In this paper, pore water pressure in the 15-Khordad dam, an earth fill dam constructed in a V-shaped valley with a clayey core and a height of 96 m was investigated following it's construction. Many vibrating-wire and standpipe piezometers were installed in the body of the dam. Pore water pressure monitoring was made from one week to ten months following the impoundment. The core was modeled by a finite element mesh, and 3-D transient and steady state analyses of pore pressures were performed and the results were compared with the monitored data. The trend in the monitored pore pressure was well modeled by the transient analysis. It was concluded that pore pressures in the cores of embankment dams may not achieve steady state conditions in some months, following the dam construction and impoundment. It was also observed that the selection of conductivity as a function of suction did not affect the results of modeling.