The increase in peak discharge is caused by changes in land use that occur. This change in land use is due to increasing community needs for housing and infrastructure. The risk of flooding in an area due to an increase in peak discharge. The limited ability of rivers to accommodate runoff will result in river overflows that cause flooding in the area. The Opak watershed is a watershed that is experiencing changes in land use which shows an increase in resilience. Limited data and its partners can make determining flood discharge less than optimal. Snyder SUH is a method for determining flood discharge when experiencing limited rain data and water estimation data. The purpose of this study is to use the Snyder SUH method to determine the peak discharge. The accuracy of the peak discharge results of the Snyder HSS method with unit hydrographs is measured with RMSE. The results of research on the peak discharge of the Opak watershed using the Snyder SUH method were 44.1966 m3/s. The value of the slope parameter or Ct obtained is 1.6, and the value of the watershed characteristic parameter or Cp is 0.16. The accuracy value between the Snyder SUH method and the measured unit hydrograph is 0.077, which can be interpreted as very accurate.