U.S. Geological Survey
2003
Geophysical Surveys of Bear Lake, Utah-Idaho, September, 2002 - Bathymetry (5m contours)
Vector Data
Bear Lake is a tectonic lake that has existed for at
least several hundred thousand years. The lake basin
is a relatively simple half graben, a spoon-shaped depression
tilted toward the main fault on the east side of the lake. The U.S.
Geological Survey, in cooperation with researchers from several
universities, has been studying the sediments of Bear Lake since
1996. The general purpose of this effort is to reconstruct past
limnological conditions and regional climate on a range of timescales,
from hundreds of years to hundreds of thousands of years. This research
relates to a variety of human concerns, including water usage in
the Bear River basin. Past work has included several coring operations,
a seismic-reflection survey, sediment-trap deployments, a barge-mounted
drilling operation with the GLAD800 drill rig, and a variety of
other studies.
The objectives of the September, 2002 operations, preliminarily
reported here, were (1) to compile a detailed bathymetric map of
the lake using swath-mapping techniques, in order to provide baseline
data for a variety of applications and studies, and (2) to complete
a sidescan-sonar survey of the lake, providing a nearly complete
acoustic image of the lake floor. Limited amounts of subbottom acoustic-reflection
data (chrip) were also collected, along with samples of lake-floor
sediments representative of different kinds of backscatter patterns.
These surveys followed an earlier subbottom acoustic-reflection
survey (1997), using boomer and 3.5 kHz systems (S. M. Colman, unpublished
data).
The bathymetric contours will be used as a reference for depth information
within Bear Lake, Utah-Idaho. No bathymetric surveys have been conducted in
the Lake since the 1970's. This dataset represents the most up-to-date
bathymetric information for the area.
20020904
20020916
Publication Date
None planned
-111.5
-111.17
42.2
41.08
General
bathymetry
swath bathymetry
interferometry
U.S. Geological Survey
USGS
Coastal and Marine Geology Program
CMGP
Woods Hole Field Center
None
Bear Lake
Utah
Idaho
Western Lakes
North America
United States
None.
Bathymetry is not to be used for navigational purposes. The USGS asks to be referenced in any use of these data.
Jane F. Denny
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-457-2311
508-457-2310
jdenny@usgs.gov
These data are internally consistent; all data were acquired with an SEA 2000 Series Submetrix
interferometric sonar.
These data are were checked for consistency by plotting the point data
with the contoured surface and eliminating suprious and anomolous soundings.
These data are complete.
All navigation data were acquired using the Wide Area Augmentation System (WAAS),
a GPS-based navigation and landing system providing precision guidance to aircraft.
Horizontal accuracy of the WAAS network is assumed to be accurate < 3 meters.
Vertical accuracy is dependant on the navigation system. All navigation data were acquired
using the Wide Area Augmentation System (WAAS),
a GPS-based navigation and landing system providing precision guidance to aircraft.
The Wide Area Augmentation System (WAAS) is assumed to have a vertical accuracy of
+/- 5 meters. All ship motion was recorded by a TSS DMS 2-05 Attitude Sensor.
Bathymetric data were corrected for variations in the speed of sound throughout the
water column; sound velocity profiles were acquired at locations throughout the lake
and throughout the survey period. Attitude sensor and compass information were incorporated into
the header of the bathymetric data files using the SEA RTS2000 acquiistion and processing system.
The resultant data files were imported into SEA GRID2000 program and gridded to a
10 meter grid cell size.
20020916
Jane F. Denny
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-457-2311
508-457-2310
jdenny@usgs.gov
The SEA GRID2000 file was then exported as x,y,z. The weighgrid command within the University
of New Brunswick, Ocean Mapping Group, SwathEd software was used to interpolate the data to fill
in between line data gaps. An interpolation of 300 meter radius was used.
20020916
Jane F. Denny
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-457-2311
508-457-2310
jdenny@usgs.gov
The grid file was then converted to an ASCII Raster file and imported to ESRI ArcView 3.2.
20020916
Jane F. Denny
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-457-2311
508-457-2310
jdenny@usgs.gov
Contour data were generated from the bathymetric grid within ArcView. However,
in contouring the grid within ArcView, grid artifacts were carried over into
the contour data, The grid artifacts are primarily
a result of interpolating between line data gaps to generate a continuous
surface. Smoothing the contours and
further hand editting (based on non-interpolated bathymetric soundings)
generated a reasonable contour map. The final contour interval was chosen as five meter.
20020916
Jane F. Denny
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-457-2311
508-457-2310
jdenny@usgs.gov
Vector
0.000089992
0.000089992
decimal degrees
bathy_5m.shp
ESRI ArcView 3.2 shapefile
ESRI
Shape
Feature Geometry
ESRI
point
feature geometry name
Arcview
Length
feature geometry
ESRI
vector
feature geometry name
Arcview
ID
Internal Feature ID
ESRI
point
internal feature id
ESRI
Depth_m_
Contour Interval Labels
USGS
-65
-5
Contour
Contour Interval Labels
Lables with an 'a' signify vectors that
were editted by hand. The 'a' is a way
to distinguish hand editted vectors.
USGS
-65
-5
Jane F. Denny
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-457-2311
508-457-2310
jdenny@usgs.gov
Bathymetric Contours (5 meter interval)
Altough this data set and its lineage have been used by
the USGS, no warranty, expressed or implied, is made by
the USGS as to the accuracy of the data and/or it's related
materials. The act of distribution shall not constitute any
such warranty, and no resposibility is assumed by the
USGS in the use of these data or related items. Users must
assume resposibility for the proper use of this data. This
data should not be used at resolutions for which
it is not intended. This data has no been reviewed for
conformity with U.S. Geological Survey editorial standards,
or the North American Strigraphic code. Any use of trade,
product, or firm names is for descriptive purposes only
and does not imply endorsement by the US Government.
20020119
2002
Jane F. Denny
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-457-2311
508-457-2310
jdenny@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
None
None