Identification_Information: Citation: Citation_Information: Originator: Smith, Devine Publication_Date: Unknown Title: Sprague HEM flight path Geospatial_Data_Presentation_Form: vector digital data Online_Linkage: open-file-report USGS digital publication Description: Abstract: Innovative approaches to water resources data collection are evolving in response to demands for the development of accurate hydrogeologic frameworks. Helicopter electromagnetic (HEM) surveys, flown in five selected areas of eastern Nebraska in 2007 and 2009, mapped high-resistivity areas that correlate to and expand on known sand and gravel aquifers. To date, a total area of 680 km2 (263 mi2) has been surveyed using HEM. General flight line spacing was 270 m (890 ft). The primary purpose of the survey in 2007 was to test the applicability of HEM technology in identifying sand and gravel units underlying or within glacial deposits. Results from the 109 km2 (42 mi2) Firth pilot-study area indicated that expanding the study area to the west might allow better delineation of the interconnectivity of sand units with surface-water systems. Apparent resistivity maps from the Firth area showed two elongated bands of high-resistivity material that were interpreted as sand and gravel forming the shallowest portions and sides of a paleovalley aquifer. Evaluation of the depths of signal detection, which reached to 45 m (150 ft) in the deepest part of the sand and gravel unit, and the horizontal and vertical resolution were based on inverse modeling of vertical sections and resolution imaging, and not from the apparent resistivity maps. The data provide the aquifer’s general trend and areal extent, though not its full depth. At Firth, the 2009 survey extended the 2007 survey westward, but used the same flight line spacing and orientation as in 2007 and covered approximately 285 km2 (110 mi2). The 2009 survey was to delineate the western end of the paleovalley aquifer. The apparent resistivity data collected in overlapping flight blocks of the 2007 and 2009 surveys were congruent. Geologists expected the paleovalley aquifer to appear as in the first survey. However, preliminary data from the second block show highly resistive material is more widespread than in the original flight block. In addition to the paleovalley area, a separate small survey block of 78 km2 (30 mi2) was completed in the Swedeburg area. This survey is located on the western edge of the Todd Valley. The apparent resistivity maps from each survey are congruent and define areas of possible shallow and localized sand and gravel aquifers. (Citation: Devine, D.P., Steele, G.V., Smith, B.D., and Ehrman, R.L., 2009, Preliminary Results from Helicopter Electromagnetic Surveys over a Paleovalley Aquifer in Eastern Nebraska, Proceedings Geological Society of America, Annual Meeting,1p.) Purpose: The purpose of this study is to enhance understanding of the ground-water and surface-water relationships in Eastern Nebraska. This data set provides the flight path for the helicopter electromagnetic (HEM) survey near Sprague, Nebraska. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2009 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -96.415255 East_Bounding_Coordinate: -96.232461 North_Bounding_Coordinate: 41.165401 South_Bounding_Coordinate: 41.045244 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme_Keyword: imageryBaseMapsEarthCover Theme_Keyword: environment Place: Place_Keyword_Thesaurus: Geographic Names Information System Place_Keyword: Nebraska Place_Keyword: Sprague Access_Constraints: None Use_Constraints: None Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Bruce D. Smith Contact_Organization: U.S. Geological Survey Contact_Position: Geophysicist Contact_Address: Address_Type: mailing address Address: PO Box 25046,MS964 Address: Denver Federal Center City: Denver State_or_Province: CO Postal_Code: 80225 Country: USA Contact_Voice_Telephone: 303.236.1399 Contact_Electronic_Mail_Address: bsmith@usgs.gov Contact_Instructions: Contact via email Native_Data_Set_Environment: Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Arc feature attribute values were inspected and found to be consistently coded as described in the Entity and Attribute section. Logical_Consistency_Report: Using ArcGIS tools and routines all arcs were checked for node errors, overshoots, undershoots, dangles, intersections, and duplicate features. Completeness_Report: This data set includes only the study area for the HEM investigation conducted near Firth, Nebraska. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Horizontal accuracy was not assessed. Lineage: Process_Step: Process_Description: The flight path was recorded during the HEM survey and exported to an AutoCAD format *.dxf file containing the line number annotation and the lines surveyed. Process_Date: 20090715 Process_Step: Process_Description: Metadata imported. Source_Used_Citation_Abbreviation: USGS digital open-file-report Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: String Point_and_Vector_Object_Count: 33 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Transverse Mercator Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -99.000000 Latitude_of_Projection_Origin: 0.000000 False_Easting: 500000.000000 False_Northing: 0.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 1.49693125 Ordinate_Resolution: 1.49693125 Planar_Distance_Units: meters 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: Polyline Entity_Type_Definition: Flight path of HEM survey Entity_Type_Definition_Source: U.S. Geological Survey 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: Handle Attribute_Definition: Unique ID from DXF polyline Attribute_Definition_Source: U.S. Geological Survey Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: xxf Enumerated_Domain_Value_Definition: String of values and text representing the flight path line Enumerated_Domain_Value_Definition_Source: U.S. Geological Survey Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Position: Water Webserver Team Contact_Address: Address_Type: mailing address Address: 12201 Sunrise Valley Drive, MS 440 City: Reston State_or_Province: VA Postal_Code: 20192 Country: USA Contact_Voice_Telephone: 1-888-475-8747 (1-888-ASK-USGS) Contact_Instructions: Contact via email Resource_Description: Downloadable Data Distribution_Liability: 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 this data, software, or related materials. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: Shapefile Transfer_Size: 0.324 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://water.usgs.gov/GIS/ashland_HEMflight_path_nad83.zip Fees: None Metadata_Reference_Information: Metadata_Date: 20071031 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: ?? Contact_Organization: U.S. Geological Survey Contact_Position: ?? Contact_Address: Address_Type: mailing and physical address Address: 5231 S 19th Street City: Lincoln State_or_Province: NE Postal_Code: 68512 Country: USA Contact_Voice_Telephone: 402.328.4100 Contact_Electronic_Mail_Address: xxxx@usgs.gov Contact_Instructions: Contact via email 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