were collected between the dates of 2018-09-19 and 2018-09-19 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Generic SWAMP QAPrP | ||||
| QAPP Information Reference(s): | Generic SWAMP QAPrP | ||||
|
|||||
| LOE ID: | 339647 | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 10 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: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU-00 (Trout Creek at Mouth). | ||||
| Temporal Representation: | The samples were collected between the dates of 2003-05-10 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 340170 | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 3 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: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU1-02 (Trout Creek downstream of Lake Tahoe Blvd.). | ||||
| Temporal Representation: | The samples were collected between the dates of 2002-05-04 and 2014-05-17 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 341716 | ||||
| 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 Trout Creek (below Hwy 50) 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: | 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-10336790 (TROUT C A SOUTH LAKE TAHOE CA). | ||||
| Temporal Representation: | The samples were collected between the dates of 2021-09-17 and 2021-09-17 | ||||
| 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 | ||||
|
|||||
| LOE ID: | 340132 | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 10 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: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU-00 (Trout Creek at Mouth). | ||||
| Temporal Representation: | The samples were collected between the dates of 2003-05-10 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 340059 | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 12 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: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU-01 (Trout Creek at Bellevue Avenue). | ||||
| Temporal Representation: | The samples were collected between the dates of 2006-05-20 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
DECISION ID |
163645 |
Region 6 |
Trout Creek (below Hwy 50) |
||
| Pollutant: | Chloride |
| Final Listing Decision: | List on 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: | New Decision |
| 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. Ten of the 10 samples exceed the objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Ten of 10 samples exceed the objective 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: | |
|
|||||
| LOE ID: | 342760 | ||||
| Pollutant: | Chloride | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Dissolved | ||||
| Beneficial Use: | Cold Freshwater Habitat | ||||
| Number of Samples: | 6 | ||||
| Number of Exceedances: | 6 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data to determine beneficial use support and results are as follows: 6 of 6 samples exceeded the water quality threshold for Chloride |
||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day for the 2026 Integrated Report in Region 6 | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The Basin Plan objective for Chloride in this water body is 0.15 (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: Trout Creek at Bellevue Avenue (SLT-TROU-01) | ||||
| Temporal Representation: | The samples were collected between the dates of 2015-05-16 and 2020-05-30 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 342781 | ||||
| Pollutant: | Chloride | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Dissolved | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality threshold for Chloride |
||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day for the 2026 Integrated Report in Region 6 | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The Basin Plan objective for Chloride in this water body is 0.15 (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: Trout Creek downstream of Lake Tahoe Blvd. (SLT-TROU1-02) | ||||
| Temporal Representation: | The samples were collected between the dates of 2014-05-17 and 2014-05-17 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 342775 | ||||
| Pollutant: | Chloride | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Dissolved | ||||
| Beneficial Use: | Cold Freshwater Habitat | ||||
| Number of Samples: | 3 | ||||
| Number of Exceedances: | 3 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data to determine beneficial use support and results are as follows: 3 of 3 samples exceeded the water quality threshold for Chloride |
||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day for the 2026 Integrated Report in Region 6 | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The Basin Plan objective for Chloride in this water body is 0.15 (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: Trout Creek at Mouth (SLT-TROU-00) | ||||
| Temporal Representation: | The samples were collected between the dates of 2014-05-17 and 2020-05-30 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
DECISION ID |
69978 |
Region 6 |
Trout Creek (below Hwy 50) |
||
| 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 |
| 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. The TMDL completion date for this decision has been updated to 2031. |
| 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. |
|
|||||
| LOE ID: | 4647 | ||||
| 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 |
162047 |
Region 6 |
Trout Creek (below Hwy 50) |
||
| Pollutant: | Turbidity |
| Final Listing Decision: | List on 303(d) list (being addressed by USEPA approved TMDL) |
| Last Listing Cycle's Final Listing Decision: | New Decision |
| Revision Status | Revised |
| Sources: | Channel Erosion | Construction/Land Development | Erosion/Siltation |
| TMDL Name: | Lake Tahoe Nutrients/Sediment |
| TMDL Project Code: | 198 |
| Date TMDL Approved by USEPA: | 08/22/2011 |
| 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 SECTION of the Listing Policy. Under SECTION of the Policy, a minimum of one line of evidence is needed to assess listing status. Five lines of evidence are available in the administrative record to assess this pollutant. 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. 9 of 46 samples exceeded the objective and these exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. The Lake Tahoe Nutrients/Sediment TMDL was approved by USEPA on 08/22/2011. 5. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. |
| Regional Board Decision Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should 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: | |
|
|||||
| LOE ID: | 340904 | ||||
| Pollutant: | Turbidity | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Total | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| 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 League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Turbidity. | ||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU1-02 (Trout Creek downstream of Lake Tahoe Blvd.). | ||||
| Temporal Representation: | The samples were collected between the dates of 2002-05-04 and 2014-05-17 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 340937 | ||||
| Pollutant: | Turbidity | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Total | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| Number of Samples: | 11 | ||||
| Number of Exceedances: | 1 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 1 of 11 samples exceeded the water quality threshold for Turbidity. | ||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU-01 (Trout Creek at Bellevue Avenue). | ||||
| Temporal Representation: | The samples were collected between the dates of 2009-05-16 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||
|
|||||
| LOE ID: | 340806 | ||||
| Pollutant: | Turbidity | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Total | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| Number of Samples: | 20 | ||||
| Number of Exceedances: | 3 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed Upper Truckee Marsh 319 Monitoring data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 3 of 20 samples exceeded the water quality threshold for Turbidity. | ||||
| Data Reference: | Field from the Section 319h Grants 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: 634TCSTPUD (Trout Creek at STPUD Gage). | ||||
| Temporal Representation: | The samples were collected between the dates of 2014-11-17 and 2016-03-21 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Upper Truckee Marsh 319 QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - UpperTruckeeMarsh319QAPP - Upper Truckee Marsh 319 Monitoring - 402635 | ||||
|
|||||
| LOE ID: | 341970 | ||||
| Pollutant: | Turbidity | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Total | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| Number of Samples: | 3 | ||||
| Number of Exceedances: | 3 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed USGS California Water Science Center data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 3 of 3 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-10336790 (TROUT C A SOUTH LAKE TAHOE CA). | ||||
| Temporal Representation: | The samples were collected between the dates of 2017-01-09 and 2021-09-17 | ||||
| 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 | ||||
|
|||||
| LOE ID: | 340987 | ||||
| Pollutant: | Turbidity | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Total | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| Number of Samples: | 10 | ||||
| Number of Exceedances: | 2 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed League to Save Lake Tahoe Truckee Tahoe Snapshot D data for Trout Creek (below Hwy 50) to determine beneficial use support and results are as follows: 2 of 10 samples exceeded the water quality threshold for Turbidity. | ||||
| Data Reference: | Field, WQ from the Truckee Tahoe Snapshot Day 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: SLT-TROU-00 (Trout Creek at Mouth). | ||||
| Temporal Representation: | The samples were collected between the dates of 2003-05-10 and 2021-05-15 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Tahoe Truckee Snapshot QAPP | ||||
| QAPP Information Reference(s): | Lahontan Water Board - TahoeTruckeeSnapshotQAPP - League to Save Lake Tahoe Truckee Tahoe Snapshot D - 402634 | ||||