Sedimentation in dams' reservoirs is one of the most pressing concerns facing dams today. Maroon reservoir dam, located in Khuzestan Province, is one of the most important dams in this region. Since it is a new constructed dam, numerical simulation of sedimentation trend in its reservoirs could significantly help on a better utilization. To this end, TCM model which is capable to simulate density currents was used. The obtained results show that the dam loses about 91 million m3 of its reservoirs during a 50-year exploitation period.