In this research, an analytical study was conducted of the Wadi Rabia stream and the spill basin that feeds it, especially at the intersection of the main stream stream of Wadi Rabia with the international road (Homs-Damascus) in the Hasiya area. The basin was drawn using topographical maps of the research site, after obtaining the necessary data from the climate station closest to the study site (Sadad Station), where the area of the basin was about 615 km2. The maximum daily rainfall with a probability of 1% was approximately 47 mm/day, and the maximum discharge was approximately 250 m3/s according to the statistical method. The results of the expected maximum daily precipitation values were compared using 4 internationally known distributions: Gumbel-Foster1-Foster-3-Pearson, where the values ranged between mm/day (49-55), and the Gumbel method gave the highest value than the other distributions.