High Resolution Aquifer Characterization - Busting the Grain Size Myth

Abstract:

While major advancements have been made in the field of aquifer characterization, field method development and application for reliable model parametrization and improving system understanding are in many cases yet under-developed. One key parameter for the description of groundwater flow and transport is hydraulic conductivity (K). In every day practice, K is often estimated based on literature values or ex-situ laboratory measurements. The calculation of K based on grain size distribution data is a very prominent example of a well-established but unsuitable method for the characterization of heterogeneous sedimentary deposits. Even though concerns about the suitability of this method for detailed aquifer characterization have been raised in several publications, this approach is still widely used by both, scientists and practitioners – mainly due to its simplicity. Hence, a vast number of different empirical and semi-empirical formulas already exist and even more adapted formulas are proposed, although reliable alternatives are available. With this contribution we want to raise awareness about the intrinsic limitations of using grain size data for the determination of K and show direct push-based alternatives for reliable and efficient high resolution aquifer characterization.