Sulca et al. (2026) An Integrated Analysis to Delineate Groundwater Flow Systems and Recharge Dynamics in the Chili River Sub-Basin, Southern Peru

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Identification

• Journal: Water
• Year: 2026
• Date: 2026-03-12
• Authors: Percy Sulca, Pablo A. García-Chevesich, Madeleine Guillen, Héctor L. Venegas-Quiñones, Roberto Pizarro, Brett Uhle, Francisco Alejo, John E. McCray
• DOI: 10.3390/w18060667

Research Groups

Not specified in the provided text.

Short Summary

This study characterizes the poorly understood aquifer systems, recharge mechanisms, and chemical evolution in the arid Chili River sub-basin, Peru. It identifies three aquifer types, distinct groundwater flow systems, and reveals a chemical evolution from high to low elevations, with high-altitude rainfall being the primary recharge source for wells.

Objective

• To delineate aquifer types, groundwater flow systems, and recharge dynamics across an elevation gradient in the arid Chili River sub-basin, southern Peru, to better characterize its critical groundwater resources.

Study Configuration

• Spatial Scale: Chili River sub-basin, 3246 square kilometres, with an elevation gradient of 2000–4000 metres above sea level.
• Temporal Scale: Snapshot characterization of hydrogeological and hydrochemical conditions based on field sampling.

Methodology and Data

• Models used: Not applicable; empirical methods including hydrogeological mapping, hydrochemistry, and stable-isotope tracing were used.
• Data sources:
  • Hydrogeological mapping.
  • Major-ion hydrochemistry (31 samples from springs and wells).
  • Stable-isotope tracing (δ18O and δ2H from 11 sources).

Main Results

• Three principal aquifer groups were identified: unconsolidated porous aquifers, fracture-controlled volcanic aquifers, and sedimentary fractured aquifers.
• Groundwater exhibits a chemical evolution from calcium-bicarbonate waters at high elevations to sodium-chloride waters in the lowlands.
• Local, intermediate, and regional groundwater flow systems were distinguished.
• Isotopic signatures confirm that wells are predominantly recharged by high-altitude rainfall (>4000 metres above sea level).
• Springs integrate water from multiple elevations through fractured volcanic formations.
• Elevated boron concentrations, linked to borate deposits on Pichupichu volcano, were found in supply springs, posing a potential health risk.

Contributions

• Provides the first integrated hydrogeological, hydrochemical, and isotopic characterization of the poorly understood groundwater systems in the Chili River sub-basin.
• Offers a scientific basis for informed groundwater management strategies, including recharge-zone protection, abstraction planning, and water-quality monitoring, critical for sustainable water supply in an arid region facing increasing urbanization and climatic variability.
• Identifies specific water quality concerns (boron contamination) relevant for public health and water resource management.

Funding

Not specified in the provided text.

Citation

@article{Sulca2026Integrated,
  author = {Sulca, Percy and García-Chevesich, Pablo A. and Guillen, Madeleine and Venegas-Quiñones, Héctor L. and Pizarro, Roberto and Uhle, Brett and Alejo, Francisco and McCray, John E.},
  title = {An Integrated Analysis to Delineate Groundwater Flow Systems and Recharge Dynamics in the Chili River Sub-Basin, Southern Peru},
  journal = {Water},
  year = {2026},
  doi = {10.3390/w18060667},
  url = {https://doi.org/10.3390/w18060667}
}