Shi et al. (2026) Elucidating the hydrochemical and isotopic processes of surface and groundwater in response to river drying up and re-flowing in an alluvial-proluvial fan-plain transition zone

Identification

Journal: CATENA
Year: 2026
Date: 2026-02-15
Authors: Xiaoxin Shi, Hui Qian, Yanyan Gao, Yixin Liu, Siqi Li, Xinjie Xu, Shunqi Tang
DOI: 10.1016/j.catena.2026.109916

Research Groups

School of Water and Environment, Chang'an University, Xi'an 710054, Shaanxi, China
Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Chang'an University, Xi'an 710054, 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 710054, Shaanxi, China
State Key Laboratory of Loess Science, Chang'an University, Xi'an 710054, Shaanxi, China
Hydrological and Water Resources Survey Bureau of Xiangyang City, Hubei Province, China

Short Summary

This study elucidates surface water-groundwater (SW-GW) interactions during river drying and re-flowing in an alluvial-proluvial fan-plain transition zone using hydrochemistry and stable isotopes. It identifies three distinct transformation zones and quantifies the seasonal contributions between SW and GW, revealing that river drying is primarily caused by efficient infiltration into groundwater.

Objective

To elucidate the hydrochemical and isotopic processes of surface water-groundwater transformations associated with localized river drying and re-flowing in the alluvial-proluvial fan-plain transition zone of the Hei River.
To identify surface water-groundwater interactions and quantify the contributions of different water sources using water level, hydrochemistry, and δD-δ18O isotopes, combined with a Monte Carlo-based end-member mixing analysis.

Study Configuration

Spatial Scale: Alluvial-proluvial fan-plain transition zone of the Hei River, at the northern foot of the Qinling Mountains, China. The study covers the area from the mountain outlet to the plain, including apex to mid-fan, forefront of the fan, and plain sections.
Temporal Scale: Multiple sampling periods, covering seasonal variations (e.g., summer and winter).

Methodology and Data

Models used: Monte Carlo (MC)-based end-member mixing analysis (EMMA).
Data sources: Water level measurements, hydrochemical analyses, and stable isotope (δD-δ18O) analyses. Original hydrochemical research data was also utilized.

Main Results

Three distinct surface water-groundwater transformation zones were identified from the mountain outlet to the plain.
In the apex to mid-fan area, surface water infiltrates through highly permeable coarse-grained sediments, leading to localized river drying. Surface water contributed 24.8%–57.7% to groundwater across sampling periods.
In the forefront of the fan, groundwater discharges via springs due to gentler topography and finer aquifer materials, driving river re-flowing. Groundwater contributed 42.2%–50.5% to surface water in this section.
In the plain, renewed surface water infiltration occurs, with surface water contributing 31.8%–54.9% to groundwater.
Seasonally, groundwater contributed more to surface water in winter, while surface water replenished groundwater more in summer.
Regional river drying in the alluvial-proluvial fan is fundamentally a result of efficient infiltration of river water into groundwater, indicating substantial groundwater storage capacity and tight surface water-groundwater connectivity.

Contributions

Advances the understanding of hydrological processes under river drying-re-flow conditions, particularly the mechanisms governing surface water-groundwater interactions in such dynamic environments.
Provides insights for water resource management in similar regions facing river drying and re-flowing phenomena.

Funding

Not explicitly mentioned in the provided text.

Citation

@article{Shi2026Elucidating,
  author = {Shi, Xiaoxin and Qian, Hui and Gao, Yanyan and Liu, Yixin and Li, Siqi and Xu, Xinjie and Tang, Shunqi},
  title = {Elucidating the hydrochemical and isotopic processes of surface and groundwater in response to river drying up and re-flowing in an alluvial-proluvial fan-plain transition zone},
  journal = {CATENA},
  year = {2026},
  doi = {10.1016/j.catena.2026.109916},
  url = {https://doi.org/10.1016/j.catena.2026.109916}
}

Original Source: https://doi.org/10.1016/j.catena.2026.109916