The peak of 1,000 years flood in the catchments of Keng Seuaten Dam is about 5,347 m3/s. The study of flood routing through the spillway indicates the maximum flood level at + 489.39 m. ms. when the full supply level is +485 m msl, So the full supply level in the reservoir should not exceed level +485 m msl. This level is defined as a maximum allowable full supply level