The Lake Tahoe Interagency Monitoring Program (LTIMP) is an essential part of integrated science in the Lake Tahoe Basin and has provided long-term, consistent, reliable, and accessible tributary monitoring data for decades.
Deteriorating water quality and clarity in Lake Tahoe prompted the initiation of environmental programs in the Lake Tahoe basin. Water-quality data, especially nutrient and sediment data, for streams and ground-water aquifers that discharge to Lake Tahoe are needed to document the local and regional effectiveness of environmental programs and to assure compliance with California and Nevada water-quality management programs. The Lake Tahoe Interagency Monitoring Program (LTIMP) was started in 1979 to help understand why clarity was declining in Lake Tahoe. Currently, LTIMP stream monitoring is a partnership between the United States Geological Survey (USGS), the University of California-Davis (UC Davis), the Tahoe Regional Planning Agency (TRPA), the Lahontan Regional Water-Quality Control Board, and the California Tahoe Conservancy. The USGS continues to collect data necessary to assess the health of Lake Tahoe tributaries and ensure the data are publicly available.
Currently, water managers in Lake Tahoe are concerned about
- current tributary nutrient and suspended sediment concentrations and loads (status),
- assessing trends in nutrient and sediment concentrations and loads (trends), and
- what factors influence the observed status and trends.
Lake Tahoe Hydro Mapper
Lake Tahoe is a beautiful Alpine Lake in the Sierra Nevada. Known for its deep, clear water, Lake Tahoe is the second deepest lake in the United States, with a maximum depth of 1,645 feet. The average depth of Lake Tahoe is 1,000 feet.
Since the late 1980’s, USGS has collected discharge, sediment, and water quality data at seven major drainages as part of the Lake Tahoe Interagency Monitoring Program (LTIMP) . Continuous, real-time measurements of turbidity recently were added to LTIMP sites. Similarly, the U.S. Department of Agriculture, National Resources Conservation Service (NRCS) has conducted continuous snowpack and soil monitoring in basin headwaters, with daily snow measurements dating back to the late 1970’s or early 1980’s at most sites. These data can be combined with remotely sensed datasets available from USGS and National Aeronautics and Space Administration NASA and analyzed to determine the key factors controlling measured fine sediment and nutrient load in LTIMP streams draining to Lake Tahoe.
Lake Tahoe Basin data can now be accessed through the Lake Tahoe Hydro Mapper. The Hydro Mapper is an interactive map viewer which allows users to see real-time information on stream flow discharge, stage, nutrient, turbidity, sediment loads, and storage data. Data from NRCS Snow Telemetry (SNOTEL), National Weather Service Advanced Hydrologic Prediction Service and other local and regional hydrologic data with weather radar, watershed extents, and other ancillary geospatial data are included.
In addition to the data available in the Hydro Mapper, hydrologic functioning of the seven LTIMP watersheds are be assessed by determining key hydrologic conditions that drive daily variability of instream water quality at daily, monthly, and annual time intervals. The drivers may be a combination of dynamic (e.g., snowpack level, antecedent soil moisture or temperature, meteorological conditions) and static (e.g., terrain, geology, soil/vegetation) conditions within each watershed as well as various urban impacts and best management practices. Data about these key hydrologic conditions are available through this website.
Available Data
USGS Nevada Water Science Center scientists are collecting streamflow and water-quality data at pertinent Lake Tahoe tributaries to estimate nutrient and sediment loads to the lake and assess trends in stream water quality. Within the Lake Tahoe watershed, these data are collected at the following sites:
| USGS Site ID | USGS Site Name |
|---|---|
| 10336610 | UPPER TRUCKEE RV AT SOUTH LAKE TAHOE, CA |
| 10336645 | GENERAL C NR MEEKS BAY CA |
| 10336660 | BLACKWOOD C NR TAHOE CITY CA |
| 10336676 | WARD C AT HWY 89 NR TAHOE PINES CA |
| 10336780 | TROUT CK NR TAHOE VALLEY, CA |
| 10336698 | THIRD CK NR CRYSTAL BAY, NV |
| 10336700 | INCLINE CK NR CRYSTAL BAY, NV |
Monitoring Expansion Following the Caldor Fire
In water year 2022, LTIMP was expanded to monitor impacts of the Caldor fire. Over 10,000 acres were burned in the Upper Truckee and Trout Creek Watersheds. In response, the LTIMP program was expanded to increase the number of storm samples, add analyses of dissolved organic carbon, ammonium, and isotopes of fire-retardant related compounds with funding provided by TRPA. The expanded monitoring will continue for three years with a planned report to summarize the study results.
USGS hydrologist sampling at Trout Creek near Tahoe Valley, CA
Water-quality sample from Incline Creek near Crystal Bay, Nevada
Below are multimedia items associated with this project.
The Lake Tahoe Interagency Monitoring Program (LTIMP) is an essential part of integrated science in the Lake Tahoe Basin and has provided long-term, consistent, reliable, and accessible tributary monitoring data for decades.
Deteriorating water quality and clarity in Lake Tahoe prompted the initiation of environmental programs in the Lake Tahoe basin. Water-quality data, especially nutrient and sediment data, for streams and ground-water aquifers that discharge to Lake Tahoe are needed to document the local and regional effectiveness of environmental programs and to assure compliance with California and Nevada water-quality management programs. The Lake Tahoe Interagency Monitoring Program (LTIMP) was started in 1979 to help understand why clarity was declining in Lake Tahoe. Currently, LTIMP stream monitoring is a partnership between the United States Geological Survey (USGS), the University of California-Davis (UC Davis), the Tahoe Regional Planning Agency (TRPA), the Lahontan Regional Water-Quality Control Board, and the California Tahoe Conservancy. The USGS continues to collect data necessary to assess the health of Lake Tahoe tributaries and ensure the data are publicly available.
Currently, water managers in Lake Tahoe are concerned about
- current tributary nutrient and suspended sediment concentrations and loads (status),
- assessing trends in nutrient and sediment concentrations and loads (trends), and
- what factors influence the observed status and trends.
Lake Tahoe Hydro Mapper
Lake Tahoe is a beautiful Alpine Lake in the Sierra Nevada. Known for its deep, clear water, Lake Tahoe is the second deepest lake in the United States, with a maximum depth of 1,645 feet. The average depth of Lake Tahoe is 1,000 feet.
Since the late 1980’s, USGS has collected discharge, sediment, and water quality data at seven major drainages as part of the Lake Tahoe Interagency Monitoring Program (LTIMP) . Continuous, real-time measurements of turbidity recently were added to LTIMP sites. Similarly, the U.S. Department of Agriculture, National Resources Conservation Service (NRCS) has conducted continuous snowpack and soil monitoring in basin headwaters, with daily snow measurements dating back to the late 1970’s or early 1980’s at most sites. These data can be combined with remotely sensed datasets available from USGS and National Aeronautics and Space Administration NASA and analyzed to determine the key factors controlling measured fine sediment and nutrient load in LTIMP streams draining to Lake Tahoe.
Lake Tahoe Basin data can now be accessed through the Lake Tahoe Hydro Mapper. The Hydro Mapper is an interactive map viewer which allows users to see real-time information on stream flow discharge, stage, nutrient, turbidity, sediment loads, and storage data. Data from NRCS Snow Telemetry (SNOTEL), National Weather Service Advanced Hydrologic Prediction Service and other local and regional hydrologic data with weather radar, watershed extents, and other ancillary geospatial data are included.
In addition to the data available in the Hydro Mapper, hydrologic functioning of the seven LTIMP watersheds are be assessed by determining key hydrologic conditions that drive daily variability of instream water quality at daily, monthly, and annual time intervals. The drivers may be a combination of dynamic (e.g., snowpack level, antecedent soil moisture or temperature, meteorological conditions) and static (e.g., terrain, geology, soil/vegetation) conditions within each watershed as well as various urban impacts and best management practices. Data about these key hydrologic conditions are available through this website.
Available Data
USGS Nevada Water Science Center scientists are collecting streamflow and water-quality data at pertinent Lake Tahoe tributaries to estimate nutrient and sediment loads to the lake and assess trends in stream water quality. Within the Lake Tahoe watershed, these data are collected at the following sites:
| USGS Site ID | USGS Site Name |
|---|---|
| 10336610 | UPPER TRUCKEE RV AT SOUTH LAKE TAHOE, CA |
| 10336645 | GENERAL C NR MEEKS BAY CA |
| 10336660 | BLACKWOOD C NR TAHOE CITY CA |
| 10336676 | WARD C AT HWY 89 NR TAHOE PINES CA |
| 10336780 | TROUT CK NR TAHOE VALLEY, CA |
| 10336698 | THIRD CK NR CRYSTAL BAY, NV |
| 10336700 | INCLINE CK NR CRYSTAL BAY, NV |
Monitoring Expansion Following the Caldor Fire
In water year 2022, LTIMP was expanded to monitor impacts of the Caldor fire. Over 10,000 acres were burned in the Upper Truckee and Trout Creek Watersheds. In response, the LTIMP program was expanded to increase the number of storm samples, add analyses of dissolved organic carbon, ammonium, and isotopes of fire-retardant related compounds with funding provided by TRPA. The expanded monitoring will continue for three years with a planned report to summarize the study results.
USGS hydrologist sampling at Trout Creek near Tahoe Valley, CA
Water-quality sample from Incline Creek near Crystal Bay, Nevada
Below are multimedia items associated with this project.