The purpose of this study was to analyze the capacity of the reservoir to the change in land use around the Unnes campus. The research method used is the flood hydrograph routing method in the reservoir using the Storm Water Management Model (SWMM) program to obtain the maximum capacity of the reservoir flood discharge, after which a comparison of the planned flood discharge of the resevoir to the flood discharge in the existing conditions of the reservoir is carried out to assess the capacity of the Unnes reservoir against land use change. Based on the results of the study, it was found that there was a change in the bottom depth of the reservoir at the beginning of the planning was 4.00 meters and in the current condition it became 3.00 meters, which means that the capacity is reduced by 1.00 meters with the ability to pass the flood discharge inflow which is still adequate and there is no overflow of flood.