David C. Twichell
VeeAnn A. Cross
2003
Chirp Seismic Survey Tracklines - Lake Mead 1999
vector digital data
David C. Twichell
VeeAnn A. Cross
2003
Mapping the floor of Lake Mead (Nevada and Arizona): Preliminary discussion and GIS data release
1.0
Open-File Report
03-320
Woods Hole Field Center, Woods Hole, MA
U.S. Geological Survey
Stephen D. Belew
seisnav_99
Lake Mead is a large interstate reservoir located in the Mojave Desert of southeastern Nevada and northwestern Arizona. It was impounded in 1935 by the construction of Hoover Dam and is one of a series of multi-purpose reservoirs on the Colorado River. The lake extends 183 km from the mouth of the Grand Canyon to Black Canyon, the site of Hoover Dam, and provides water for residential, commercial, industrial, recreational, and other non-agricultural users in communities across the southwestern United States. Extensive research has been conducted on Lake Mead, but a majority of the studies have involved determining levels of anthropogenic contaminants such as synthetic organic compounds, heavy metals and dissolved ions, furans/dioxins, and nutrient loading in lake water, sediment, and biota (Preissler, et al., 1998; Bevans et al, 1996; Bevans et al., 1998; Covay and Leiker, 1998; LaBounty and Horn, 1997; Paulson, 1981). By contrast, little work has focused on the sediments in the lake and the processes of deposition (Gould, 1951). To address these questions, sidescan-sonar imagery and high-resolution seismic-reflection profiles were collected throughout Lake Mead by the USGS in cooperation with researchers from University of Nevada Las Vegas (UNLV). These data allow a detailed mapping of the surficial geology and the distribution and thickness of sediment that has accumulated in the lake since the completion of Hoover Dam. Results indicate that the accumulation of post-impoundment sediment is primarily restricted to former river and stream beds that are now submerged below the lake while the margins of the lake appear to be devoid of post-impoundment sediment. The sediment cover along the original Colorado River bed is continuous and is typically greater than 10 m thick through much of its length. Sediment thickness in some areas exceeds 35 m while the smaller tributary valleys typically are filled with less than 4 m of sediment. Away from the river beds that are now covered with post-impoundment sediment, pre-impoundment alluvial deposits and rock outcrops are still exposed on the lake floor.
This GIS overlay indicates the tracklines along which chirp seismic-reflection profiles were collected during the 1999 survey.
en
19990514
19990525
ground condition
None planned
-114.857591
-114.589473
36.145382
36.018801
-114.857591-114.58947336.01880136.145382
General
seismic
navigation
polyline
chirp
subbottom
SIS-1000
U.S. Geological Survey
USGS
Coastal and Marine Geology Program
CMGP
Woods Hole Field Center
Open-File Report
OFR03-320
cruise serial number 99014
General
Nevada
Lake Mead
Hoover Dam
Boulder Basin
Mojave Desert
North AmericaUnited States
none
The U.S. Geological Survey must be referenced as the originator of the dataset in any future products or research derived from these data.
David C. Twichell
U.S. Geological Survey
Oceanographer
mailing and physical address
384 Woods Hole Rd.
Woods Hole
MA
02543-1598
508-548-8700 x2266
508-457-2310
dtwichell@usgs.gov
Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 3; ESRI ArcCatalog 8.2.0.700
ShapefileSynthetic organic compounds and carp endrocrinology and histology, Las Vegas Wash and Las Vegas and Callville bays of Lake Mead NevadaH.E. BevansS.L. GoodbredJ.F. MiesnerS.A. WatkinsT.S. GrossN.D. DenslowT. Choeb1996Water-Resources Investigations96-4266U.S. Geological SurveyWater quality in the Las Vegas Valley area and the Carson and Truckee River basins, Nevada and California, 1992-1996H.E. BevansM.S. LicoS.J. Lawrence1998Circular1170U.S. Geological SurveySynthetic organic compounds in water and bottom sediment from streams, detention basins, and sewage-treatment plant outfalls in Las Vegas Valley, Nevada, 1997K.J. CouvayT.J. Leiker1998Open-File Report98-633U.S. Geological SurveyArchive of Seismic-Reflection Data Collected During USGS Cruise Lake Mead 99014 in Lake Mead - Nevada and Arizona, 14-25May, 1999V.A. CrossD.C. Twichell2003Open-File Report03-003U.S. Geological SurveySome quantitative aspects of Lake Mead turbidity currentsH.R. Gould1951SEPM Special PublicationNo. 2Society of Economic Paleontologists and MineralogistsThe influence of drainage from the Las Vegas Valley on the limnology of Boulder Basin, Lake Mead, Arizona-NevadaJ.F. LaBountyM.J. Horn1997Journal of Lake and Reservoir Managementv. 13Nutrient management with hydroelectric dams on the Colorado RiverL.J. Paulson1981Technical Report#8Department of Biological Sciences, University of Nevada, Las Vegas, NevadaLake Mead Limnological Research CenterWater resources data, Nevada, water year 1998A.M. PreisslerG.A. RoachK.A. ThomasJ.W. Wilson1998Water Resources Data NevadaNV-98-1U.S. Geological Survey
These data have been checked to remove obviously erroneous data points.
These data represent the navigation for all the chirp seismic lines collected on this cruise.
Navigation was acquired and stored with the SIS-1000 chirp subbottom system. The navigation was corrected for instrument layback relative to the navigation antenna within the Hypack navigation system. A unique navigation point was sent to the acquisition system approximately every 10 seconds. These original navigation points are stored in the seismic data as UTM, Zone 11, NAD83 coordinates. These navigation positions reflect the best known position of the acquisition system. In other words, the layback of the instrument is taken into account for the positional fix.
This seismic navigation was then extracted from each individual trackline and projected into the geographic coordinate system using PROJ.
Evenden, 1990, Cartographic Projection Procedures for the UNIX Environment -- A User's Manual: Open-file Report 90-284
This file was then formatted to represent an Arc/Info generate format so that the lines could be imported into ArcView.
Within ArcView, additional attribute information describing each trackline was added.
Vector
String
80
SimplePolylineFALSE80TRUEFALSE
0.0002
0.0002
Decimal degrees
North American Datum of 1983
Geodetic Reference System 80
6378137.000000
298.257222
GCS_North_American_1983
seisnav_99
ArcView shapefile attribute table
ESRI
Feature Class80
FID
Internal feature number.
ESRI
Sequential unique whole numbers that are automatically generated.
FIDOID400
Shape
Feature geometry.
ESRI
Coordinates defining the features.
ShapeGeometry000
LINENUM
A numeric value indicating a line number.
VeeAnn A. Cross
0
505
LINENUMNumber6
FILENAME
Prefix of the filename assigned to each line of data collected.
Kenneth F. Parolski
character set
FILENAMEString10
FIRERATE
The rate at which the transducer "fired" or emitted the sonar pulse.
VeeAnn A. Cross
character set
FIRERATEString10
LENGTHM
The length of each line segment in meters.
Software computerd.
820
12350
meters
LENGTHMNumber163
SWATHSWATHString10The total swath (in meters) that was covered by the sidescan portion of the instrument. Related to firerate.Acquisition system.character setHOTLINKHOTLINKString50Path to the location of the hotlink file, uses a variable ($MYDATA) that can be set to make the data more portable.character set
David C. Twichell
U.S. Geological Survey
Oceanographer
mailing and physical address
384 Woods Hole Rd.
Woods Hole
MA
02543-1598
508-548-8700 x2266
508-457-2310
dtwichell@usgs.gov
Downloadable Data
These data were prepared by an agency of the United States Government. Neither the United States government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Although all data published in this report have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.
0.193
0.203
20030123
VeeAnn A. Cross
U.S. Geological Survey
Marine Geologist
mailing and physical address
384 Woods Hole Rd.
Woods Hole
MA
02543-1598
508-548-8700 x2251
508-457-2310
vatnipp@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time
none
none
enhttp://www.esri.com/metadata/esriprof80.htmlESRI Metadata Profile
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