Calibration and Reliability in Groundwater
Modelling: Credibility of Modelling
(Proceedings of ModelCARE 2007 Conference, held in
Denmark, September 2007). IAHS Publ. 320, 2008, 39-44.
Characterizing the
spatial variability of transmissivity using stochastic type-curve and numerical
inverse analyses of data from a sequence of pumping tests
MONICA RIVA1, ALBERTO GUADAGNINI1 & SHLOMO P. NEUMAN2
1 DIIAR, Politecnico di Milano, Piazza L. Da
Vinci 32, Milano 20133, Italy
2 Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona 85721, USA
Abstract We discuss two recent methods of characterizing the spatial variability of a random (natural) log transmissivity field on the basis of observed space–time variations in hydraulic head: a graphical stochastic type-curve method and a geostatistical method of inverting (ensemble) mean flow equations. While both methods allow estimating the unconditional variance and integral (correlation) scale of log transmissivities, geostatistical inversion is computationally more intensive, but also provides tomographic images of how log transmissivity estimates and their variance vary in space. We apply the two approaches to synthetic scenarios and to measured late time (quasi-steady state) drawdowns from a sequence of transient pumping tests in an unconfined aquifer near TŸbingen, Germany.
Key words stochastic inverse models; geostatistics; pumping tests; type curves