Lake Tahoe Data Clearinghouse

Welcome to the Lake Tahoe Data Clearinghouse website. This text-only page is an attempt to summarize the information about Lake Tahoe and the data available on this website. It is a condensed form of the website, please visit the individual pages for detail and data download.

The site is designed for ease of use and navigation with the following layout on every page:

• USGS Lake Tahoe Data Clearinghouse logo on the top.
• Menu (navigation) bar to the right.
• Signature and speed bar at the bottom.

Welcome

This section is a good starting point for those interested in a variety of information concerning Lake Tahoe.

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Introduction

The Lake Tahoe Data Clearinghouse website, created and maintained by the U.S. Geological Survey (USGS) in partnership with Federal, State, tribal, and local agencies and groups, is a gateway to information and data on Lake Tahoe and its basin.

The primary goal of this clearinghouse is to facilitate the coordination of research, monitoring, and environmental-management activities in the Lake Tahoe Basin and to ensure the widest possible access to data and information resulting from such activities. The site is designed to ensure that all interested parties -- scientists, engineers, resource managers, developers, and the public -- have quick and easy access to Lake Tahoe data and information.

Users of this clearinghouse have access to a wide range of digital data and Geographic Information System (GIS) products. Examples include high-quality digital maps of digital elevation models, digital orthophoto quadrangles, digital line graphs, and digital raster graphics for the Lake Tahoe area. Some of the data resides on the USGS server at the Western Geographic Science Center, Menlo Park, California. The majority of the data and information, located in databases maintained by the partnering agencies, is accessible from this clearinghouse via links.

The site is organized into 3 different sections: (1) Welcome, (2) Digital Data, (3) General.

USGS

The USGS serves the Nation by providing reliable scientific information to:

• Describe and understand the Earth.
• Minimize loss of life and property from natural disasters.
• Manage water, biological, energy, and mineral resources.
• Enhance and protect our quality of life.

The mission is accomplished through data collection, research, comprehensive studies, and information services in the broad disciplines of hydrology, geology, biology, geography, and cartography.

The National Mapping Program of the USGS provides geographic and cartographic data, information, and related research to meet the broad requirements of the resource managers and Earth scientists in solving national challenges such as disaster response and mitigation, land and resource development, pollution abatement, transportation planning, urban development, and recreational use.

Lake Tahoe Initiative

On Saturday, July 26, 1997, President Clinton and Vice President Gore traveled to Incline Village, Nevada, to host the Lake Tahoe Presidential Forum.

Recognizing the unique nature of Lake Tahoe and its surrounding basin, the President signed an executive order in July 1997 directing Federal agencies to establish a formal interagency partnership charged with assuring coordination and efficient management of Federal program projects and activities with the Lake Tahoe Basin. The Executive Order also calls for the development of a linked natural-resources database and a Geographic Information System (GIS) capability.

Geography & History

Lake Tahoe is located along the border of California and Nevada. About one-third of the basin is in Nevada and two-thirds is in California. The basin is bounded by the Sierra Nevada to the west and the Carson Range to the east. The Lake Tahoe Basin was formed by geologic block (normal) faulting about 2 to 3 million years ago. The down-dropping of the Lake Tahoe Basin and the uplifting of the adjacent mountains resulted in dramatic topographic relief in the region. Mountain peaks rise to more than 10,000 ft (3,048 m) above sea level. The surface of Lake Tahoe has an average elevation of about 6,225 ft (1,897 m).

Lake Tahoe was occupied by the Washoe Tribe for many centuries. The Washoe Indians were hunting and fishing in the area long before General John C. Fremont encountered it in 1844 during his exploration of the Far West. Since then, public appreciation of Lake Tahoe has grown. Efforts were made during the 1912, 1913, and 1918 congressional sessions to designate the basin as a national park but were unsuccessful.

Lake Facts

Lake Tahoe is the second deepest lake in the United States and the tenth deepest in the world, with a maximum depth measured at 1,645 ft (501 m), average depth of 1,000 ft (305 m). The depth of Lake Tahoe changes every day as the lake level changes. The deepest measurement from the 1998 bathymetric survey was 1,637 ft (499 m) deep.

Lake Tahoe is about 22 mi (57 km) long and l2 mi (31 km) wide and has 72 mi (116 km) of shoreline and a surface area of 191 mi² (495 km²). The floor of the Lake Tahoe Basin is at an elevation of about 4,580 ft (1,396 m). With an average surface elevation of 6,225 ft (1,897 m) above sea level, Lake Tahoe is the highest lake of its size in the United States.

The water in Lake Tahoe could cover a flat area the size of California 14 in (36 cm) deep. This amount of water is enough to supply everyone in the United States with 50 gallons of water per day for 5 years. The amount of water that evaporates from the surface of Lake Tahoe every year could supply a city the size of Los Angeles for 5 years.

The water temperature near the surface generally cools to 40 to 50^oF (4.5 to 10^oC) during February and March and warms to 65 to 70^oF (18 to 21^oC) during August and September. Below a depth of 600 to 700 ft (183 to 213 m), the water temperature remains a constant 39^oF (4^oC).

Lake Tahoe has a water clarity of about 100 ft (30 m) deep. Factors contributing to its clarity include the following:

• 40 percent of the precipitation that falls into the Lake Tahoe Basin lands directly on the lake.
• Remaining precipitation drains through granitic soils, which are relatively sterile and create a good filtering system.

Digital Data

This section allows users to have easy access to a wide range of digital data and GIS products specific to Lake Tahoe. Examples include high-quality digital maps of bathymetry, hydrography, roads, vegetation cover, forests, timber, soils, and population for the Lake Tahoe Basin. The USGS provides four digital cartographic products (the 4 D's):
1. Digital Elevation Model (DEM).
2. Digital Orthophoto Quadrangle (DOQ).
3. Digital Line Graph (DLG).
4. Digital Raster Graphic (DRG).

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Data Downloads

GIS data depot for all available data downloads and metadata are linked from here. Downloadable data are available for the following topics: DEM, DOQ, DLG, DRG, Bathymetry, Landsat, Landcover, Census, and Soils.

The Lake Tahoe Basin covers 18 7.5-minute quadrangle maps. These 18 individual quads have been mosaicked together. The mosaicked files are more convenient for looking at areas throughout the basin or areas on the edge of two quadrangles. Data are in UTM NAD27 zone 10 projection.

Raw (original) data are in the following projections: data east of 120 degrees longitude are in UTM zone 11 and data west of 120 degrees longitude are in UTM zone 10. It is not possible to combine different projections in Geographic Information System (GIS), therefore, all data have been reprojected into one standard projection, UTM NAD27 zone 10 projection, for the Lake Tahoe Basin.

Here is an index of the individual quads that cover the Lake Tahoe Basin:

Truckee	Martis Peak	Mount Rose
Tahoe City	Kings Beach	Marlette Lake
Homewood	Meeks Bay	Glenbrook
Roundbound Valley	Emerald Bay	South Lake Tahoe
Pyramid Peak	Echo Lake	Freel Peak
Tragedy Spring	Caples Lake	Carson Pass

 

DEM

Cartographic/geographic data of elevations in xyz coordinates (view data in 3-dimensions).

A Digital Elevation Model (DEM) is digital cartographic/geographic data in raster form. The terrain elevations for ground positions are sampled at regularly spaced horizontal intervals. DEMs are derived from hypsographic data (contour lines) and/or photogrammetric methods using USGS 7.5-minute, 15-minute, 2-arc-second (30- by 60-minute), and 1-degree (1:250,000-scale) topographic quadrangle maps.

Data Downloads are available for 10-meter resolution, with or without the bathymetry data. Formats are available for ArcInfo export and JPEG with world file.

DOQ

Digital, uniform-scale image created from aerial photos (a photographic map).

A Digital Orthophoto Quadrangle (DOQ) is a digital, uniform-scale image created from aerial photos. It is a photographic map in which ground features are displayed in their true ground position, because relief displacements caused by the camera and terrain of an aerial photograph have been removed. It combines the image characteristics of a photograph with the geometric qualities of a map, thus it is possible to get direct measurements of distances, areas, angles, and positions from a DOQ.

Data Downloads are available in MrSID format with world file for year 1992 and 1998.

DLG

Cartographic data in vector format (geographic data in points, lines, and polygons).

A Digital Line Graph (DLG) is digital vector data representing cartographic information. DLGs contain a wide variety of information depicting geographic features (for example, hypsography, hydrography, boundaries, roads, utility lines, etc). DLGs are derived from hypsographic data (contour lines) using USGS 7.5-minute, 15-minute, 2-arc-second (30- by 60-minute), and 1:2 million-scale topographic quadrangle maps.

Data Downloads are available in Spatial Data Transfer Standard (SDTS), ARC/INFO export, and shapefile format for the following items: Hypsography, Hydrography, Vegetation, Roads, and Human-made features

DRG

A scanned version of the USGS 7.5-minute topographic map.

A Digital Raster Graphic (DRG) is a digital image (scanned version) of the USGS topographic map. DRGs are produced from USGS 1:24,000-, 1:24,000/1:25,000-, 1:63,360- (Alaska), 1:100,000-, and 1:250,000-scale topographic map series. The image inside the map neatline is georeferenced to the surface of the Earth and fit to the Universal Transverse Mercator (UTM) projection. The horizontal positional accuracy and datum of the DRG matches the accuracy and datum of the source map.

Data Downloads are available in GeoTIFF and MrSID formats with world files.

Bathymetry

Relief map and data of the lake floor of Lake Tahoe.

The Lake Tahoe Bathymetry survey was conducted on August 1998 using the latest-generation multibeam system by the USGS Western Region Coastal and Marine Geology Branch in cooperation with the Ocean Mapping Group (OMG) of the University of New Brunswick, Canada. The multibeam mapping system records both the bathymetric data (depth information) and the backscatter data (the strength of sound energy that bounces back). This information can help scientists identify the materials that make up the lake floor, such as rock, sand, or mud. New data can shed light on the history hidden by the waters of Lake Tahoe.

Data Downloads are available for the following items: High-resolution images from the bathymetric survey, Fly-by Movie, different types of bathymetry DEM files in ARC/INFO format.

Landsat 7

Satellite image of Earth's surface.

The USGS Landsat 7 satellite provides medium-resolution image information of the Earth's surface. It is a multispectral scanner that collects visible, near-infrared, short-wave, and thermal infrared frequency bands from the sun-lit Earth. Nominal ground sample distances or "pixel" sizes are 49 ft (15 m) in the panchromatic band; 98 ft (30 m) in the 6 visible, near and short-wave infrared bands; and 197 ft (60 m) in the thermal infrared band.

Data Downloads are available in GeoTIFF and IMAGINE format.

Landcover

Information of Earth's surface.

Data Downloads are available in GeoTIFF and ARC/INFO Grid format

Census

Population count.

Data Downloads are available in Spatial Data Transfer Standard (SDTS), ARC/INFO export, and shapefile formats.

Soils

A survey of the soil types in Lake Tahoe region.

Data Downloads are available for the SSURGO data in Spatial Data Transfer Standard (SDTS), ARC/INFO export, and shapefile formats.

General

This section consists of general interest information.

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Partners

Lake Tahoe Data Clearinghouse (LTDC) is a success because of the support and contributions of data and information from many different organizations working together. The Tahoe Federal Interagency Partnership brings together Federal, tribal, State and local agencies along with local groups and individuals that share a common goal of helping everyone enjoy the natural beauty of the area.

Here is a partial list of the groups involved with the Partnership:

• U.S. Department of Interior (DOI)
• U.S. Geological Survey (USGS)
• U.S. Forest Service (Lake Tahoe Basin Mangement Unit) (USFS)
• Natural Resources Conservation Service (NRCS)
• Tahoe Regional Planning Agency (TRPA)
• U.S. Department of Agriculture (USDA)
• U.S. Department of Transportation (DOT)
• U.S. Environmental Protection Agency (EPA)
• U.S. Postal Service (USPS)
• U.S. Army Corps of Engineers (USACE)
• State of California
• State of Nevada
• Washoe Tribe of Nevada and California
• University of California - Davis (UCDavis)
• University of Nevada, Reno
• Desert Research Institute (DRI)

Help Desk

Questions and Answers regarding the Lake Tahoe Data Clearinghouse. Listed are the questions asked. Please visit the Help Desk page for the answers.

• Who maintains this website?
• Can I link to this website?
• How can I view the data?
• Where do the data come from?
• What is a projection?
• The data are in what projection?
• How do I change projections?
• How can I view the DEM elevation information in Arcview?
• Is there similar data on other areas?
• How do I view data in MrSID format?
• Can I see objects on the bottom of Lake Tahoe?
• Is there a poster version of the bathymetry available?

Maps

This page contains miscellaneous maps from a variety of sources available across the internet. These maps are images rather than GIS ready data.

Maps available for road, quads locator, satellite, national map, slope, and bathymetry with steam monitoring sites.

Pictures

Views of Lake Tahoe from Earth and Space.

The beauty of nature becomes more and more precious to us as civilization continues to grow. The experience we gain from exploring nature imprints a special memory within our heart. The experience is refreshing as we allow the serenity to regenerate our mind and soul. Nature allows us to expand our knowledge toward understanding the foundation of life, and directs our focus toward finding appreciation and happiness in life's simple things.

Lake Tahoe is one of mother nature's most beautiful creations. From its alpine mountains to its flowing streams, Lake Tahoe is the place where we go to revive our mind and body. Its tranquil beauty refreshes and soothes us as we breathe in its refreshing scent. The awe-inspiring landscape opens our mind to a new perspective of life.

Although pictures cannot replace the experience of reality, it is a good place to start.

Sources

A list of sources and references to Lake Tahoe reports and links.

News and Reports -- News, reports, and research papers about Lake Tahoe.

Notes and Minutes -- Basin Watch, Lake Tahoe Interagency Monitoring Program (LTIMP), Upper Truckee River Focused Watershed Group (UTRFWG), Water Quality Working Group (WQWG).

Other Links -- Can't find what you need here? Try some other links about Lake Tahoe.

Note

All information provided is deemed reliable but is not guaranteed and should be independently verified.

Highlighted and (or) underlined terms are clickable and will take you to a new page. The footer symbol () marks links to external web sites and selected pages that will open in a new window, with a few exceptions. Exceptions include but are not limited to the following: no footer symbol () is placed before images and the signatures that have links to external web sites.

Thank You

Thank you for visiting the Lake Tahoe Data Clearinghouse website. The USGS and its partners designed this website for ease of use, and your feedback is encouraged. Please send your comments to T. Mathiasmeier at tmathias@usgs.gov, or click on Feedback at the bottom of each webpage to fill out the form.