New maps change thinking about Great Salt Lake

http://www.usgs.gov/newsroom/article.asp?ID=1605

The U.S. Geological Survey (USGS) has recently released the second of
two maps defining the bottom surface of Great Salt Lake, Utah. These
mapping efforts were the first detailed, systematic surveys of the lake.

These new maps provide information about the physical shape of the lake
and affect our understanding of the transport of salt and contaminants
in the lake, the chemistry of the lake, the geologic history of the
lake, and ecological implications of water depth and volume.

High tech mapping technology was used in the new maps and includes a
high-definition fathometer, real-time differential global positioning
system, and depth-discrete sound-velocity corrections. About 12.8
million depth measurements were collected along more than 1,695 miles
(2,728 kilometers) of survey transects and were used in defining the
bathymetry of the lake. This work was done during 2002-2006 in
cooperation with the Utah Division of Wildlife Resources and the
Division of Forestry, Fire, and State Lands.

Efforts are already underway to use this new data for lake circulation
modeling, chemical transport, and in helping to better define the
relation between the bathymetry of the lake and its biological and
ecological components.
Great Salt Lake is actually two basins separated by a low-lying
fault-controlled ridge extending from Promontory Point southwest to Hat
Island. During recent history, the ridge has been submerged and
consequently has not been shown in detail on any previous maps. Both
basins trend primarily north-south and are bounded on the east edge by
fault-related scarps. The deepest natural part of the lake is in the
north basin at an altitude of about 4,167 feet or about 30 feet below
the current lake surface. The Union Pacific Railroad causeway cuts
through the north basin and through the deepest part of the lake
segmenting the north basin into two separate parts. For additional
information, including digital images of the maps, lake-bottom features,
and examples of sonar returns, please contact Rob Baskin at the USGS
Utah Water Science Center.

Digital copies of the bathymetric maps and accompanying informational
sheets for both the north and south parts of Great Salt Lake (in PDF
format) can be found on the Internet.

Bathymetric Map of the North Part of Great Salt Lake, Utah, 2006.
http://pubs.usgs.gov/sim/2006/2954/

Calculation of Area and Volume for the North Part of Great Salt Lake, Utah.
http://pubs.usgs.gov/of/2006/1359/

Bathymetric Map of the South Part of Great Salt Lake, Utah, 2005.
http://pubs.usgs.gov/sim/2005/2894/

Calculation of Area and Volume for the South Part of Great Salt Lake, Utah.
http://pubs.usgs.gov/of/2005/1327/



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