Calibration and Reliability in Groundwater Modelling: Credibility of Modelling

(Proceedings of ModelCARE 2007 Conference, held in Denmark, September 2007). IAHS Publ. 320, 2008, 331-336.

Conceptual uncertainty assessment for a catchment scale model

Matej Gedeon & isabelle wemaere

Belgian Nuclear Research Centre, Boeretang 200, B-2400 Mol, Belgium

matej.gedeon@sckcen.be

Abstract A groundwater flow model of the Neogene aquifer system, representing an important water supply resource, has been developed within the performance assessments studies of a geological disposal of radioactive waste in Belgium. In order to evaluate the discrepancy between an estimated parameter and a measured value of the Kasterlee Clay aquitard, uncertainty analyses were applied on three aspects of its conceptual model. These analyses included the parameterisation, geometry (thickness) of all units and the geometrical representation of the Kasterlee Clay. The results of the analyses showed that the conceptual model of the Kasterlee Clay should be reconsidered, allowing less resistance of the unit locally. To identify such places, further site investigation is recommended.

Key words groundwater flow; inverse modelling; conceptual model; uncertainty