This data set contains two sets of water-level contours that represent interpreted water-levels for an area between the Platte and Elkhorn Rivers upstream of their confluence. The contours are informed by surface-water and groundwater-level data collected during a synoptic water-level survey completed during a low-groundwater demand period in fall of 2016 and a synoptic water-level survey completed during a high-groundwater demand period in summer of 2017. Additional data and interpretations of this dataset (published in SIR XXXX) and the data included in this Data Release are intended to inform water managers of the effect of groundwater demand and flow conditions on groundwater movement and interaction with surface-water for the area near and immediately upstream from the confluence of the lower Platte and Elkhorn Rivers.

This data set contains two sets of measured water-level data collected in an area between the Platte and Elkhorn Rivers just above their confluence. Surface-water and groundwater-level data were collected for two synoptic water-level surveys during a low-groundwater demand period in fall of 2016 and a high groundwater demand period in summer of 2017. Elevations of surface-water features were surveyed with a Global Navigations Satellite System rover receiver using a real-time network, where the rover receiver receives real-time position corrections from a central server through a mobile wireless fidelity (Wi-Fi) hotspot linked to the rover receiver. Data collection procedures ensured that positions and elevations achieved USGS Level-IV survey accuracy and surveyed surface-water elevations were generally within 0.25 ft. Groundwater level data were collected from wells screened in the Quaternary-age alluvial aquifer. Prior to the groundwater-level data collection, the elevation of the selected wells was surveyed using a single base real-time kinematic (RTK) approach to achieve Level-II survey accuracy. The vertical accuracy generally was within 0.15 ft for each observation well. During synoptic water-level and streamflow surveys, groundwater-level measurements were furnished by Papio-Missouri River Natural Resources District (NRD) and Lower Platte North NRD staff or by transducers in Omaha Municipal Utilities District (MUD) recorder wells. Groundwater elevations used from recorder wells were calculated from the daily-median groundwater level from hourly recorded measurements. Additional data and interpretations of this dataset (published in SIR XXXX) and the data included in this Data Release are intended to inform water managers of the effect of groundwater demand and flow conditions on groundwater movement and interaction with surface-water for the area near and immediately upstream from the confluence of the lower Platte and Elkhorn Rivers.

This data set contains two sets of measured water-level data collected in an area between the Platte and Elkhorn Rivers just above their confluence. Surface-water and groundwater-level data were collected for two synoptic water-level surveys during a low-groundwater demand period in fall of 2016 and a high groundwater demand period in summer of 2017. Elevations of surface-water features were surveyed with a Global Navigations Satellite System rover receiver using a real-time network, where the rover receiver receives real-time position corrections from a central server through a mobile wireless fidelity (Wi-Fi) hotspot linked to the rover receiver. Data collection procedures ensured that positions and elevations achieved USGS Level-IV survey accuracy and surveyed surface-water elevations were generally within 0.25 ft. Groundwater level data were collected from wells screened in the Quaternary-age alluvial aquifer. Prior to the groundwater-level data collection, the elevation of the selected wells was surveyed using a single base real-time kinematic (RTK) approach to achieve Level-II survey accuracy. The vertical accuracy generally was within 0.15 ft for each observation well. During synoptic water-level and streamflow surveys, groundwater-level measurements were furnished by Papio-Missouri River Natural Resources District (NRD) and Lower Platte North NRD staff or by transducers in Omaha Municipal Utilities District (MUD) recorder wells. Groundwater elevations used from recorder wells were calculated from the daily-median groundwater level from hourly recorded measurements. Additional data and interpretations of this dataset (published in SIR XXXX) and the data included in this Data Release are intended to inform water managers of the effect of groundwater demand and flow conditions on groundwater movement and interaction with surface-water for the area near and immediately upstream from the confluence of the lower Platte and Elkhorn Rivers.

This data set contains 2,611 water levels collected by Natural Resources Districts in Central Nebraska. These water levels were collected by the districts to monitor groundwater levels within the districts. The water levels were provided to the USGS for use as calibration targets to the Elkhorn and Loup River Basin - Phase Three groundwater flow model. The water levels have not been previously published. This record serves as the publication record of the water levels in support of the Elkhorn and Loup River Basin - Phase Three groundwater flow model report.

This data set contains 2,611 water levels collected by Natural Resources Districts in Central Nebraska. These water levels were collected by the districts to monitor groundwater levels within the districts. The water levels were provided to the USGS for use as calibration targets to the Elkhorn and Loup River Basin - Phase Three groundwater flow model. The water levels have not been previously published. This record serves as the publication record of the water levels in support of the Elkhorn and Loup River Basin - Phase Three groundwater flow model report.

This point data set contains streamflow-measurement sites in the Elkhorn and Loup River basins and selected streamflow-measurement sites in the Niobrara and Platte River basins in north-central Nebraska. At these 531 sites, flows ranging from no flow to 2,600 cubic feet per second were measured or observed during November 8 to 21, 2006. Measurements were made by several different methods, including current meters, flumes, and acoustic Doppler velocimeters. Each measurement site location was recorded using a handheld global positioning system (GPS) unit and then downloaded and stored in a computer spreadsheet. Stored coordinates were used to produce point features in GIS native format.

This point data set contains streamflow-measurement sites in the Elkhorn and Loup River basins and selected streamflow-measurement sites in the Niobrara and Platte River basins in north-central Nebraska. At these 531 sites, flows ranging from no flow to 2,600 cubic feet per second were measured or observed during November 8 to 21, 2006. Measurements were made by several different methods, including current meters, flumes, and acoustic Doppler velocimeters. Each measurement site location was recorded using a handheld global positioning system (GPS) unit and then downloaded and stored in a computer spreadsheet. Stored coordinates were used to produce point features in GIS native format.

This data set is a georeferenced mosaic of high-resolution, aerial thermal infrared (TIR) images of the lower Elkhorn River, Nebraska, presented as a gridded (raster) image in GeoTiff format. The image is a 1.64-ft by 1.64-ft grid of corrected surface temperatures, in degrees Fahrenheit, of the lower Elkhorn River and adjacent area. The dataset encompasses a 10-mile reach of the river, from 0.4 miles upstream from USGS streamflow-gaging station 06800500, Elkhorn River at Waterloo, Nebraska, to 1.8 miles downstream from USGS site 06800800, Elkhorn River at Q St Bridge near Venice, Nebraska. This imagery was created December 15, 2017, by Cornerstone Mapping, Inc., using a FLIR SC8303 midwave thermal infrared camera mounted to a fixed-wing aircraft.

This data set is a georeferenced mosaic of high-resolution, aerial thermal infrared (TIR) images of the lower Elkhorn River, Nebraska, presented as a gridded (raster) image in GeoTiff format. The image is a 1.64-ft by 1.64-ft grid of corrected surface temperatures, in degrees Fahrenheit, of the lower Elkhorn River and adjacent area. The dataset encompasses a 10-mile reach of the river, from 0.4 miles upstream from USGS streamflow-gaging station 06800500, Elkhorn River at Waterloo, Nebraska, to 1.8 miles downstream from USGS site 06800800, Elkhorn River at Q St Bridge near Venice, Nebraska. This imagery was created December 15, 2017, by Cornerstone Mapping, Inc., using a FLIR SC8303 midwave thermal infrared camera mounted to a fixed-wing aircraft.

The U.S. Geological Survey (USGS) refined the spatial and temporal discretization of a previously modeled area (Phase 1: https://pubs.usgs.gov/sir/2008/5143/ and Phase 2: https://pubs.usgs.gov/sir/2010/5149/) which focused on a 30,000-square-mile area of the High Plains aquifer. Regional groundwater-flow models were constructed to evaluate the effects of groundwater withdrawal on stream base flow in the Elkhorn and Loup River Basins, Nebraska. The model was calibrated to match groundwater level and base-flow data from the stream-aquifer system during the pre-1940 through 2010 period (including predevelopment [pre-1895], early development [1895–1940], and historical development [1940 through 2010] conditions) using an automated parameter- estimation method. The calibrated model was then used to simulate hypothetical development conditions (2011 through 2060). To assess the impact of wells on aquifer depletions, additional wells were simulated throughout the model domain and pumped for 50 years. The percentage of each well’s withdrawal after 50 years, which was compensated by aquifer reductions to stream base flow, storage, or evapotranspiration, was computed and mapped. This data release also includes the MODFLOW-NWT (version 1.0.7) source code. This USGS data release contains all of the input and output files for the model described in the associated model documentation report (https://doi.org/10.3133/sir20185106).