Along with the rapid development of the city of Semarang, numerous problems have emerged, including the occurrence of flood-related natural disasters in several areas along the city's north coast, one of which is the flood. The flow of the Babon River, a component of the East Semarang drainage system, stretches from the Penggaron region in the upstream to the Genuk region in the downstream..Numerous factors affect the Babon Semarang River, including its restricted capacity due to sedimentation, the pace of land subsidence, high tides, and overflows from nearby rivers. This regulation is for figuring out how high the water will get during the rainy season, how much water the river can hold using Hec-ras, and how to handle the Babon river flood. Research Techniques for the Analysis of the Babon River Flood Control in the Karangroto-Banjardowo Area, Semarang City, starts with the gathering of secondary data, such as data on rainfall, data from rain stations, and data on the characteristics of watersheds.Using information on rainfall, channel measurement data, and the state of the channel, the planned flood discharge (R24) is calculated.The researcher will use this information to determine the anticipated rainfall for the return periods of Q 2, 5, 10, 25, 50, and 100 years.We employ the Normal Distribution, Log Normal Distribution, Pearson III Log Distribution, and Gumbel Distribution to calculate the data. Afterward, Log III distribution analysis was used since it was closer based on these calculations. he peak flood discharge (QP) value is 2.07 km³, the Q2 year is 21.82 m/sec, the Q5 year is 25.17 m/sec, the Q10 year is 27.41 m/sec, the Q25 year is 30.25 m/s, the Q50 year is 32.40 m3/s, and the Q100 year is 34.55 km³/s, according to data analysis using the Nakayashu method.Following that, it is simulated in the Hydrology Engineering Center River Analysis System (Hec-Ras) application program using the flood discharge data for the Q50 year return period.