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Photo by Lower Platte South Natural Resources District
Near Firth, Neb.
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Photo by Don Ogle, South Platte Natural Resources District
Near Sidney
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It's more precise than old-fashioned dousing. University of Nebraska-Lincoln geologists are analyzing data collected by helicopter-mounted equipment to locate underground water. Resource districts will be able to use the analyses for exploration, development and protection of groundwater supplies, said Jesse Korus, groundwater resources coordinator for the Conservation Survey Division of UNL's School of Natural Resources. The helicopter flew overhead in eastern Nebraska the week of April 20 with a large, missile-shaped object hanging beneath it. The helicopter’s electromagnetic surveys are collecting data about Nebraska's aquifers, Korus said. A similar operation was underway near Sidney in western Nebraska. Interpreting the data requires direct sampling of materials from test holes and a team of geologists. Equipment towed about 100 feet below the helicopter maps geologic structures beneath the earth. The helicopter company, Fugro Airborne Surveys, of Ontario, Canada, works with pilots who are specially trained for low-level flying. The surveys can tell what types of soils and materials exist under the surface, Korus said. "The red is materials like sand and gravel, from which groundwater can be pumped in large quantities, if it's saturated with water. The blue are materials in which groundwater doesn't flow readily, like clay or silt." Korus used visualization software to produce a three-dimensional image that combines survey data with test-hole data for an area near Firth. This image is a preliminary version of a much more comprehensive analysis that will include maps, cross sections and images. The most recent helicopter flights gathered data over study sites near Hickman, Sprague and Hallam in Lancaster County and Wahoo, Weston, Ithaca and Swedeburg in Saunders County. These studies build upon earlier HEM surveys conducted in 2007 near Firth, Ashland and Oakland. Collaborators include the U.S. Geological Survey, the Lower Platte North and Lower Platte South Natural Resources Districts, the School of Natural Resources and the Nebraska Environmental Trust. In a separate but similar survey, a helicopter carried scientific equipment about 100 feet below the helicopter in a ’spider web’ array. That chopper flew over an area about 20 x 7 miles in size directly north of Sidney, covering parts of Cheyenne and Morrill counties, according to Don Ogle of the South Platte Natural Resource District. That helicopter was operated by Geotech Ltd., Aurora, Ontario, Canada.
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