3-D Groundwater Modeling for Litigation

The challenge:

ES&T, a division of GES, performed a comprehensive assessment of solvent impact to groundwater for three communities covering an area of 200 square miles, for a nationally-recognized litigation case. Solvent source areas included waste lagoons, dry wells, and septic fields. Water cascading down the production well bores from perched aquifer systems created complex contaminant distributions. ES&T used three-dimensional calibrated groundwater flow and solvent transport modeling to accurately simulate groundwater flow conditions.

The GES solution:

ES&T calibrated groundwater flow models to 35 years of historical water-level elevations, groundwater gradients, and aquifer water balance conditions. Recharge estimates from land use and ground cover were derived from geographic system analyses of the study area. Close to source areas, leakage from unlined canals significantly altered local groundwater flow fields. ES&T researched facility invoices and interviewed facility personnel to evaluate source volumes and releases. Concentrations observed at wells over time were compared with calibrated values. For the production wells, flow-weighted averages were calculated due to the high pumping rates and long well screens in these wells.

The benefits:

Animations were developed from the calibrated model results and submitted as exhibits for the plaintiff in property damage trial proceedings. Visualizations made communication of complex issues understandable to a non-technical audience.