Evolution of a groundwater contaminating plume originating from tar waste - current conditions and remedial strategies. Hydrogeological numerical simulation was performed to evaluate the migration of a contaminant plume at a decommissioned tar manufacturing plant, situated in the floodplain of the Main River, Manitoba. The finite element computer software FEFLOW was used to simulate groundwater flow and contaminant transport. The current mass distribution of the contaminant plume is a result of the historical spills of chemical compounds during the manufacturing process or leaching from the fill materials situated below the former plant and on the riverbank. Based on the characterization and delineation of the impacted groundwater, further simulation was performed to assess the impact of several remedial strategies. Numerical case studies were conducted for each remedial strategy, from which conclusions were drawn regarding the most suitable scenario for the clean-up of the Site. Based on the modeling results, there are currently no chemical compounds at the Site which will result in a future exceedance of the compliance criteria at the Main River boundary if half of the waste fill is removed and backfilled with clean material, while the remaining impacted area is entirely covered at the surface with a low permeability material.