OF 2004-1247 HOME

Disc Contents

Introduction

Data/GIS

Metadata/Data Catalog

References Cited

Contacts

Introduction:

Lake Mohave is one of several multi-purpose reservoirs that have been constructed on the Colorado River. The lake was formed upon completion of the Davis Dam in 1953. Since then, research on this reservoir has dealt primarily with vegetation surrounding the lake (Tallent-Halsell and Walker, 2002), fish (Bozek et al., 1990), water quality (Paulson and Baker, 1983), and geological hazards to recreation areas surrounding the lake associated with flash floods (Glancy and Harmsen, 1975; Moosburner, 1979; 1981). No mapping of the floor of the lake had been conducted since completion of the Davis Dam. Because of the lack of lake-floor maps, the U.S. Geological Survey in cooperation with researchers from the University of Nevada Las Vegas completed a geophysical survey of this lake in April 2002. The survey included collection of sidescan-sonar imagery of nearly the entire lake floor. Over 362 km of sidescan imagery was collected with a DF1000 towfish operating at a frequency of 100 kHz. Swath widths of 150 to 600 m were used to maximize lake floor coverage. What follows is a series of images showing the sidescan-sonar coverage of the lake working from north to south. Clicking on any image will open a larger image of the same area.

In addition to the sidescan-sonar imagery, high-resolution seismic-reflection profiles were collected along widely spaced lines throughout the lake. Over 410 km of data were acquired with a Knudsen chirp subbottom system operating at a central frequency of 3.5 kHz. What follows is a series of images indicating the tracklines along which seismic-reflection data were collected. The images progress from north to south. Clicking on any image will open a larger image of the same area.

The detailed mapping of the lake floor was used to determine the amount of sediment that had accumulated in the lake since impoundment, its distribution, and the processes of deposition.

This report presents the data and GIS used as the foundation for the report by Foster and others (2004). These data include the georeferenced sidescan-sonar mosaic, raw navigation, processed navigation for both seismic and sidescan tracklines, JPEG images of the seismic-reflection profiles, and the polygon shapefile of the interpretation resulting from the analysis of these data. Brief descriptions of these data types can be found in the Data/GIS section of this report, while the accompanying FGDC compliant metadata, as well as links to the data, can be found in the Metdata/Data Catalog section of this report.