Folders: ROOT > ScienceBase Catalog > USGS Lower Mississippi-Gulf Water Science Center > @ Lake and Reservoir Studies > Geophysical surveys and geospatial data for Bob Kidd Lake, Washington County, Arkansas ( Show all descendants )
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ROOT _ScienceBase Catalog __USGS Lower Mississippi-Gulf Water Science Center ___@ Lake and Reservoir Studies ____Geophysical surveys and geospatial data for Bob Kidd Lake, Washington County, Arkansas Filters
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DC Resitivity Methodology Direct current (DC) resistivity transects were surveyed using an IRIS Syscal Pro Switch 96 instrument (IRIS Instruments, Inc., Orléans, France). Steel electrodes were hammered into the ground at a fixed distance along the profile. These were connected to the instrument using copper wires and junction boxes. The number of electrodes on each profile and their spacing is shown below: Line 1: 180 electrodes, 5 meter spacing Line 2: 48 electrodes, 2 meter spacing Line 3: 48 electrodes, 2 meter spacing Line 4: 24 electrodes, 2 meter spacing Line 5: 36 electrodes, 2 meter spacing On Line 1, the roll-along method was used to extend the line to its full extent. In this method, 48 electrodes...
Categories: Data
GNSS Method A benchmark monument was set at each end of the earthen dam in accordance with (U.S. Army Corps of Engineers, 2002). A level II survey (Rydlund & Densmore 2012) was conducted on each monument to establish control. Two 4-hour observations were conducted with a staggered approach for each monument, with one 4-hour session in the morning of the first day and one 4-hour session in the afternoon of the second day. Once elevational control was established, a Real Time Kinematic (RTK) system was set up with base on the monument that had the best observations. Using this system, a point cloud survey was conducted along the top and face of the dam using both a monopod and an All-Terrain Vehicle. A Global...
Categories: Data
FDEM Methodology For this project frequency domain electromagnetic (FDEM) data were collected with a GEM-2, a broadband, multifrequency, fixed-coil electromagnetic induction unit (Geophex, 2015). Both in-phase and quadrature data were collected on 15 channels from a frequency of 810 Hz to 66,090 Hz. This system was carried along profiles that followed the axis of the dam and along tie lines that were perpendicular to the axis of the dam. Each data point was located using a backpack mounted GPS. To correct the drift of the instrument, a base station was established on the east side of the dam. Each survey started and ended with an occupation of the base station. These occupations occur as even line numbers...
Categories: Data
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