Monday, June 23, 2008 : 2:30 p.m.

Multi-Dimensional Marching-Jury Backwards Beam Equation Method with Uncertainty in Transport Parameters

Daniel F. Cornacchiulo, Environmental Assessment and Remediations and Amvrossios C. Bagtzoglou, University of Connecticut

Groundwater contamination in the United States is a growing concern because of the potential risk associated with the contaminants and the extent of the problem. To allocate the cost of remediation activities, forensic techniques (e.g., compositional analysis, tracers, and transport models) are used to identify sources of contaminants. In this paper a backwards in time transport model is studied. The Marching-Jury Backwards Plate Equation method (MJBPE) for a multidimensional problem solves the governing equation backwards in time to determine contaminant source location(s) and historical spatial distribution of a plume(s) in fully heterogeneous media. Two cases were studied to evaluate the MJBPE ability to identify two contamination sources when the plume at the current time is completely mixed and there are no features to distinguish the two different sources. For all cases only the current spatial distribution and limited knowledge of the flow characteristics (dispersion or velocity) are inputted into the model.
The first case assumes that the dispersion coefficient is varying in space and the transport velocities, ux and uy, are constant with the flow being from left to right. In the second case, the transport term is varying in space with the flow being from left to right and the dispersion coefficients, Dx and Dy, are constant.  The objective is to determine the ability of the MJBPE to recover the spatial distribution of the contaminant back in time in a complex heterogeneous medium.
For all 2D cases, MJBPE was able to recover the historical distribution for two contamination sources when a composite plume at the current time is completely mixed and there are no features to distinguish the two different sources. In addition, we intend to apply the MJBPE to a site on Long Island with a detached fuel oxygenate plume to assist in confirming the source.

Daniel F. Cornacchiulo, Environmental Assessment and Remediations Daniel F. Cornacchiulo, Ph.D., Engineer/Hydrogeologist has ten years of experience in the environmental consulting field. Dan’s modeling expertise includes development of a finite-difference computer code for tidal influence on unconfined aquifers. His current research involves numerical modeling of pollution source identification using the Marching-Jury Backward Beam Equation (MJBBE) and the Quasi-Reversibility methods. This research includes stability analysis of the backward methods, applying real life conditions such as sampling densities and uncertainties for the MJBBE. Dr. Cornacchiulo holds a B.A.Sc. in geology from the SUNY Binghamton and a M.Sc. and Ph.D. in Civil Engineering and Engineering Mechanics at Columbia University.


2008 NGWA Conference on Eastern Regional Ground Water Issues