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| Titel |
Origin and assessment of deep groundwater inflow in the Ca' Lita landslide using hydrochemistry and in situ monitoring |
| VerfasserIn |
F. Cervi, F. Ronchetti, G. Martinelli, T. A. Bogaard, A. Corsini |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 11 ; Nr. 16, no. 11 (2012-11-13), S.4205-4221 |
| Datensatznummer |
250013568
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| Publikation (Nr.) |
 copernicus.org/hess-16-4205-2012.pdf |
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| Zusammenfassung |
Changes in soil water content, groundwater flow and a rise in pore water
pressure are well-known causal or triggering factors for hillslope
instability. Rainfall and snowmelt are generally assumed as the main sources
of groundwater recharge. This assumption neglects the role of deep water
inflow in highly tectonized areas, a factor that can influence long-term
pore-pressure regimes and play a role on local slope instability.
This paper aims to assess the origin of groundwater in the Ca' Lita
landslide (northern Italian Apennines) and to qualify and quantify the
aliquot attributable to deep water inflow. The research is essentially based
on in situ monitoring and hydrochemical analyses. It involved 5 yr of
continuous monitoring of groundwater levels, electrical conductivity and
temperature and with groundwater sampling followed by determination of
major ions (Na+, K+, Mg2+, Ca2+, Cl−,
HCO3−, SO42−), tracers (such as Btot and
Sr2+), and isotopes (δ18O, δ2H and 3H).
Leaching experiments on soil samples, hydrochemical modelling and water
recharge estimation were also carried out.
Results show that the groundwater balance in the Ca' Lita landslide must
take into account an inflow of deep and highly mineralised Na-SO4 water
(more than 9500 μS cm−1) with non-negligible amounts of Cl−
(up to 800 mg l−1). The chemical and isotopic fingerprint of this
water points to oilfield water hosted at large depths in the Apennine chain
and that uprises through a regional fault line crossing the landslide area.
It recharges the aquifer hosted in the bedrock underlying the sliding
surface (at a rate of about 49 000–85 700 m3 yr−1) and it also
partly recharges the landslide body. In both the aquifers, the hydrochemical
imprint of deep water mixed with rainfall and snowmelt water was observed.
This indicates a probable influence of deep water inflow on the mobility of
the Ca' Lita landslide, a finding that could be applicable to other large
landslides occurring in highly tectonized areas in the northern Apennines or
in other mountain chains. The paper demonstrates that hydrochemistry should,
therefore, be considered as a valuable investigation method to define
hydrogeological limits and the groundwater sources in hillslope and to
assess groundwater flow patterns in deep-seated landslides. |
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