In this paper, an analysis of the hydrograph of runoff, and hydrograph analysis with theoretically approach the process of runoff on the section of the river that is constrained downstream of the dam. The introduction presents a description of the hydrology, its basic objectives and processing hydrological data. The theoretical part is described hydrograph with its basic characteristics. The description of separating direct from the base flow, unit hydrograph and what affects their appearance. Solution to the problem that provides analysis Runoff hydrograph on the section of the river on which it is made hidrometric measurement. Is defined by the ratio of water levels and flow and konsupciska curve, and have certain characteristics flood wave such as rise time, decay and base hydrograph and the maximum average flow and volume of flood wave.