Kallon et al. (2026) Development and application of SWAT-MODFLOW in surface water-groundwater interactions: Current status and future challenges

Identification

• Journal: Environmental Earth Sciences
• Year: 2026
• Date: 2026-01-13
• Authors: Hadji Ds Kallon, Peiyue Li, Wenhai Shi
• DOI: 10.1007/s12665-025-12810-3

Research Groups

• School of Water and Environment, Chang’an University, Xi’an, Shaanxi, China
• Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Ministry of Education, Chang’an University, Xi’an, Shaanxi, China
• Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of the Ministry of Water Resources, Chang’an University, Xi’an, Shaanxi, China
• Institute of Environmental Management and Quality Control, Njala University, Freetown, Sierra Leone

Short Summary

This review synthesizes the development, applications, and challenges of the coupled SWAT-MODFLOW model for simulating surface water-groundwater interactions (SGIs), comparing its performance against standalone models and identifying future research directions for sustainable water management. It highlights the model's enhanced accuracy for integrated water resource simulations despite increased complexity and data requirements.

Objective

• To provide a comprehensive global review of the coupled SWAT-MODFLOW model, summarizing its current application status, identifying key challenges and assessing prediction accuracy, and explicitly comparing its performance with standalone SWAT and MODFLOW models for simulating surface water-groundwater interactions (SGIs).

Study Configuration

• Spatial Scale: Global review of applications, covering diverse scales from small watersheds to large river basins. Model grid resolutions typically range from 50 meters to 500 meters.
• Temporal Scale: Review period from 1999 to October 25, 2025. Applications reviewed involve simulation periods of 5 to 30 years, with daily or monthly time steps.

Methodology and Data

• Models used:
  • Coupled: SWAT-MODFLOW (including SWAT Grid-MODFLOW, SWAT Plus-MODFLOW, SWAT-MODFLOW-RT3D, SWAT-MODFLOW-MT3DMS, SWAT-MODFLOW-CF).
  • Standalone: Soil and Water Assessment Tool (SWAT), Modular Finite Difference Groundwater Flow Model (MODFLOW), Reactive Transport in 3D (RT3D), Modular Three-Dimensional Multi-Species Transport Model (MT3DMS).
  • Other mentioned (for context): MIKE SHE, GSFLOW (PRMS-MODFLOW), HydroGeoSphere (HGS), MODHMS, CATHY.
• Data sources:
  • Literature search: Scopus database (1999 to October 25, 2025), following PRISMA guidelines, analyzing 137 peer-reviewed articles.
  • Model input data (general for SWAT-MODFLOW applications): Detailed, high-resolution data on land use, soil properties, hydrogeological conditions, groundwater hydraulic parameters (e.g., hydraulic conductivity, specific yield), meteorological data (precipitation, temperature, wind speed, net radiation), digital elevation models (DEM), observation well data (groundwater heads), river size, and boundary conditions.
  • Analysis tools: VOSviewer (for keyword co-occurrence network), Geographic Information Systems (GIS), R, Python, Excel, and SPSS.

Main Results

• Research on SWAT-MODFLOW has grown significantly, with 79.5% of publications between 2020 and 2025, primarily in Asia, Europe, North America, and Africa.
• The coupled SWAT-MODFLOW model is a robust tool for simulating hydrological processes, solute transport, and climate change impacts on water resources, offering higher accuracy in water resource assessment and improved low-streamflow simulations compared to standalone models.
• Key applications include assessing climate change impacts (e.g., on groundwater recharge, water table dynamics, streamflow), water resource sustainability (e.g., groundwater extraction, irrigation effects), and nutrient transport to aquifers (e.g., nitrate nitrogen).
• SWAT-MODFLOW effectively incorporates various human activities (e.g., irrigation return flow, river-channel leakage) and land use changes, aligning better with basin management needs.
• The model's advantages come with increased complexity, higher data requirements (e.g., detailed groundwater heads, recharge, river-aquifer links), and higher computational costs (e.g., 3 to 6 times longer runtime for finer grids).
• Identified limitations and uncertainties include model structural issues (e.g., SWAT overestimating recharge in wet conditions), database ambiguity (e.g., hydrogeological data acquisition, observation well distribution), and parameterization-related uncertainty (e.g., non-uniqueness, requiring advanced calibration techniques).
• SWAT-MODFLOW is recommended for quantifying coupled responses to climate variability/extreme events with continuous (≥ 10 years) meteorological and groundwater monitoring data, or for integrated surface water-groundwater resource availability assessments. Standalone models are sufficient for specific focuses (e.g., surface runoff, long-term average groundwater recharge) with limited data or weak SGI.

Contributions

• This review provides a more comprehensive and refined understanding of SWAT-MODFLOW's application status, clarifying progress in emerging fields like extreme climate adaptation and micro-pollutant control over the past five years.
• It addresses gaps in prior reviews by systematically analyzing multi-solute migration mechanisms in SGI systems, constructing a multi-source uncertainty (parameter-structure-data) quantification framework, and elucidating uncertainty transfer laws of coupled models at the regional scale.
• It proposes a future research direction centered on "water quantity-water quality-ecology-carbon neutrality" collaboration, moving beyond optimizing single hydrological processes to address complex resource and environmental problems.

Funding

• National Natural Science Foundation of China (42472316)
• National Key Research and Development Program of China (2023YFC3706901)
• Fundamental Research Funds for the Central Universities (300102295201)

Citation

@article{Kallon2026Development,
  author = {Kallon, Hadji Ds and Li, Peiyue and Shi, Wenhai},
  title = {Development and application of SWAT-MODFLOW in surface water-groundwater interactions: Current status and future challenges},
  journal = {Environmental Earth Sciences},
  year = {2026},
  doi = {10.1007/s12665-025-12810-3},
  url = {https://doi.org/10.1007/s12665-025-12810-3}
}