flow within the embankment was anticipated. Such unconfined seepage flow is typically a boundary value problem, whose seep-age boundary is unknown and has to be determined as part of the solution (Cividini & Gioda (1984), Desai & Li (1983) and Bathe et al. (1982)). The phreatic surface that develops within the em-bankment 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 “exported” to a related software called SLOPE/W so that stability of the em-bankment shoulder can be assessed.