Identification_Information: Citation: Citation_Information: Originator: David C. Twichell Originator: VeeAnn A. Cross Publication_Date: 2003 Title: Sidescan-sonar Tracklines in the Geographic Coordinate System - Lake Mead 2000 Geospatial_Data_Presentation_Form: vector digital data 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: A 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. Purpose: This ArcView shapefile defines the tracklines along which sidescan sonar data was collected. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20000601 Ending_Date: 20000606 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -114.874450 East_Bounding_Coordinate: -114.808870 North_Bounding_Coordinate: 36.135890 South_Bounding_Coordinate: 36.114000 Keywords: Theme: Theme_Keyword_Thesaurus: General Theme_Keyword: sidescan sonar Theme_Keyword: trackline Theme_Keyword: navigation Theme_Keyword: reservoir Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: Open-File Report Theme_Keyword: OFR03-320 Theme_Keyword: cruise serial number 00027 Place: Place_Keyword_Thesaurus: General Place_Keyword: Las Vegas Place_Keyword: Lake Mead Place_Keyword: Nevada Place_Keyword: Las Vegas Bay Place_Keyword: Las Vegas Wash Place_Keyword: Boulder Basin Place_Keyword: United States 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 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: V.A. Cross Originator: D.C. Twichell Publication_Date: 2003 Title: Archive of Seismic-Reflection Data Collected During USGS Cruise Lake Mead 00027 in Lake Mead - Nevada, 1-6 June, 2000 Series_Information: Series_Name: Open-File Report Issue_Identification: 03-004 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: These lines represent the lines along which sidescan-sonar image data were collected. Completeness_Report: Complete. Positional_Accuracy: Horizontal_Positional_Accuracy: Quantitative_Horizontal_Positional_Accuracy_Assessment: Horizontal_Positional_Accuracy_Value: 10-20m Horizontal_Positional_Accuracy_Explanation: The 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. Lineage: Process_Step: Process_Description: 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. Process_Step: Process_Description: 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. Process_Step: Process_Description: 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. Process_Step: Process_Description: Within ArcView, additional attribute information for each line was added. Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: String Point_and_Vector_Object_Count: 26 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.000000 Longitude_Resolution: 0.000000 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257222 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: ssnav_00.dbf Entity_Type_Definition: ArcView shapefile attribute table Entity_Type_Definition_Source: ESRI Attribute: Attribute_Label: FID Attribute_Definition: Internal feature number. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated. Attribute: Attribute_Label: Shape Attribute_Definition: Feature geometry. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Coordinates defining the features. Attribute: Attribute_Label: LINENUM Attribute_Definition: A 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. Attribute_Definition_Source: VeeAnn A. Cross Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 503 Attribute: Attribute_Label: FILENAME Attribute_Definition: Prefix of the filename assigned to each line of sidescan-sonar data collected. Attribute_Definition_Source: Kenneth F. Parolski Attribute_Domain_Values: Unrepresentable_Domain: Character data set Attribute: Attribute_Label: SWATH Attribute_Definition: The total swath that the sidescan-sonar imagery covers (in meters). Attribute_Definition_Source: VeeAnn A. Cross Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: 200m Enumerated_Domain_Value_Definition: 200 meters Attribute: Attribute_Label: lengthm Attribute_Definition: The length of each line segment in meters. Attribute_Definition_Source: Software computed. Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 529 Range_Domain_Maximum: 2243 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 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: 0.028 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: REQUIRED: The mailing and/or physical address for the organization or individual. City: REQUIRED: The city of the address. State_or_Province: REQUIRED: The state or province of the address. Postal_Code: REQUIRED: The ZIP or other postal code of the address. 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