Statistics for The effect of subsurface barrier on the motion of the sea water—fresh water interface in coastal aquifers is analysed for sudden freshwater drawdown conditions. A Galerkin finite element model is used for this purpose to carry out the parametric studies of the effect of location, width and hydraulic conductivity of the barrier. The results indicated marked variations in the interface profile as compared to no barrier condition. The width and hydraulic conductivity play a decisive role in delaying the interface response for any drawdown situations. Among the various barrier locations considered, the barrier at initial length of intrusion L0 was found to be most effective in checking the salt water intrusion. © 2002 Taylor & Francis Group, LLC.