Lyndsay B. Ball 2006 vector digital data Scientific Investigations Report 2006-5032 Lincoln, Nebraska U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?sir20065032_averhoCC The U.S. Geological Survey, in cooperation with the North Platte Natural Resources District, used two surface geophysical techniques, capacitively coupled and direct-current continuous resistivity profiling, to map near-surface lithologies beneath the Interstate and Tri-State Canals in the spring and summer of 2004. This coverage represents the average electrical resistivity of sediments within the upper 8 meters below selected parts of the Interstate and Tri-State Canals within Sioux and Scotts Bluff Counties in western Nebraska and Goshen County in eastern Wyoming. These data were developed as an interpretation of the change in canal leakage potential based on the change in electrical resistivity of the upper 8-m of sediments below the beds of the Interstate and Tri-State Canals. Capacitively coupled and direct-current resistivity data were collected, processed, interpreted, and georeferenced to create a three-dimensional database for each method. Inverted resistivity sections near test holes were compared to test hole lithology, and a unique interpretive color scale was developed for each resistivity method. This scale was then applied to resistivity data between test holes, creating a uniform interpretation for the entire study area. A mathematical average of resistivity for each geographic location where data exist was made, which resulted in a single resistivity value to represent that location. The interpretive color scale related the vertically averaged resistivity data to lithologic logs. The color scale, based on the lithologic information, was determined to consistently interpret canal leakage potential. The color scale, sir20065032_averhoCC.avl, should be applied when using these data. Capacitively coupled resistivity data were used to represent the Interstate Canal and the majority of the Tri-State Canal. Direct-current resistivity data were used to represent the parts of the Tri-State Canal that were flooded during the non-irrigation season. These data are distributed as sir20065032_averhoDC.e00. Spring 2004 data collection date Complete None planned -103.890836 -103.770125 41.978149 41.928235 NONE inlandWaters, resistivity, canal leakage, geophysics NONE Nebraska, Wyoming, North Platte Natural Resources District NONE This shapefile represents interpretive data. The U.S. Geological Survey is not responsible for any outcome resulting from the use of these data. This data set should not be used at a scale of less than 1:24,000. Nebraska Water Science Center Director U.S. Geological Survey mailing address

5231 S. 19th St.

Lincoln Nebraska 68512 USA 1-888-275-8747 402-328-4101 dc_ne@usgs.gov 8 am to 4:30 pm CST Mon. thru Fri. Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.1.0.722 Ball, L.B., Kress, W.H., Steele, G.V., Cannia, J.C., Andersen, M.J. 2006 Scientific Investigations Report 2006-5032 Reston, Virginia U.S. Geological Survey Ball, Lyndsay B. 2006 vector digital vector data sir20065032_averhoDC Lincoln, Nebraska U.S. Geological Survey NONE Unknown The data set has a positional accuracy of 25 meters NONE Capacitively coupled resistivity data were collected over about 110 km of the Interstate and Tri-State Canals during 6 days in late April 2004 prior to the start of the irrigation season. The capacitively coupled resistivity survey was performed with the Geometrics OhmMapper TR-5 with one transmitter and five receivers. The TR-5 was towed across the bed of the center of both canals with an all-terrain vehicle. Data were collected using a dipole-dipole array, with a 10-meter dipole length and an initial transmitter-receiver separation distance of 2.5 meters. A differentially corrected global positioning system (GPS) was used to collect geospatial data during the resistivity survey. Geometrics, Inc's Magmap2000 version 4.56 was used for initial processing, and data were then exported for further processing and inversion using Geotomo Software's RES2DINV version 3.54w. A procedure was developed to convert the individual, local coordinate systems of the inverted resistivity sections to georeferenced coordinates on a section-by-section basis. The original GPS-derived latitude and longitude coordinates were compiled into a line, and that line was divided into the same number of points as there were model cells in the final inverted resistivity model section. Latitude and longitude coordinates were then converted to projected Universal Transverse Mercator coordinates and were joined to the inverted resistivity value and depth from the corresponding model cell. Once georeferenced, the arithmetic average was taken of the inverted resistivity values for the vertical column of model cells corresponding to each geographic coordinate. An interpretive color scale representing changes in grain size, developed using the lithologic data from test holes, was applied to the average resistivity and used to represent the relative canal leakage potential. 2005 Vector Entity point 38477 Point 4 Universal Transverse Mercator 13 0.999600 -105.000000 0.000000 500000.000000 0.000000 coordinate pair 0.000016 0.000016 meters North American Datum of 1983 Geodetic Reference System 80 6378137.000000 298.257222 NONE averhocc.pat FID Internal feature number. Shape Feature geometry. EASTING_M Easting coordinate, in meters NORTHING_M Northing coordinate, in meters AVE_RESISTIVITY Average resistivity, in ohm-meters CANAL Canal name U.S. Geological Survey Ask USGS -- Water Webserver Team mailing address

445 National Center

Reston VA 20192 USA 1-888-275-8747 (1-888-ASK-USGS) http://water.usgs.gov/user_feedback_form.html Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of these data, software, or related materials. The use of firm, trade, or brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. The names mentioned in this document may be trademarks or registered trademarks of their respective trademark owners. Export point data Winzip 799 kb http://water.usgs.gov/GIS/dsdl/sir20065032_averhocc.e00.zip None. This dataset is provided by USGS as a public service. 20060321 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing address

445 National Center

Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://water.usgs.gov/user_feedback_form.html FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998