Enhanced TIFF Sicescan-Sonar Mosaic East of Virgin Basin - Lake Mead, Nevada: UTM Projection

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Metadata:
Identification_Information:
Citation:
Citation_Information:
Originator: David C. Twichell
Originator: VeeAnn A. Cross
Publication_Date: 2003
Title:
Enhanced TIFF Sicescan-Sonar Mosaic East of Virgin Basin - Lake Mead, Nevada: UTM Projection
Geospatial_Data_Presentation_Form: remote-sensing image
Online_Linkage:
Larger_Work_Citation:
Citation_Information:
Originator: David C. Twichell
Originator: VeeAnn A. Cross
Originator: Stephen D. Belew
Publication_Date: 2003
Title:
Mapping the floor of Lake Mead (Nevada and Arizona): Preliminary discussion and GIS data release
Edition: 1.0
Series_Information:
Series_Name: Open-File Report
Issue_Identification: 03-320
Publication_Information:
Publication_Place: Woods Hole Field Center, Woods Hole, MA
Publisher: U.S. Geological Survey
Description:
Abstract:
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.
Purpose:
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.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20010401
Ending_Date: 20010426
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -114.368843
East_Bounding_Coordinate: -114.023191
North_Bounding_Coordinate: 36.205417
South_Bounding_Coordinate: 36.003032
Keywords:
Theme:
Theme_Keyword_Thesaurus: General
Theme_Keyword: CMGP
Theme_Keyword: Coastal and Marine Geology Program
Theme_Keyword: images
Theme_Keyword: lake
Theme_Keyword: mosaic
Theme_Keyword: OFR03-320
Theme_Keyword: Open-File Report
Theme_Keyword: reservoir
Theme_Keyword: sidescan
Theme_Keyword: sidescan sonar
Theme_Keyword: TIFF
Theme_Keyword: U.S. Geological Survey
Theme_Keyword: USGS
Theme_Keyword: Woods Hole Field Center
Place:
Place_Keyword_Thesaurus: General
Place_Keyword: Lake Mead
Place_Keyword: Nevada
Place_Keyword: United States
Place_Keyword: Las Vegas
Place_Keyword: Hoover Dam
Place_Keyword: Colorado River
Place_Keyword: Mojave Desert
Place_Keyword: Grand Canyon
Place_Keyword: Black Canyon
Place_Keyword: Arizona
Place_Keyword: North America
Access_Constraints: NONE
Use_Constraints:
The U.S. Geological Survey must be referenced as the originator of the dataset in any future products or research derived from these data.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: David C. Twichell
Contact_Organization: U.S. Geological Survey
Contact_Position: Oceanographer
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700 x2266
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: dtwichell@usgs.gov
Native_Data_Set_Environment:
Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 4; ESRI ArcCatalog 8.2.0.700
Cross_Reference:
Citation_Information:
Originator: H.E. Bevans
Originator: S.L. Goodbred
Originator: J.F. Miesner
Originator: S.A. Watkins
Originator: T.S. Gross
Originator: N.D. Denslow
Originator: T. Choeb
Publication_Date: 1996
Title:
Synthetic organic compounds and carp endrocrinology and histology, Las Vegas Wash and Las Vegas and Callville bays of Lake Mead Nevada
Series_Information:
Series_Name: Water-Resources Investigations
Issue_Identification: 96-4266
Publication_Information:
Publisher: U.S. Geological Survey
Cross_Reference:
Citation_Information:
Originator: H.E. Bevans
Originator: M.S. Lico
Originator: S.J. Lawrence
Publication_Date: 1998
Title:
Water quality in the Las Vegas Valley area and the Carson and Truckee River basins, Nevada and California, 1992-1996
Series_Information:
Series_Name: Circular
Issue_Identification: 1170
Publication_Information:
Publisher: U.S. Geological Survey
Cross_Reference:
Citation_Information:
Originator: K.J. Couvay
Originator: T.J. Leiker
Publication_Date: 1998
Title:
Synthetic organic compounds in water and bottom sediment from streams, detention basins, and sewage-treatment plant outfalls in Las Vegas Valley, Nevada, 1997
Series_Information:
Series_Name: Open-File Report
Issue_Identification: 98-633
Publication_Information:
Publisher: U.S. Geological Survey
Cross_Reference:
Citation_Information:
Originator: H.R. Gould
Publication_Date: 1951
Title: Some quantitative aspects of Lake Mead turbidity currents
Series_Information:
Series_Name: SEPM Special Publication
Issue_Identification: No. 2
Publication_Information:
Publisher: Society of Economic Paleontologists and Mineralogists
Cross_Reference:
Citation_Information:
Originator: J.F. LaBounty
Originator: M.J. Horn
Publication_Date: 1997
Title:
The influence of drainage from the Las Vegas Valley on the limnology of Boulder Basin, Lake Mead, Arizona-Nevada
Series_Information:
Series_Name: Journal of Lake and Reservoir Management
Issue_Identification: v. 13
Cross_Reference:
Citation_Information:
Originator: L.J. Paulson
Publication_Date: 1981
Title:
Nutrient management with hydroelectric dams on the Colorado River
Series_Information:
Series_Name: Technical Report
Issue_Identification: #8
Publication_Information:
Publication_Place:
Department of Biological Sciences, University of Nevada, Las Vegas, Nevada
Publisher: Lake Mead Limnological Research Center
Cross_Reference:
Citation_Information:
Originator: A.M. Preissler
Originator: G.A. Roach
Originator: K.A. Thomas
Originator: J.W. Wilson
Publication_Date: 1998
Title: Water resources data, Nevada, water year 1998
Series_Information:
Series_Name: Water Resources Data Nevada
Issue_Identification: NV-98-1
Publication_Information:
Publisher: U.S. Geological Survey
Data_Quality_Information:
Logical_Consistency_Report:
All these data were collected with the same sidescan-sonar towfish. The majority of the data comprising this mosaic was acquired at a 1500m total swath width. In some small areas, data gaps were filled with data collected at a 750m total swath width. However, in each case, the data were resampled to a 2 m pixel size.
Completeness_Report: All imagery necessary to map the lake floor was used.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
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. Therefore range to fish values are assumed consistent and accurate.
Lineage:
Process_Step:
Process_Description:
Sidescan sonar imagery was collected using a Datasonics SIS-1000 sidescan sonar system and logged to a Triton QMIPS data logging computer.
Process_Step:
Process_Description:
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 attenuation, and dropped sonar lines using XSonar (Danforth et al., 1991). After these processing steps, 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 2 m/pixel. Due to the difficult nature of working in a lake environment, XSonar was modified by Danforth to incorporate the ability to exclude portions of the imagery from the beam angle correction routine. This enabled the stark contrast between highly reflection rock outcrops and fine-grained sediment deposits to be preserved. This enhancement was not available in 2001 when the data were collected, so the data were reprocessed in 2001. Processing the data up to this point was done be VeeAnn Cross.
Source_Used_Citation_Abbreviation:
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.
Source_Used_Citation_Abbreviation:
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.
Process_Step:
Process_Description:
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). Processing of the data from this point on was done by David C. Twichell.
Source_Used_Citation_Abbreviation:
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.
Process_Step:
Process_Description:
Because of the close relationship of the imagery to the topography of the lake, a shaded-relief image generated from the DEM with the 10m contours burned into it was imported to PCI and the sidescan-sonar image strips were georeferenced to it. Misalignments based on the ground control points that were selected between the sidescan-sonar imagery and the DEM after georeferencing were less than 20m in all areas of the lake except a small section of Black Canyon and part of Boulder Canyon.
Process_Step:
Process_Description:
The mosaic then had a linear stretch applied to the data to reduce the valid data range from 0-255 to 0-254. When mapped on a white background, the background can be made transparent in the GIS without affecting the data.
Process_Step:
Process_Description:
Once the mosaics were completed, noise and areas of no data were trimmed from the fringes of the completed mosaic. The lake shoreline as defined by the U.S. Bureau of Reclamation was used to trim noise and nodata areas that fell beyond the limits of the lake.
Process_Step:
Process_Description:
A root stretch was applied in PCI to the sidescan image to help enhance the features. The root stretch was from 15-220 with resulting values between 0 and 254. This was done so that the white background (255) could be made transparent in the GIS.
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Pixel
Row_Count: 10797
Column_Count: 15263
Vertical_Count: 1
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name: Universal Transverse Mercator
Universal_Transverse_Mercator:
UTM_Zone_Number: 11
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: 0.999600
Longitude_of_Central_Meridian: -117.000000
Latitude_of_Projection_Origin: 0.000000
False_Easting: 500000.000000
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: row and column
Coordinate_Representation:
Abscissa_Resolution: 2.000000
Ordinate_Resolution: 2.000000
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: D_WGS_1984
Ellipsoid_Name: WGS_1984
Semi-major_Axis: 6378137.000000
Denominator_of_Flattening_Ratio: 298.257224
Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
The 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.
Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: David C. Twichell
Contact_Organization: U.S. Geological Survey
Contact_Position: Oceanographer
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700 x2266
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: dtwichell@usgs.gov
Resource_Description: Downloadable Data
Distribution_Liability:
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.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Transfer_Size: 20.266
Metadata_Reference_Information:
Metadata_Date: 20031006
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: VeeAnn A. Cross
Contact_Organization: U.S. Geological Survey
Contact_Position: Marine Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700 x2251
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: vatnipp@usgs.gov
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
Metadata_Extensions:
Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>
Profile_Name: ESRI Metadata Profile
Generated by mp version 2.7.3 on Mon Oct 06 12:24:50 2003