Calibration and Reliability in Groundwater
Modelling: Credibility of Modelling
(Proceedings of ModelCARE 2007 Conference, held in
Denmark, September 2007). IAHS Publ. 320, 2008, 316-321.
Data error and
highly parameterized groundwater models
Mary C. Hill
US Geological Survey, 3215 Marine St,
Boulder, Colorado 80303, USA
Abstract
Strengths and weaknesses of highly parameterized models, in which the number of
parameters exceeds the number of observations, are demonstrated using a
synthetic test case. Results suggest that the approach can yield close matches
to observations but also serious errors in system representation. It is
proposed that avoiding the difficulties of highly parameterized models requires
close evaluation of: (1) model fit, (2) performance of the regression, and (3) estimated
parameter distributions. Comparisons to hydrogeologic information are expected
to be critical to obtaining credible models.
Key words calibration; parameterization; optimization; pilot points; uncertainty