David C. Twichell
VeeAnn A. Cross
2003
Enhanced TIFF Sidescan-Sonar Mosaic of Las Vegas Wash - Lake Mead, Nevada: Geographic Coordinates
lvwash_eng.tifremote-sensing imageMapping the floor of Lake Mead (Nevada and Arizona): Preliminary discussion and GIS data releaseDavid C. TwichellVeeAnn A. CrossStephen D. Belew2003Open-File Report03-320U.S. Geological SurveyWoods Hole Field Center, Woods Hole, MA1.0
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 sidescan-sonar imagery is used to map the morphology of the lake floor and determine the extent of sediment distribution on the lake floor.
en
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ground condition
None planned
-114.877684
-114.805622
36.139662
36.109843
-114.877684-114.80562236.10984336.139662
GeneralCMGPCoastal and Marine Geology ProgramimagesmosaicOFR03-320Open-File Reportreservoirsidescansidescan sonarTIFFU.S. Geological SurveyUSGSWoods Hole Field CenterGeneralLake MeadLas VegasLas Vegas WashMojave DesertNevadaUnited StatesNorth America
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. TwichellU.S. Geological SurveyOceanographermailing and physical address384 Woods Hole Rd.Woods HoleMA02543-1598(508) 548-8700 x2266(508) 457-2310dtwichell@usgs.gov
Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 4; ESRI ArcCatalog 8.2.0.700
Raster DatasetSynthetic 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 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
All of these data were collected with the same sidescan-sonar towfish - the Edgetech DF1000. All data were collected as 16-bit, 200m swath, 1024 pixels/side.
All imagery necessary to map the lake floor of interest in this particular study was used.
The ship was navigated with P-CODE GPS. The towfish was deployed at approximately the same depth each day, with little variation during the course of the survey. Due to the shipboard configuration, the navigation antennae was placed at the approximate layback position of the towfish, therefore range to fish errors are assumed to be negligible.
Sidescan sonar imagery was collected using an Edgetech DF1000 sidescan sonar system and logged to a Triton QMIPS data logging computer. All of the data were collected at a 200m swath, 1024 pixels/side, 16-bit. The digital sidescan data were then processed and mapped to provide proper geographic locations of features identified in the imagery. The processing steps included subsampling the raw sidescan data using a median filtering routine to suppress speckle noise and reduce file size, and corrrect for slant-range distortion, signal attentuation, and dropped sonar lines using XSonar (Danforth et al., 1991).
Danforth, W.W., O'Brien, T.F., and Schwab, W.C., 1991, USGS image processing system: near real-time mosaicking of high-resolutoin sidescan-sonar data: Sea Technology, Jan., 1991, p. 54-59.
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VeeAnn A. Cross
U.S. Geological Survey
Marine Geologist
mailing and physical address
384 Woods Hole Rd.
Woods Hole
MA
02543
USA
508-548-8700 x2251
508-457-2310
vatnipp@usgs.gov
The imagery was mapped into its proper geographic location using techniques summarized by Paskevich (1996). Individual sidescan swaths were mapped with each pixel geographically positioned at a resolution of 1 m/pixel.
Paskevich, V.F., 1996, MAPIT: An improved method for mapping digital sidescan sonar data using the Woods HOle Image Processing System (WHIPS) software: U.S. Geological Survey Open-File Report 96-281, 73p.
20000600
VeeAnn A. Cross
U.S. Geological Survey
Marine Geologist
mailing and physical address
384 Woods Hole Rd.
Woods Hole
MA
02543
USA
508-548-8700 x2251
508-457-2310
vatnipp@usgs.gov
Non-overlapping swaths were then brought into the remote sensing software package PCI. The techniques for generating the composite digital sidscan mosaic are summarized by Paskevich (1992). A root stretch from 0-254 was applied to the sidescan image. The imagery portion was then cut out and written to a PCI channel with a white background. By doing this, within ArcView the user can turn the 255 pixel value to transparent and only display the actual sidescan imagery. This enhanced image was then exported from PCI as a TIFF image with an associated world file for georeferencing purposes.
Paskevich, V.F., 1992, Digital mapping of sidescan sonar data with the Woods Hole Image Processing System software: U.S. Geological Survey Open-File Report 92-536, 87p.
20000600
David C. Twichell
U.S. Geological Survey
Oceanographer
mailing and physical address
384 Woods Hole Rd.
Woods Hole
MA
02543
USA
508-548-8700 x2266
508-457-2310
dtwichell@usgs.gov
The UTM projected image was the reprojected to Geographic coordinates using BlueMarble's Geographic Transformer software. Transform parameters used a resolution of 1m/pixel and a central latitude of 36N.BlueMarble Geographic Transformer 4.4
Raster
Pixel
3308
6468
0.0000110.00000981Upper LeftTRUEPackBits1pixel codesFALSETIFFdecimal degreesdecimal degrees
D_WGS_1984
WGS_1984
6378137.000000
298.257224
GCS_WGS_1984Decimal degrees0.0000090.000011row and column0.0000110.000009
David C. TwichellU.S. Geological SurveyOceanographermailing and physical address384 Woods Hole Rd.Woods HoleMA02543-1598(508) 548-8700 x2266(508) 457-2310dtwichell@usgs.gov
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 publication 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.
3.9443.944Downloadable Data
20031006
VeeAnn A. CrossU.S. Geological SurveyMarine Geologistmailing and physical address384 Woods Hole Rd.Woods HoleMA02543-1598(508) 548-8700 x2251(508) 457-2310vatnipp@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
enlocal timehttp://www.esri.com/metadata/esriprof80.htmlESRI Metadata Profile
2002111917014400FALSE20031006101349002003100610134900{39C9923B-6147-4E7D-B5FB-7FBBCC9A4139}Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 4; ESRI ArcCatalog 8.2.0.700lvwash_eng.tif-114.877684-114.80562236.13966236.1098431-114.877684-114.80562236.13966236.1098431ISO 19115 Geographic Information - MetadataDIS_ESRI1.0dataset002file://\\REDHOOK\LMofr\data\sscanimgs\geographic\enhanced\lvwash_eng.tifLocal Area Network3.944Raster DatasetGCS_WGS_1984264680.00001133080.000009120031006The pixel value represents the DN return value of the sidescan-sonar system. A high value (ie 254) indicates a highly reflective lake floor surface, while a low value (ie 0) indicates low reflectance.Band_1Table256ObjectIDObjectIDOID400Internal feature number.ESRISequential unique whole numbers that are automatically generated.ValueValueInteger000RedRedDouble000GreenGreenDouble000BlueBlueDouble000