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.