Impact of Human Activity on Groundwater Dynamics (Proceedings of a symposium held during the Sixth IAHS Scientific Assembly at Maastricht, The Netherlands, July 2001). IAHS Publ. no. 269, 2001, pp. 263–269.

Analytical relations between model input statistics and output reliability for verification of a numerical groundwater model

Willem Jan Zaadnoordijk

Hydrology and Ecology Section, Faculty of Civil Engineering and Technical Geosciences,
Delft University of Technology, The Netherlands

e-mail: wj.zaadnoordijk@rtd.iwaco.nl

Abstract Analytical relations between input parameters, output variables and statistics for confidence are derived in order to verify automatic parameter optimization and model reliability packages to be used with a groundwater flow simulation package. The relations are based on the analytical solution for a semi-confined circular island with an extraction well in the centre. Piezometric heads are considered as well as the capture zone of the well. The relations have been used to test the calibration and confidence module TrCalCon of the groundwater flow simulation package TRIWACO. The module allows both linear-variance and Monte-Carlo confidence calculations. The latter show that the nonlinearity of the test problem causes significantly wider confidence intervals in the model results than the output of the former, and is tested with the analytical calculations.

Key words analytic solution; automatic parameter optimization; confidence analysis; numerical model