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| Titel |
Water dynamics and groundwater contributions in a young mountain soil under different meteorological conditions |
| VerfasserIn |
Amro Negm, Marco Falocchi, Stefano Barontini, Roberto Ranzi, Baldassare Bacchi |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096141
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| Publikation (Nr.) |
 EGU/EGU2014-11630.pdf |
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| Zusammenfassung |
| Groundwater contribution to the soil–water content and to the evapotranspiration is a major
uncertainty to assess the water balance. Particularly in mountain environments, where the soil
and the depth of the water table are shallow, both percolation and water rise from the water
table can happen.
Aiming at better understanding these processes at the local scale, a micrometeorological
station, equipped with both traditional sensors, an eddy covariance (EC) apparatus with a
20Hz sonic anemometer and infrared CO2 and H2O gas analyser, and four multiplexed
TDR probes, was installed at Cividate Camuno (Oglio river basin, Central Italian
Alps, Italy, 274ma.s.l.), in a mountain environment with complex topography and
Alpine sublitoranean climate. The young, anthropised, soil upper layers are about
40cm deep and mainly covered by alfalfa (Medicago sativa), wild carrot (Daucus
carota) and yarrow (Achillea millefolium). Field and laboratory tests were performed
to characterise the soil hydraulic properties. Particularly the soil–water retention
relationships were measured by means of a low– and a high–pressure Richards’ apparatus,
and the hydraulic conductivity at saturation of each soil layer was estimated by
2–dimensional, axis–symmetrical, inverse modelling of field infiltration tests from single ring
infiltrometer.
The measurements were performed during Summer 2012 and Summer 2013. The
groundwater exchange was numerically estimated both in wet (Summer 2012) and in dry
meteorlogical conditions (Summer 2013). Evapotranspiration was assessed by means of
Penman–Monteith method, which was found to be in the range between EC–estimated
fluxes and an indirect estimate based on the Bowen ratio correction for Summer
2012.
The two seasons are meteorologically very different and it results also in the soil–water
regime. During Summer 2012, the weather was relatively wet, the soil did not reach very
small water contents, so that precipitation was able to percolate towards the groundwater
table and the groundwater table to meaningfully contribute to the evapotranspirative fluxes.
Summer 2013 was instead much drier, precipitation was not able to meaningfully change the
water content of the lowest soil layer and to percolate toward the water table. As a
consequence of the very small water contents of the soil, also a very small water rise had
place. |
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