Tajima et al. (2026) Climate Change Alters Post‐Surge Recovery of Coastal Aquifers

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Water Resources Research
• Year: 2026
• Date: 2026-03-01
• Authors: Satoshi Tajima, René Therrien, Philip Brunner
• DOI: 10.1029/2025wr042142

Research Groups

Not available in the provided abstract.

Short Summary

This study quantifies the combined effects of increasing storm-surge intensity and decreasing frequency on coastal aquifers using integrated numerical simulations. It reveals two distinct long-term regimes—full recovery or shifted equilibrium with persistent salt accumulation—determined by critical thresholds of storm intensity and frequency, which can be predicted by a dimensionless number.

Objective

• To quantify the combined effects of increased storm-surge intensity and reduced frequency on the recovery of coastal aquifers subject to recurrent wave overwash events, using surface–subsurface integrated numerical simulations of a generalized island aquifer across 12 scenarios with varying storm-surge frequency and intensity.

Study Configuration

• Spatial Scale: Generalized island aquifer (conceptual/idealized island scale).
• Temporal Scale: Long-term, multi-event scale, focusing on persistent changes and recovery over time.

Methodology and Data

• Models used: Surface–subsurface integrated numerical simulations.
• Data sources: Not applicable; the study uses numerical simulations across 12 varying scenarios of storm-surge frequency and intensity, rather than external observational or reanalysis data.

Main Results

• Two distinct long-term regimes emerge: (a) full recovery, where the aquifer returns to pre-surge conditions if storm intensity and frequency remain below critical thresholds, and (b) shifted equilibrium, characterized by persistent salt accumulation and depleted fresh groundwater availability if these thresholds are exceeded.
• Higher hydraulic conductivity and smaller island width exacerbate salt accumulation; the former by increasing the salt load introduced during each storm-surge event, and the latter by decelerating subsequent flushing.
• The transition between recovery and shifted-equilibrium regimes can be represented with a dimensionless number (Ω) that integrates the effect of storm-surge intensity and frequency on salt load.
• In a shifted equilibrium regime, the excess salt load at new dynamic equilibria is effectively approximated by linear functions of Ω.

Contributions

• Offers a straightforward framework and tool for the preliminary assessment of climate-change impacts on coastal groundwater systems.
• Provides insights particularly relevant for small islands with limited and vulnerable freshwater resources.
• Supports the development of proactive water security strategies against climate change.
• Introduces a dimensionless number (Ω) to predict the transition between aquifer recovery and shifted equilibrium regimes.

Funding

Not available in the provided abstract.

Citation

@article{Tajima2026Climate,
  author = {Tajima, Satoshi and Therrien, René and Brunner, Philip},
  title = {Climate Change Alters Post‐Surge Recovery of Coastal Aquifers},
  journal = {Water Resources Research},
  year = {2026},
  doi = {10.1029/2025wr042142},
  url = {https://doi.org/10.1029/2025wr042142}
}