Présentations Colloques

Oral Presentation
8.10
Session 8.10: Recent developments in groundwater modeling and mathematical tools in Hydrogeology
Zech Alraune
Flow-adapted parametrization of subsurface heterogeneity - Estimating aquifer statistics from transient pumping tests
A novel concept is presented for interpreting transient pumping tests in heterogeneous transmissivity fields to infer the geostatistical parameters of the medium. The methodology bases upon the upscaling method Coarse Graining which provides a theoretical framework for a flow-adapted parametrization of subsurface heterogeneity. Simply expressed, the heterogeneity of transmissivity is filtered according to the characteristics of well flow tests. The filter is chosen small in the vicinity of the pumping well and increases with increasing distance. The application of the concept to well flow - called Radial Coarse Graining - provides an effective description of transmissivity for pumping tests in heterogeneous media. It was used to derive an Effective Well Flow Solution for transient flow conditions including not only the parameters storativity, but also the geometric mean, the variance, and the correlation length of log-transmissivity.**Parameters of aquifer heterogeneity, in particular variance and correlation length, can be inferred from simulated pumping test drawdowns by combining the Effective Well Flow Solution with inverse estimation techniques. A sampling strategy - comprising pumping tests at multiple locations within an aquifer - is presented in order to show that the parameters of aquifer heterogeneity can be inferred under field conditions. Pumping test field data is analyzed in the same procedure, showing promising results in comparison to other geostatistical methods for aquifer analysis.**
Germany