Mahmoud et al. (2025) Groundwater recharge dynamics to recent wetting in a cold region aquifer

Identification

• Journal: Journal of Hydrology Regional Studies
• Year: 2025
• Date: 2025-11-05
• Authors: Hazem H. Mahmoud, Taufique H. Mahmood, Scott F. Korom
• DOI: 10.1016/j.ejrh.2025.102902

Research Groups

• Harold Hamm School of Geology and Geological Engineering, University of North Dakota, Grand Forks, ND 58202, United States
• College of Engineering and Mines, University of North Dakota, Grand Forks, ND 58202, United States
• Center for Water Research, University of North Dakota, Grand Forks, ND 58202, United States

Short Summary

This study quantified groundwater recharge to the Oakes aquifer in southeastern North Dakota for the 1991–2024 water years using field observations and process-based models, revealing that spring and summer rainfall is the primary recharge source, with snowmelt contributing variably based on frozen soil conditions and winter temperatures.

Objective

• To quantify the effects of physical and climatic drivers (snow distribution, precipitation patterns, land cover, lithology, topography, surface depressions) on groundwater recharge to the Oakes aquifer and evaluate how these effects vary across contrasting climate conditions.
• To explore long-term climate trends and assess corresponding trends in groundwater recharge over multiple decades.

Study Configuration

• Spatial Scale: Oakes aquifer, southeastern North Dakota, USA, covering an area of 421.9 km².
• Temporal Scale: 1991–2024 water years (34 years). Field observations were conducted during 2022–2024.

Methodology and Data

• Models used: Cold Region Hydrological Model (CRHM), HYDRUS-1D.
• Data sources:
  • Climatic data (precipitation in millimeters, temperature in degrees Celsius, wind speed in meters per second, solar radiation in watts per square meter, humidity in percent) from North Dakota Agricultural Weather Network (NDAWN) Oakes station and National Oceanic and Atmospheric Administration (NOAA) Lisbon station (1991–2024).
  • Hydrologic field observations: Snow Water Equivalent (SWE) measurements at 10 sites (winters of 2023 and 2024).
  • Soil Moisture Content (SMC) data from the PRESENS site near Oakes, ND, at depths of 50.8, 101.6, 203.2, 508, and 990.6 millimeters (2023 and 2024).
  • Soil properties, land cover (National Land Cover Database 2021), topography, depressional storage, and borehole lithology.

Main Results

• Spring and summer rainfall is the primary source of groundwater recharge, contributing approximately 80% of the annual recharge.
• Snowmelt contributes variably (approximately 20%) to annual recharge, with its contribution depending on frozen soil conditions and winter temperature; cold winters prolong soil freezing, reducing infiltration and increasing runoff.
• Groundwater recharge exhibits strong spatial variability, primarily controlled by soil type (coarser soils yield higher recharge, up to 58% of precipitation, while finer soils limit infiltration to 16%), followed by land cover, elevation, and surface depressions.
• Annual recharge is strongly correlated with yearly rainfall, but the influence of annual snowfall and average yearly temperature on recharge is highly variable.
• Climatic phases (e.g., cooling-wetting, drought) significantly impact recharge dynamics, with transition periods between phases often showing elevated recharge.
• Groundwater recharge (from both snowmelt and rainfall) is generally greater in cold years than in warm years due to increased snow storage and reduced evapotranspiration.
• The effect of land cover on recharge is limited in cold years, but the influence of soil type on recharge is robust regardless of precipitation and temperature conditions.
• Both CRHM and HYDRUS-1D models showed good agreement in simulating cumulative recharge and temporal dynamics, enhancing confidence in the recharge estimates.

Contributions

• Provides a robust framework for quantifying groundwater recharge in cold regions by integrating long-term field observations with process-based hydrological models (CRHM and HYDRUS-1D).
• Quantifies the relative contributions of snowmelt and rainfall to groundwater recharge in a cold region aquifer, identifying rainfall as the dominant source in the Oakes aquifer.
• Offers new insights into the complex interactions between snowmelt, rainfall, climate variability (including multi-year climatic phases), and landscape features (soil type, land cover, topography, depressions) in controlling groundwater recharge.
• Addresses key knowledge gaps regarding field-based recharge studies integrating physically based modeling in the climate-sensitive Northern Great Plains.
• Develops methods and insights applicable to other cold-region agricultural landscapes facing increasing climate variability.

Funding

• North Dakota Department of Water Resources (NDDWR)

Citation

@article{Mahmoud2025Groundwater,
  author = {Mahmoud, Hazem H. and Mahmood, Taufique H. and Korom, Scott F.},
  title = {Groundwater recharge dynamics to recent wetting in a cold region aquifer},
  journal = {Journal of Hydrology Regional Studies},
  year = {2025},
  doi = {10.1016/j.ejrh.2025.102902},
  url = {https://doi.org/10.1016/j.ejrh.2025.102902}
}