Diesel migration in sand under groundwater movements

This research experimentally investigates the effects of groundwater movement on the migration of diesel in the subsurface. One-dimensional column test is used to study the effects of groundwater level fluctuation. Two-dimensional tank test is used to study the coupling effects of groundwater level fluctuation and horizontal groundwater flow. The Simplified Image Analysis Method is used as a non-intrusive and non-destructive technique to measure temporal and spatial distribution of fluid saturations in a whole domain. The results show that the water table fluctuation significantly affects the LNAPL distribution in the ground to the full range of the water table and capillary fringe fluctuating zones. A higher rate of horizontal groundwater flow also results in a larger area of diesel contamination. Contaminants can be displaced upward and/or emerge above the soil surface under the vertical groundwater flow; therefore, the secondary infiltration effect on LNAPL contaminants needs to be considered.