{E921F5DB-233F-47B1-AF8A-138AD498C9D1}2001100218131700FALSE20031006113915002003100611391500Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 4; ESRI ArcCatalog 8.2.0.700enA one-week geophysical survey was conducted in the Las Vegas Bay part of Lake Mead during June 1-6, 2000 to acoustically map the surficial sediments and shallow subsurface geology of this part of the lake. The study was done by researchers from the U.S. Geological Survey, Coastal and Marine Geology Program in Woods Hole, MA and the University of Nevada at Las Vegas. The objective was to map the distribution, volume and acoustic character of sediment that has accumulated on the floor of this part of the lake. The need for systematic mapping of this part of the lake's floor is because pollutants associated with surface and groundwater enter the lake through Las Vegas Wash at the head of Las Vegas Bay. Some of the pollutants transported to the lake by this runoff are deposited with the sediments on the lake floor. Understanding the distribution of sediments in the lake is needed to establish an effective monitoring program. The study built upon a geophysical survey conducted by the USGS and UNLV in 1999 that covered the deeper water parts of Las Vegas Bay and Boulder Basin. This year's survey focussed on the shallow water parts of the head of Las Vegas Bay with particular attention being directed at Las Vegas, Gypsum and Government Washes. Of these three Washes, the most effort was put into surveying Las Vegas Wash. This survey was conducted with an Edgetech DF-1000 sidescan sonar, a Knudsen high-resolution chirp subbottom profiling system, a Garmin fathometer, and P-Code GPS navigation. All data were logged digitally.This ArcView shapefile defines the tracklines along which sidescan sonar data was collected.David C. Twichell2003ssnav_00vector digital dataVeeAnn A. CrossDavid C. TwichellVeeAnn A. CrossStephen D. Belew2003Open-File Report03-320U.S. Geological SurveyWoods Hole Field Center, Woods Hole, MA1.0 ground condition2000060120000606CompleteNone planned-114.874450-114.80887036.13589036.114000-114.874450-114.80887036.11400036.135890sidescan sonartracklinenavigationreservoirGeneralU.S. Geological SurveyUSGSCoastal and Marine Geology ProgramCMGPOpen-File ReportOFR03-320cruise serial number 00027Las VegasLake MeadNevadaLas Vegas BayLas Vegas WashGeneralBoulder BasinUnited StatesNorth AmericanoneThe U.S. Geological Survey must be referenced as the originator of the dataset in any future products or research derived from these data. ShapefileDavid C. TwichellU.S. Geological SurveyOceanographermailing and physical address

384 Woods Hole Rd.

Woods HoleMA02543508-548-8700 x2266508-457-2310dtwichell@usgs.govH.E. BevansS.L. GoodbredJ.F. MiesnerS.A. WatkinsT.S. GrossN.D. DenslowT. Choeb1996Water-Resources Investigations96-4266U.S. Geological SurveyH.E. BevansM.S. LicoS.J. Lawrence1998Circular1170U.S. Geological SurveyK.J. CouvayT.J. Leiker1998Open-File Report98-633U.S. Geological SurveyV.A. CrossD.C. Twichell2003Open-File Report03-004U.S. Geological SurveyH.R. Gould1951SEPM Special PublicationNo. 2Society of Economic Paleontologists and MineralogistsJ.F. LaBountyM.J. Horn1997Journal of Lake and Reservoir Managementv. 13L.J. Paulson1981Technical Report#8Department of Biological Sciences, University of Nevada, Las Vegas, NevadaLake Mead Limnological Research CenterA.M. PreisslerG.A. RoachK.A. ThomasJ.W. Wilson1998Water Resources Data NevadaNV-98-1U.S. Geological SurveyenFGDC Content Standards for Digital Geospatial MetadataFGDC-STD-001-1998local timeREQUIRED: The mailing and/or physical address for the organization or individual.REQUIRED: The city of the address.REQUIRED: The state or province of the address.REQUIRED: The ZIP or other postal code of the address.508-548-8700 x2251VeeAnn A. CrossU.S. Geological SurveyMarine Geologist508-457-2310vatnipp@usgs.gov20031006http://www.esri.com/metadata/esriprof80.htmlESRI Metadata ProfileVectorSimplePolylineFALSE26TRUEFALSEString26GCS_North_American_1983Decimal degrees0.0000000.000000North American Datum of 1983Geodetic Reference System 806378137.000000298.257222ssnav_00.dbfFeature Class26ArcView shapefile attribute tableESRIFIDFIDOID400Internal feature number.ESRISequential unique whole numbers that are automatically generated.ShapeShapeGeometry000Feature geometry.ESRICoordinates defining the features.LINENUMLINENUMNumber6A numeric value indicating a line number. Test files collected during the cruise and subsequently used for interpretations are given line numbers in the range of 501-503. This is to differentiate test file 1 from line 1.VeeAnn A. Cross1503FILENAMEFILENAMEString10Prefix of the filename assigned to each line of sidescan-sonar data collected.Kenneth F. ParolskiCharacter data setSWATHSWATHString8The total swath that the sidescan-sonar imagery covers (in meters).VeeAnn A. Cross200m200 meterslengthmlengthmNumber163The length of each line segment in meters.Software computed.52922430.0280.028David C. TwichellU.S. Geological SurveyOceanographermailing and physical address

384 Woods Hole Rd.

Woods HoleMA02543508-548-8700 x2266508-457-2310dtwichell@usgs.govThese 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.Downloadable DataThese lines represent the lines along which sidescan-sonar image data were collected.Complete.10-20mThe navigation data were collected with a P-CODE GPS with an assumed accurace of +/- 10 m. Additional error is encountered due to the offset between the sidescan-sonar towfish and the navigation antenna. Furthermore, the navigation was downsampled so that only the most accurate navigation positions are the vertex points of the line.Navigation was acquired by a Hypack navigation system and stored with the Edgetech sidescan sonar data on a QMIPS computer data acquisition system. A unique navigation point was sent to the acquisition system approximately every 10 seconds. Upon extracting the sidescan-sonar data from the acquisition system, the navigation was downsampled to 1 minute intervals.This 1 minute navigation was then reviewed for errors and sometimes further downsampled to enable the swath of sidescan-sonar imagery to have a smooth track.This navigation for each line of sidescan data was then combined with all the other lines into an Arc/Info ungenerate format for import into ArcView.Within ArcView, additional attribute information for each line was added.Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 4; ESRI ArcCatalog 8.2.0.700ssnav_00-114.87445-114.8088736.1358936.1141-114.87445-114.8088736.1358936.1141ISO 19115 Geographic Information - MetadataDIS_ESRI1.0dataset002file://\\REDHOOK\LMofr\data\nav\2000\ssnav_00.shpLocal Area Network0.028ShapefileGCS_North_American_19832620031006