As the sand-fill was hydraulically placed, an unconfined seepage flow within the embankment was anticipated. Such unconfined seepage flow is typically a boundary value problem, whose seepage boundary is unknown and has to be determined as part of the solution and Bathe et al. (1982). The phreatic surface that develops within the embankment during hydraulic sand-filling can be modelled using a commercially available software called SEEP/W. Once the phreatic surface has been determined, it may then be "exporter" to a related software called SLOPE/W so that stability of the embankment shoulder can be assessed .