Transport Upscaling in Highly Heterogeneous Aquifers and the Prediction of Tracer Dispersion at the MADE Site.

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 and flow data at the injection region. 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, Mississippi, 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. Plain Language Summary: The prediction of solute transport in highly heterogeneous porous media has been a long‐standing question. We propose an approach that predicts and explains observed tracer distributions in terms of medium and flow heterogeneity. The model is parameterized by the statistical characteristics of hydraulic conductivity, distribution of flow speeds, porosity, and retardation coefficient, that is, transport‐independent parameters. This study gives new insight for the understanding and prediction of large‐scale tracer dispersion in heterogeneous aquifers. Key Points: A predictive model for tracer dispersion in highly heterogeneous aquifers is presentedThe model is parameterized by transport‐independent parametersThe large‐scale evolution of the tracer profiles of the MADE‐1 and MADE‐2 experiments is predicted [ABSTRACT FROM AUTHOR]