Chen et al. (2026) Combined effect of tides, irregular waves and beach recovery on groundwater flow and marine-sourced salt transport in coastal unconfined aquifers

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-03-06
• Authors: Weilun Chen, Jun Kong, Jun Wang, Saihua Huang, Huawei Xie, Chao Gao
• DOI: 10.1016/j.jhydrol.2026.135258

Research Groups

• School of Hydraulic Engineering, Zhejiang University of Water Resources and Electric Power, Hangzhou, China
• Key Laboratory of Coastal Disaster and Protection (Hohai University), Ministry of Education, Nanjing, China
• College of Civil and Architectural Engineering, Taishan University, Taian, China

Short Summary

This study numerically investigates the combined impact of tides and irregular waves on groundwater dynamics and marine-sourced salt transport during beach recovery. It reveals that wave action, particularly overtopping waves, significantly amplifies subsurface mixing and solute transport, leading to substantial increases in intertidal saline infiltration and submarine groundwater discharge.

Objective

• To investigate the combined effect of tides and irregular waves on groundwater dynamics and marine-sourced salt transport in coastal unconfined aquifers during beach recovery.

Study Configuration

• Spatial Scale: Coastal unconfined aquifers, specifically sandy beach environments, modeled using three generalized beach profiles (berm, storm, and linear profiles).
• Temporal Scale: Processes occurring during beach recovery, which can span years, focusing on the dynamic hydrogeological responses to tides and irregular waves.

Methodology and Data

• Models used: Numerical modeling approach (specific model name not provided).
• Data sources: Idealized/synthetic data for generalized beach profiles and hydrodynamic conditions (tides and irregular waves).

Main Results

• Compared to tidal-only conditions, non-overtopping waves amplify differences in upper saline plume (USP) features (area and salt content) and salt-freshwater mixing zones between berm and storm profiles.
• Overtopping waves further magnify these differences due to high-salinity zones formed by infiltration of ponding water in backshore depressions behind berms.
• Wave action introduces additional deceleration phases in particle movement, leading to more complex travel speed distributions.
• Overtopping waves intensify water and salt exchange across the aquifer, elevating intertidal saline infiltration (ISI) by up to 1248% and submarine groundwater discharge (SGD) by up to 182%.

Contributions

• First to investigate the combined effect of tides and irregular waves, including wave overtopping, on groundwater flow and marine-sourced salt transport during the multi-year process of beach recovery.
• Quantifies the significant enhancement of subsurface mixing and solute transport, specifically ISI and SGD, due to wave overtopping.
• Provides insights crucial for managing seawater intrusion in vulnerable coastal areas by highlighting the critical role of wave overtopping.

Funding

• Not specified in the provided text.

Citation

@article{Chen2026Combined,
  author = {Chen, Weilun and Kong, Jun and Wang, Jun and Huang, Saihua and Xie, Huawei and Gao, Chao},
  title = {Combined effect of tides, irregular waves and beach recovery on groundwater flow and marine-sourced salt transport in coastal unconfined aquifers},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.135258},
  url = {https://doi.org/10.1016/j.jhydrol.2026.135258}
}