Sun et al. (2025) Study on the response mechanism of groundwater to rainfall in different geomorphic units of semi-arid regions

Identification

• Journal: Journal of Hydrology Regional Studies
• Year: 2025
• Date: 2025-11-22
• Authors: Jiahao Sun, Yongzhi Bao, Tingxi Liu, Limin Duan, Zhiting Wang, Xinyu Guo, Vijay P. Singh
• DOI: 10.1016/j.ejrh.2025.102971

Research Groups

• State Key Laboratory of Water Engineering Ecology and Environment in Arid Area, Inner Mongolia Agricultural University, Hohhot, China
• Inner Mongolia Key Laboratory of Ecohydrology and High-Efficient Utilization of Water Resources, Hohhot, China
• Autonomous Region Collaborative Innovation Center for Integrated Management of Water Resources and Water Environment in the Inner Mongolia Reaches of the Yellow River, Hohhot, China
• Department of Biological and Agricultural Engineering & Zachry Department of Civil Engineering, Texas A& M University, College Site, TX, USA

Short Summary

This study investigated groundwater level responses to precipitation across different geomorphic units and aquifer types in the Horqin Sandy Land from 2016 to 2023, revealing distinct groundwater dynamics, memory effects, and rainfall lag times primarily governed by soil permeability and groundwater depth.

Objective

• Exploration of the response mechanisms of groundwater depth to precipitation in arid and semi-arid environments.
• Characterization of the hydrodynamic behavior and hydraulic properties of aquifers, and investigation of the hydrogeological features across different stratigraphic layers.
• Analysis of the resonance cycle between precipitation events and groundwater dynamics, with a particular focus on quantifying lag times in groundwater response to rainfall.

Study Configuration

• Spatial Scale: Agula Eco-hydrological Experimental Station, southeastern Horqin Sandy Land, Tongliao City, Inner Mongolia, North China (43°18′48″–43°21′2″ N, 122°32′30″–122°41′00″ E), approximately 55 km².
• Temporal Scale: Daily records from 2016 to 2023.

Methodology and Data

• Models used: Normalized Groundwater Level (GWL) method, Loess Seasonal and Trend Decomposition (STL), Continuous Wavelet Transform (CWT), Cross-Wavelet Transform (XWT), Wavelet Coherence, Autocorrelation analysis, Cross-correlation analysis, Monte Carlo simulation.
• Data sources: Groundwater level data from 24 representative observation wells (out of 78 total) equipped with HOBO automatic water level recorders (1-hour intervals), and daily rainfall data from 13 automated monitoring stations.

Main Results

• Groundwater Level Trends (2016-2023):
  • Phreatic aquifers: Groundwater levels rose by 0.64–0.97 m in dunes (mobile dunes: 0.97 m; fixed dunes: 0.78 m; semi-fixed dunes: 0.64 m), while remaining relatively stable or slightly declining in meadows.
  • Weakly confined aquifers: Groundwater levels rose by 0.33–1.08 m (mobile dunes: 0.33 m; semi-fixed dunes: 0.66 m; fixed dunes: 1.08 m; meadows: 0.77 m).
• Seasonal Fluctuations:
  • Seasonal components exerted the strongest influence on groundwater levels in meadows for both aquifer types.
  • Seasonal fluctuations peaked at 1 m in meadow phreatic aquifers and 0.55 m in meadow weakly confined aquifers.
  • The wet period in the weakly confined aquifer typically began 1–2 months later than in the phreatic aquifer due to the blocking effect of the weakly permeable layer.
• Aquifer Memory Effects (Decorrelation Times):
  • Phreatic aquifers: Decorrelation times ranged from 21–40 days (meadows: 21–34 days; fixed dunes: 8–33 days; semi-fixed dunes: 28–36 days; mobile dunes: 28–40 days), with mobile and semi-fixed dunes showing stronger memory.
  • Weakly confined aquifers: Decorrelation times ranged from 16–29 days (meadows: 16–21 days; semi-fixed dunes: 21–28 days; mobile dunes: 27–29 days; fixed dunes: 22–26 days), with mobile dunes exhibiting stronger memory and meadows the weakest.
• Rainfall Response Lags:
  • A dominant oscillation period of 256–512 days for rainfall-groundwater level coherence was identified across all geomorphic units.
  • Phreatic aquifers: Average lag times ranged from 1 day (meadows) to 55 days (semi-fixed dunes).
  • Weakly confined aquifers: Average lag times ranged from 61.3 days (fixed dunes) to 113.5 days (mobile dunes).
  • Groundwater depth (D) showed a significant positive correlation with lag time (LT) (Pearson r = 0.79, p < 0.01) and decorrelation time (DT) (Pearson r = 0.66, p < 0.01).
  • Permeability coefficient (lnK) showed a significant negative correlation with decorrelation time (DT) (Pearson r = -0.49, p = 0.02).

Contributions

• Provides a comprehensive understanding of groundwater-precipitation response mechanisms by integrating multiple time-series analysis techniques across diverse geomorphic units and aquifer types in a semi-arid sandy region.
• Quantifies key hydrological parameters such as seasonal variability, aquifer memory effects (decorrelation times), and rainfall lag times, offering specific insights for the Horqin Sandy Land.
• Identifies groundwater depth and soil permeability as the primary controlling factors influencing groundwater dynamics and response lags.
• Offers a scientific basis for improved groundwater management and ecosystem restoration strategies in similar desertified regions globally.

Funding

• National Natural Science Foundation of China (Grant Nos. 52439004 and 52309021)
• National Natural Science Foundation of Inner Mongolia (Grant No. 2025MS05063)
• National Key Research and Development Program of China (Grant No. 2024YFF1306302)
• Inner Mongolia Agricultural University Basic Research Project (Grant No. BR251403)
• Inner Mongolia Autonomous Region Science and Technology Leading Talent Team (Grant No. 2022LJRC0007)
• Special Project of Water Conservancy Science and Technology of Inner Mongolia Autonomous Region (Grant No. NSLKJ2024002-02)
• Science and Technology Project of Inner Mongolia Autonomous Region (Grant No. 2025YFEH0170-02)
• Inner Mongolia Agricultural University Basic Research Project (Grant Nos. BR221012, BR221204 and BR251018)
• First-class Academic Subjects Special Research Project of the Education Department of Inner Mongolia Autonomous Region (Grant Nos. YLXKZX-NND-010 and YLXKZX-NND-028)

Citation

@article{Sun2025Study,
  author = {Sun, Jiahao and Bao, Yongzhi and Liu, Tingxi and Duan, Limin and Wang, Zhiting and Guo, Xinyu and Singh, Vijay P.},
  title = {Study on the response mechanism of groundwater to rainfall in different geomorphic units of semi-arid regions},
  journal = {Journal of Hydrology Regional Studies},
  year = {2025},
  doi = {10.1016/j.ejrh.2025.102971},
  url = {https://doi.org/10.1016/j.ejrh.2025.102971}
}