Groundwater Flooding on Highways in the Nebraska Sandhills: Applying Remote Sensing, Precipitation and Groundwater Modeling to Determine Depth, Cause and Frequency

Authors

Aaron R. Mittelstet, University of Nebraska-LincolnFollow

Date of this Version

7-1-2025

Document Type

Article

Citation

Mittelstet, A. (2025). "Groundwater Flooding on Highways in the Nebraska Sandhills: Applying Remote Sensing, Precipitation and Groundwater Modeling to Determine Depth, Cause and Frequency", NDOT Research Report SPR-FY22(005).

Abstract

Climate change significantly impacts infrastructure sustainability, particularly through shifts in precipitation patterns, intensity, and duration. These precipitation dynamics may increase the occurrence of surface water and groundwater flooding. Groundwater in the Nebraska Sand Hills (NSH), including the thickest portions of the High Plains Aquifer, extends close to the land surface in interdunal areas, making the NSH vulnerable to groundwater flooding. Recent events involving heavy precipitation, snow melt, and rising groundwater levels have caused prolonged highway flooding, disrupting transportation networks. This study estimates groundwater flood inundation depth, duration and frequency in the highways of NSH using remote sensing techniques and groundwater modeling. Results indicate that in 2019, 18 highway sections experienced inundation depths ranging from 0.04 to 0.63 m for up to five months. This flooding was not caused by a single storm event but resulted from cumulative precipitation in 2018 and 2019. Using MODFLOW, we analyzed historical flooding (> 1 m increase in water level over a one- and two-year period) from 1940 to 2009 for ten highways within the NSH and model domain. Flooding frequencies ranged from 0% to 2.7% and from 1.4% to 11% for the two-year periods. These findings provide critical insights for the Nebraska Department of Transportation to prioritize highway improvement efforts in mitigating future flood risks through future construction projects to raise these highways. Observed trends in increasing precipitation, stream discharge and groundwater levels over recent decades, and their role in contributing to major flood events in 2010 and 2019, flooding risks may escalate in the future.