Groundwater flow patterns in semi-arid mountainous alluvial aquifers: Hydrochemical and isotopic insights from the Central Bolivian Andes
Martinez, Virgilio LU
(2026)
In Groundwater for Sustainable Development
33.
- Abstract
- Groundwater stored in alluvial fan aquifers represents a key water resource in semi-arid mountainous regions, yet groundwater recharge mechanisms and flow dynamics remain poorly understood, particularly in data-scarce regions experiencing increasing water demand and anthropogenic pressure. This study investigates groundwater recharge processes and flow patterns in three adjacent watersheds of the Central Bolivian Andes characterized by complex alluvial fan aquifer systems. A combined hydrochemical and isotopic approach was applied using 149 hydrochemical samples and 59 stable isotope samples. Water samples were collected between 2022 and 2025 from rainwater, groundwater, springs, and surface water across different elevations. Rainwater... (More)
- Groundwater stored in alluvial fan aquifers represents a key water resource in semi-arid mountainous regions, yet groundwater recharge mechanisms and flow dynamics remain poorly understood, particularly in data-scarce regions experiencing increasing water demand and anthropogenic pressure. This study investigates groundwater recharge processes and flow patterns in three adjacent watersheds of the Central Bolivian Andes characterized by complex alluvial fan aquifer systems. A combined hydrochemical and isotopic approach was applied using 149 hydrochemical samples and 59 stable isotope samples. Water samples were collected between 2022 and 2025 from rainwater, groundwater, springs, and surface water across different elevations. Rainwater isotopic composition showed clear seasonal and altitudinal variations, with more depleted δ2H and δ18O values at higher elevations during the wet season, which is consistent with the amount effect. Groundwater is dominated by Ca2+–HCO3- facies with median TDS values of 149.5 mg/L, indicating low mineralization. Groundwater isotopic signatures (δ18O from −13.8‰ to −12.7‰) closely match depleted wet-season precipitation at high elevations, indicating a predominantly meteoric recharge controlled by high-altitude rainfall and infiltration along the upper parts of the alluvial fans. Recharge may also be locally influenced by surplus water discharged from a hydropower plant. The isotopic and hydrochemical similarity between groundwater and surface water indicates strong hydraulic connectivity within the aquifer system. Flow patterns appear controlled by heterogeneous alluvial stratigraphy and influenced by continuous well pumping. These factors, together with moderate nitrate concentrations detected in groundwater and surface water, suggest anthropogenic influences and emphasize the aquifer's vulnerability. These findings highlight the importance of high-altitude recharge zones and hydrological interventions in sustaining aquifers, with direct implications for long-term groundwater availability. The results are integrated into a hydrogeological conceptual model that improves understanding of recharge processes in mountain watersheds and provides insights applicable to similar data-scarce regions under anthropogenic pressures and semi-arid conditions. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/5eb40970-3f78-4b24-af39-45211d98efab
- author
- Martinez, Virgilio
LU
- contributor
- Gonzales, Andres
LU
; Mendoza, Alfredo
LU
; Rosberg, Jan-Erik
LU
; Barmen, Gerhard
LU
; Gkinis, Vasileios
and Bach, Jeppe
- organization
- publishing date
- 2026-03
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Groundwater for Sustainable Development
- volume
- 33
- article number
- 101620
- pages
- 17 pages
- publisher
- Elsevier
- external identifiers
-
- scopus:105034616504
- ISSN
- 2352-801X
- DOI
- 10.1016/j.gsd.2026.101620
- language
- English
- LU publication?
- yes
- id
- 5eb40970-3f78-4b24-af39-45211d98efab
- date added to LUP
- 2026-04-10 02:15:14
- date last changed
- 2026-04-17 11:02:02
@article{5eb40970-3f78-4b24-af39-45211d98efab,
abstract = {{Groundwater stored in alluvial fan aquifers represents a key water resource in semi-arid mountainous regions, yet groundwater recharge mechanisms and flow dynamics remain poorly understood, particularly in data-scarce regions experiencing increasing water demand and anthropogenic pressure. This study investigates groundwater recharge processes and flow patterns in three adjacent watersheds of the Central Bolivian Andes characterized by complex alluvial fan aquifer systems. A combined hydrochemical and isotopic approach was applied using 149 hydrochemical samples and 59 stable isotope samples. Water samples were collected between 2022 and 2025 from rainwater, groundwater, springs, and surface water across different elevations. Rainwater isotopic composition showed clear seasonal and altitudinal variations, with more depleted δ2H and δ18O values at higher elevations during the wet season, which is consistent with the amount effect. Groundwater is dominated by Ca2+–HCO3- facies with median TDS values of 149.5 mg/L, indicating low mineralization. Groundwater isotopic signatures (δ18O from −13.8‰ to −12.7‰) closely match depleted wet-season precipitation at high elevations, indicating a predominantly meteoric recharge controlled by high-altitude rainfall and infiltration along the upper parts of the alluvial fans. Recharge may also be locally influenced by surplus water discharged from a hydropower plant. The isotopic and hydrochemical similarity between groundwater and surface water indicates strong hydraulic connectivity within the aquifer system. Flow patterns appear controlled by heterogeneous alluvial stratigraphy and influenced by continuous well pumping. These factors, together with moderate nitrate concentrations detected in groundwater and surface water, suggest anthropogenic influences and emphasize the aquifer's vulnerability. These findings highlight the importance of high-altitude recharge zones and hydrological interventions in sustaining aquifers, with direct implications for long-term groundwater availability. The results are integrated into a hydrogeological conceptual model that improves understanding of recharge processes in mountain watersheds and provides insights applicable to similar data-scarce regions under anthropogenic pressures and semi-arid conditions.}},
author = {{Martinez, Virgilio}},
issn = {{2352-801X}},
language = {{eng}},
publisher = {{Elsevier}},
series = {{Groundwater for Sustainable Development}},
title = {{Groundwater flow patterns in semi-arid mountainous alluvial aquifers: Hydrochemical and isotopic insights from the Central Bolivian Andes}},
url = {{http://dx.doi.org/10.1016/j.gsd.2026.101620}},
doi = {{10.1016/j.gsd.2026.101620}},
volume = {{33}},
year = {{2026}},
}