Delineating Ababi Mountains spring recharge zones using combined isotope hydrology and geophysical methods

Sustainable groundwater management requires accurate identification of spring recharge zones, particularly in volcanic regions where water resources are critical. This study aimed to delineate the groundwater recharge zone of the Ababi Spring in Bali’s Karangasem Regency by integrating isotope hydro...

Full description

Saved in:
Bibliographic Details
Main Authors: I Nengah Simpen, I Wayan Redana, Putu Doddy Heka Ardana
Format: Article
Language:English
Published: Polish Academy of Sciences 2025-03-01
Series:Journal of Water and Land Development
Subjects:
Online Access:https://journals.pan.pl/Content/134330/2025-01-JWLD-18.pdf
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849338397765664768
author I Nengah Simpen
I Wayan Redana
Putu Doddy Heka Ardana
author_facet I Nengah Simpen
I Wayan Redana
Putu Doddy Heka Ardana
author_sort I Nengah Simpen
collection DOAJ
description Sustainable groundwater management requires accurate identification of spring recharge zones, particularly in volcanic regions where water resources are critical. This study aimed to delineate the groundwater recharge zone of the Ababi Spring in Bali’s Karangasem Regency by integrating isotope hydrological and geophysical techniques. Water samples were collected from five locations (211–978 m a.s.l.) and analysed for stable isotopes (δ2H or δD and δ18O). Vertical electrical sounding and audio magnetotelluric surveys were conducted to validate findings and map subsurface structures. The local meteoric water line was established (δ2H = 4.4912δ18O + 7.1419) and an isotope-elevation relationship was developed. The spring water exhibited depleted isotopic values (δ18O: −7.706‰, δ2H: −39.748‰) compared to local precipitation, indicating a higher-altitude source. The analysis identified the recharge zone at approximately 2,118 m a.s.l. Geophysical surveys revealed subsurface structures connecting the recharge area to the spring, with resistivity patterns indicating preferential flow paths going through fractured volcanic rocks. The effectiveness of this integrated approach was further validated through additional isotopic analysis of rainfall at 1,514 m a.s.l. This supported the established isotope-elevation relationship model (R2 = 0.6847). The study demonstrates the value of combining hydrochemical and geophysical methods for accurate recharge zone delineation in a volcanic terrain, particularly in regions with complex hydrogeological settings. These findings provide crucial information for implementing targeted conservation strategies and ensuring sustainable water resource management in the Karangasem region, while establishing a methodological framework applicable to similar volcanic environments.
format Article
id doaj-art-3a71a132d68c443280845fc8b0ea047c
institution Kabale University
issn 2083-4535
language English
publishDate 2025-03-01
publisher Polish Academy of Sciences
record_format Article
series Journal of Water and Land Development
spelling doaj-art-3a71a132d68c443280845fc8b0ea047c2025-08-20T03:44:24ZengPolish Academy of SciencesJournal of Water and Land Development2083-45352025-03-01No 64163171https://doi.org/10.24425/jwld.2025.153529Delineating Ababi Mountains spring recharge zones using combined isotope hydrology and geophysical methodsI Nengah Simpen0https://orcid.org/0009-0009-0535-9083I Wayan Redana1https://orcid.org/0009-0006-9192-6002Putu Doddy Heka Ardana2https://orcid.org/0000-0003-1300-9728Udayana University, Faculty of Mathematics and Natural Sciences, Physics Study Program, Kampus Bukit Jimbaran, Denpasar, Bali, 80361, IndonesiaUdayana University, Postgraduate Faculty, Professional Engineer Education Study Program, Denpasar, Jl. Raya Kampus UNUD, Kampus Bukit Jimbaran, Jimbaran, Kuta Selantan, Kabupaten Badung, Bali 80361, IndonesiaNgurah Rai University, Faculty of Science and Technology, Civil Engineering Study Program, Jl. Kampus Ngurah Rai No. 30, Penatih, Kec. Denpasar Tim., Kota Denpasar, Bali 80238, IndonesiaSustainable groundwater management requires accurate identification of spring recharge zones, particularly in volcanic regions where water resources are critical. This study aimed to delineate the groundwater recharge zone of the Ababi Spring in Bali’s Karangasem Regency by integrating isotope hydrological and geophysical techniques. Water samples were collected from five locations (211–978 m a.s.l.) and analysed for stable isotopes (δ2H or δD and δ18O). Vertical electrical sounding and audio magnetotelluric surveys were conducted to validate findings and map subsurface structures. The local meteoric water line was established (δ2H = 4.4912δ18O + 7.1419) and an isotope-elevation relationship was developed. The spring water exhibited depleted isotopic values (δ18O: −7.706‰, δ2H: −39.748‰) compared to local precipitation, indicating a higher-altitude source. The analysis identified the recharge zone at approximately 2,118 m a.s.l. Geophysical surveys revealed subsurface structures connecting the recharge area to the spring, with resistivity patterns indicating preferential flow paths going through fractured volcanic rocks. The effectiveness of this integrated approach was further validated through additional isotopic analysis of rainfall at 1,514 m a.s.l. This supported the established isotope-elevation relationship model (R2 = 0.6847). The study demonstrates the value of combining hydrochemical and geophysical methods for accurate recharge zone delineation in a volcanic terrain, particularly in regions with complex hydrogeological settings. These findings provide crucial information for implementing targeted conservation strategies and ensuring sustainable water resource management in the Karangasem region, while establishing a methodological framework applicable to similar volcanic environments.https://journals.pan.pl/Content/134330/2025-01-JWLD-18.pdfaudio magnetotelluricgroundwater rechargeisotope hydrologyspring watervolcanic aquifer
spellingShingle I Nengah Simpen
I Wayan Redana
Putu Doddy Heka Ardana
Delineating Ababi Mountains spring recharge zones using combined isotope hydrology and geophysical methods
Journal of Water and Land Development
audio magnetotelluric
groundwater recharge
isotope hydrology
spring water
volcanic aquifer
title Delineating Ababi Mountains spring recharge zones using combined isotope hydrology and geophysical methods
title_full Delineating Ababi Mountains spring recharge zones using combined isotope hydrology and geophysical methods
title_fullStr Delineating Ababi Mountains spring recharge zones using combined isotope hydrology and geophysical methods
title_full_unstemmed Delineating Ababi Mountains spring recharge zones using combined isotope hydrology and geophysical methods
title_short Delineating Ababi Mountains spring recharge zones using combined isotope hydrology and geophysical methods
title_sort delineating ababi mountains spring recharge zones using combined isotope hydrology and geophysical methods
topic audio magnetotelluric
groundwater recharge
isotope hydrology
spring water
volcanic aquifer
url https://journals.pan.pl/Content/134330/2025-01-JWLD-18.pdf
work_keys_str_mv AT inengahsimpen delineatingababimountainsspringrechargezonesusingcombinedisotopehydrologyandgeophysicalmethods
AT iwayanredana delineatingababimountainsspringrechargezonesusingcombinedisotopehydrologyandgeophysicalmethods
AT putudoddyhekaardana delineatingababimountainsspringrechargezonesusingcombinedisotopehydrologyandgeophysicalmethods