Valparaiso, Indiana:
Modeling Chloride Contamination

Operation of a salt handling facility has resulted in the contamination of the aquifer below the facility with high levels of sodium and chloride. The main concern at this facility was the proximity of a municipal supply wellfield, located about 1,700 feet north. Groundwater monitoring has confirmed the movement of salt at the base of the aquifer toward the wellfield.

Diagram of Valparaiso Chloride Plume

(Click image for larger view)

Groundwater modeling was done at this site to aid in the design of remedial alternatives. Initial model calibration involved the use of a single-phase flow model. The flow model was calibrated to steady-state and transient conditions. A 2-phase, sharp-interface model was then used to simulate the historical migration of a dense salt plume at the base of the aquifer beneath the facility. Concurrently, a solute transport model was linked to the transient simulation. The solute transport model was used to simulate the dispersive movement of salt from the dense phase plume into the surrounding aquifer. The sharp-interface model was used to simulate salt migration over the 30 year operational period of the facility.