Morphological and Hydrogeological Controls of Groundwater Flows and Water Age Distribution in Mountain Aquifers and Streams

Abstract Mountains are an essential source of the terrestrial component of the hydrological cycle, supplying high‐quality water to river networks and floodplain aquifers, especially during droughts. Traditionally, mountain hydrology has focused on shallow processes, overlooking the significance of d...

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Main Authors: A. Betterle, A. Bellin
Format: Article
Language:English
Published: Wiley 2024-11-01
Series:Water Resources Research
Subjects:
Online Access:https://doi.org/10.1029/2024WR037407
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author A. Betterle
A. Bellin
author_facet A. Betterle
A. Bellin
author_sort A. Betterle
collection DOAJ
description Abstract Mountains are an essential source of the terrestrial component of the hydrological cycle, supplying high‐quality water to river networks and floodplain aquifers, especially during droughts. Traditionally, mountain hydrology has focused on shallow processes, overlooking the significance of deep‐seated rock formations due to characterization challenges. Recent field studies have revealed that fractured rock formations can host rich aquifers despite their low permeability. Nonetheless, it is unclear how deep flows interact with the overall hydrological functioning of mountain areas, how they contribute to the long‐term water budget, and how climate, morphology, and geology jointly control them. Through numerical simulations, we have gained new insights into mountain aquifers, addressing (a) the proportion of groundwater base flow and its age distribution, (b) water storage and its sensitivity to groundwater recharge, (c) the impact of long term mean recharge on the extent of the groundwater‐fed surface drainage network under various morphological and geological settings. We showed that subsurface travel times follow a Gamma distribution, whose parameters are modulated by recharge, hydraulic conductivity, and topography. High recharge and strong decay with depth of the hydraulic conductivity in a hilly topography lead to a shallow water table mimicking the surface topography and spatially distributed low‐intensity outflows that feed a dense drainage network. In rugged catchments, the groundwater contribution intensifies and concentrates in the downstream portion of the river network as recharge declines. These findings can help assess how a changing climate might impact hydrological regimes under various geomorphological conditions and identify sustainable water uses in mountain environments.
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spelling doaj-art-3ddfcdf2cf9e4e548834b84db4f801a82025-08-23T13:05:51ZengWileyWater Resources Research0043-13971944-79732024-11-016011n/an/a10.1029/2024WR037407Morphological and Hydrogeological Controls of Groundwater Flows and Water Age Distribution in Mountain Aquifers and StreamsA. Betterle0A. Bellin1Joint Research Centre European Commission Ispra ItalyDepartment of Civil Environmental and Mechanical Engineering University of Trento Trento ItalyAbstract Mountains are an essential source of the terrestrial component of the hydrological cycle, supplying high‐quality water to river networks and floodplain aquifers, especially during droughts. Traditionally, mountain hydrology has focused on shallow processes, overlooking the significance of deep‐seated rock formations due to characterization challenges. Recent field studies have revealed that fractured rock formations can host rich aquifers despite their low permeability. Nonetheless, it is unclear how deep flows interact with the overall hydrological functioning of mountain areas, how they contribute to the long‐term water budget, and how climate, morphology, and geology jointly control them. Through numerical simulations, we have gained new insights into mountain aquifers, addressing (a) the proportion of groundwater base flow and its age distribution, (b) water storage and its sensitivity to groundwater recharge, (c) the impact of long term mean recharge on the extent of the groundwater‐fed surface drainage network under various morphological and geological settings. We showed that subsurface travel times follow a Gamma distribution, whose parameters are modulated by recharge, hydraulic conductivity, and topography. High recharge and strong decay with depth of the hydraulic conductivity in a hilly topography lead to a shallow water table mimicking the surface topography and spatially distributed low‐intensity outflows that feed a dense drainage network. In rugged catchments, the groundwater contribution intensifies and concentrates in the downstream portion of the river network as recharge declines. These findings can help assess how a changing climate might impact hydrological regimes under various geomorphological conditions and identify sustainable water uses in mountain environments.https://doi.org/10.1029/2024WR037407river base flowresidence timewater agemountain aquifersgroundwaterclimate change impact on groundwater
spellingShingle A. Betterle
A. Bellin
Morphological and Hydrogeological Controls of Groundwater Flows and Water Age Distribution in Mountain Aquifers and Streams
Water Resources Research
river base flow
residence time
water age
mountain aquifers
groundwater
climate change impact on groundwater
title Morphological and Hydrogeological Controls of Groundwater Flows and Water Age Distribution in Mountain Aquifers and Streams
title_full Morphological and Hydrogeological Controls of Groundwater Flows and Water Age Distribution in Mountain Aquifers and Streams
title_fullStr Morphological and Hydrogeological Controls of Groundwater Flows and Water Age Distribution in Mountain Aquifers and Streams
title_full_unstemmed Morphological and Hydrogeological Controls of Groundwater Flows and Water Age Distribution in Mountain Aquifers and Streams
title_short Morphological and Hydrogeological Controls of Groundwater Flows and Water Age Distribution in Mountain Aquifers and Streams
title_sort morphological and hydrogeological controls of groundwater flows and water age distribution in mountain aquifers and streams
topic river base flow
residence time
water age
mountain aquifers
groundwater
climate change impact on groundwater
url https://doi.org/10.1029/2024WR037407
work_keys_str_mv AT abetterle morphologicalandhydrogeologicalcontrolsofgroundwaterflowsandwateragedistributioninmountainaquifersandstreams
AT abellin morphologicalandhydrogeologicalcontrolsofgroundwaterflowsandwateragedistributioninmountainaquifersandstreams