The storage capacity of reservoirs is gradually depleted due to sediment accumulation that causes changes in the area-storage capacity curves (ASC). These curves are important for planners, designers and operators of dams. Many empirical and semi-empirical approaches have been suggested for establishing and predicting these curves. In this study four empirical and semi-empirical methods were evaluated and used to determine the ASC curves for Mosul dam reservoir (MDR), which is the biggest hydraulic structure on the River Tigris in northern Iraq. MDR started operating in 1986 with a storage capacity of 11.11 km3 and a water surface area 380 km2 at normal operation stage (330 m a.s.l.). The results obtained from these methods were evaluated using observed bathymetric survey data that had been collected in 2011 after 25 years of the operation of the dam. The evaluation results showed three methods presented more accurate results for estimating water depth or sedimentation depth at dam site with percentage error about 1.06% to 3.295%.