Shapefile of the postimpoundment sediment limits in Lake Mead

Metadata:

• Identification_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: David C. Twichell

Originator: VeeAnn A. Cross

Publication_Date: 2003

Title: Shapefile of the postimpoundment sediment limits in Lake Mead

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

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 shapefile indicates the extent of postimpoundment sediment in Lake Mead as mapped by seismic-reflection profiles and sidescan-sonar imagery.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 19990514

Ending_Date: 20010426

Currentness_Reference: ground condition

Status:

Progress: Complete

Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -114.875551

East_Bounding_Coordinate: -114.024756

North_Bounding_Coordinate: 36.485049

South_Bounding_Coordinate: 36.012384

Keywords:

Theme:

Theme_Keyword_Thesaurus: General

Theme_Keyword: ArcView

Theme_Keyword: bounds

Theme_Keyword: lake

Theme_Keyword: OFR03-320

Theme_Keyword: Open-File report

Theme_Keyword: polygon

Theme_Keyword: reservoir

Theme_Keyword: U.S. Geological Survey

Theme_Keyword: USGS

Theme_Keyword: Woods Hole Field Center

Theme_Keyword: sediment

Place:

Place_Keyword_Thesaurus: General

Place_Keyword: Arizona

Place_Keyword: Black Canyon

Place_Keyword: Boulder Basin

Place_Keyword: Colorado River

Place_Keyword: Gregg Basin

Place_Keyword: Hoover Dam

Place_Keyword: Iceberg Canyon

Place_Keyword: Lake Mead

Place_Keyword: Las Vegas

Place_Keyword: Las Vegas Bay

Place_Keyword: Las Vegas Wash

Place_Keyword: Mojave Desert

Place_Keyword: Nevada

Place_Keyword: Overton Arm

Place_Keyword: United States

Place_Keyword: Virgin Basin

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

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Vector

Point_and_Vector_Object_Information:

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: G-polygon

Point_and_Vector_Object_Count: 4

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: sedlimit

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: ID

Attribute_Definition: Internally generated number.

Attribute_Definition_Source: software generated

Attribute:

Attribute_Label: INTERP

Attribute_Definition:

Indicates that the polygon surrounds an area with post-impoundment sediment.

Attribute_Definition_Source: David C. Twichell

Attribute_Domain_Values:

Unrepresentable_Domain: character dataset

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) 548-8700x2266

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: 0.323

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