Data di Pubblicazione:
2008
Citazione:
The importance of observations on fluxes to constrain ground water model calibration / C. Vassena, C. Durante, M. Giudici, G. Ponzini. - In: PHYSICS AND CHEMISTRY OF THE EARTH. - ISSN 1474-7065. - 33:17-18(2008), pp. 1105-1110.
Abstract:
The aquifer system in the alluvial basin bordered by Adda, Po and Oglio rivers (Northern Italy) is characterised by a dual flow regime.
In shallow sediments, which constitute a phreatic aquifer with high conductivity, great fluxes are driven by the interaction between
ground water and the network of surface water, by the infiltration of rain and irrigation water, and by the fluxes drained from depression
springs and river valley terraces. The underlying semiconfined aquifers are characterised by minor fluxes driven by water abstraction
from wells of the public Water Works. Since most of the ground water flow occurs in the phreatic aquifer, an equivalent single layer
2D steady state flow model has been calibrated. The identification of the transmissivity field at the scale of the model has been obtained
by solving an inverse problem with the comparison model method which requires an initial configuration, i.e., reference head, initial
transmissivity field, source terms. Most of the head and source data are related to the phreatic aquifer, but most of the estimates of transmissivity
are obtained with field tests conducted in deep wells pumping from the semiconfined aquifers, so that this kind of prior information
cannot be used directly for model calibration. The inverse problem is underdetermined and a unique solution is not available.
Furthermore information on surface hydrology is poor. Therefore many tests with different hypotheses about the initial configuration
have been performed and some of them have been selected and used to initialise the automatic inversion procedure.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
C. Vassena, C. Durante, M. Giudici, G. Ponzini
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