Lee et al. (2025) Future variability in groundwater-surface water interactions: Implications for streamflow and its components using SWAT-MODFLOW 6 and CMIP 6 projections

Identification

• Journal: Journal of Hydrology
• Year: 2025
• Date: 2025-11-01
• Authors: Suh-Ho Lee, Hyeji Kim, In-Hee Cho, Seong‐Sun Lee, Hyemin Park, Youn-Tae Kim, Moonsu Kim, Kang‐Kun Lee
• DOI: 10.1016/j.jhydrol.2025.134511

Research Groups

• School of Earth and Environmental Sciences, Seoul National University, Seoul, Republic of Korea
• National Institute of Environmental Research, Incheon, Republic of Korea

Short Summary

This study investigates the future variability of groundwater-surface water interactions and their implications for streamflow and its components under climate change using integrated hydrological and climate models. Projections indicate an increase in average streamflow, a decrease in the baseflow index due to intensified surface runoff, and a higher probability of flooding under the SSP 5–8.5 scenario.

Objective

• To investigate the impact of increasing precipitation variability on baseflow and surface runoff over centennial timescales by integrating the SWAT, MODFLOW 6, and CMIP 6 SSP scenarios.

Study Configuration

• Spatial Scale: A watershed located in Nonsan city, Republic of Korea.
• Temporal Scale: Centennial timescales, covering historical and future climate projections (up to the 2080s).

Methodology and Data

• Models used: SWAT (Soil and Water Assessment Tool), MODFLOW 6, CMIP 6 (Coupled Model Intercomparison Project Phase 6) Shared Socioeconomic Pathway (SSP) scenarios (specifically SSP 5–8.5).
• Data sources: CMIP 6 climate projections, observed streamflow (for SWAT calibration/validation), observed groundwater levels (for MODFLOW 6 calibration/validation).

Main Results

• SWAT effectively reproduces observed streamflow, and MODFLOW 6 accurately simulates groundwater levels.
• MODFLOW 6 baseflow simulations performed well during low-flow periods.
• Under the SSP 5–8.5 scenario, the average streamflow rate is projected to increase to 23.7 cubic meters per second.
• The baseflow index (BFI) is projected to decrease due to intensified surface runoff and more frequent flooding events.
• The probability of flood occurrence is projected to rise to 10.6 %.
• Trend analysis suggests an increasing contribution of surface runoff by the 2080s, highlighting the growing hydrological impact of climate change.

Contributions

• Provides a comprehensive framework for assessing future groundwater-surface water interactions and their hydrological impacts by integrating SWAT, MODFLOW 6, and CMIP 6 SSP scenarios.
• Offers critical insights into the long-term variability of baseflow, surface runoff, and flood frequency under climate change, particularly in a region sensitive to water resource variability.
• Emphasizes the urgent need for integrated water resource management strategies to mitigate future hydrological risks and enhance resilience to climate variability.

Funding

[No specific funding information was provided in the abstract or introduction of the paper.]

Citation

@article{Lee2025Future,
  author = {Lee, Suh-Ho and Kim, Hyeji and Cho, In-Hee and Lee, Seong‐Sun and Park, Hyemin and Kim, Youn-Tae and Kim, Moonsu and Lee, Kang‐Kun},
  title = {Future variability in groundwater-surface water interactions: Implications for streamflow and its components using SWAT-MODFLOW 6 and CMIP 6 projections},
  journal = {Journal of Hydrology},
  year = {2025},
  doi = {10.1016/j.jhydrol.2025.134511},
  url = {https://doi.org/10.1016/j.jhydrol.2025.134511}
}