Transport upscaling in highly heterogeneous aquifers and the prediction
of tracer dispersion at the Macrodispersion Experiment (MADE) site
Abstract
We present an upscaled Lagrangian approach to predict the plume
evolution in highly heterogeneous aquifers. The model is parameterized
by transport independent characteristics such as the statistics of
hydraulic conductivity and the Eulerian flow speed. It can be
conditioned on the tracer properties, the conductivity data at the
injection region, and is able to account for mobile-immobile mass
transfer. Thus, the model is transferable to different solutes and
hydraulic conditions. It captures the large scale non-Gaussian features
for the evolution of the longitudinal mass distribution observed for the
bromide and tritium tracer plumes at the macrodispersion experiment
(MADE) site (Columbus, Ohio, USA), which are characterized by a slow
moving peak and pronounced forward tailing. These large scale features
are explained by advective tracer propagation due to a broad
distribution of spatially persistent Eulerian flow speeds as a result of
spatial variability in hydraulic conductivity.