Despite the practical limitations of calculating the amount of inflow and supply related to the operation of agricultural reservoirs, the role of agriculturalreservoirs is gradually being emphasized. In particular, as interest in disaster safety has increased, the demand for preliminary measures to prepare fordisasters has been rising, for instance, pre-discharging agricultural reservoirs for flood control. The aim of this study is to analyze the plans for theflood season reservoir operation considering pre-discharge period and water level limit. Accordingly, we optimized the simulation of daily storage usingthe ratio correction factor (RCFs) and analyzed the amount of inflow and supply using K-HAS. In addition we developed the drought determinationcoefficient (k) as a indicator of water availability and applied it for supplementing the risk level criteria in the Drought Crisis Response Manual. Theresults showed that it would be difficult to set the water level limit during the flood period in the situation of little water supply for flood controlin agricultural reservoirs. Therefore, it is necessary to operate the reservoir management regulations after measures such as securing additional storagewater are established in the future.