The capacity of each river looks different according to the characteristics of the river. This research was intended to map the appearance capacity of the Winongo River. The river is located in the Province of Yogyakarta Special Region with a river length of ± 35.6 km and upstream in the Kaliurang area and empties into the Opak River in the Kretek area. The method used is by performing an RMA2 simulation on the SMS AQUAVEO 10.1 software with secondary data obtained from the Central Hall of the Serayu River Opak D.I Yogyakarta (BBWSSO-DIY). Data in the form of cross measurement results and Scheme of the Winongo River flood discharge. The modeling results show that Winongo River has different capacities in each segment. The results of the direct discharge on the look were 20 m3/s, 50 m3/s, 67 m3/s, 75 m3/s, 120 m3/s, 140 m3/s, and 150 m3/s. The discharge capacity of the Winongo River approached a 2-year and 10-year return period.