LNAPL in Variational Hydraulic Gradients and its Impact on Soil Contamination

An investigation was conducted using two-dimensional experiments to evaluate the relationship between LNAPL spill volume, hydraulic gradient, and contamination behaviour.Using a Simplified Image Analysis Method (SIAM) to track diesel migration, the study found that spill volume and hydraulic gradient are the most critical factors influencing a contaminant plume's movement.A larger spill volume, with its greater mass, creates sufficient downward pressure to overcome capillary forces, causing deeper infiltration and bringing the pollutant closer to the groundwater.This significantly elevates the risk of groundwater contamination, especially in areas with fluctuating water tables.Conversely, the hydraulic gradient controls the plume's overall shape and spread.A high gradient leads to a dispersed, widespread plume with a lower concentration at the source, while a low gradient results in a more contained but highly concentrated plume near the spill point.These findings highlight that effective spill response requires an understanding of both the spill's volume and the site's hydraulic conditions.The study ultimately emphasises the importance of early detection and containment to prevent a localised soil contamination event from escalating into a widespread environmental disaster