Translated from Gidrotekhnicheskoe Stroitel 'stvo, No. 10, October 2012, pp. 26 -29. The effect of constraints placed on rate of change of water level in a reservoir on the power-generating performance indicators of a hydroelectric power plant, for example, the Sayano-Shushenskaya HPP, is examined. Variation in power-generating performance indicators of the Krasnoyarsk HHP is determined with use of these constraints placed on the Sayano-Shushenskaya HPP.The safety of water-development works (WDW) of a hydroproject, the population and agricultural entities situated downstream, and the surrounding environment, as well as the operational reliability of the power-generating entity, are determined largely by utilization of the water resources in the reservoir.A characteristic of the dynamics of the change in the water level within the reservoir -the rate at which the horizon ascends or descends in a design time interval on the dispatcher's chart -has gone unregulated. This characteristic, however, assumes importance and frequently decisive significant for the safety of water-development works.Fluctuations of the water level of the reservoir during its service are accompanied by reconfiguration of the stressstrain and filtration states in the mass of the bed. Zones of excess pressure in which failure processes of the mass evolve, may develop during rapid drawdown of the reservoir. Moreover, failure will occur due to intergrowth of large permeable cracks, whereas the concentration of fine cracks remains as before [1]. Also, rapid filling or drawdown of the water level may have an unfavorable effect on the position of the depression curve of an earth-fill (hydraulicked) dam and the banks, resulting in diminution of the safety of the WDW.As a result of manifestation of phenomena exerting a negative influence on the safety of the WDW, the need has arisen for use of certain constraints on the operating regime of the reservoir.It should be remembered that in analyzing the passage of maximum flow rates with a design probability exceeding the limitation placed on the rate of filling of the reservoir, however, these constrains have not been expanded to cover the entire year.Use of constraints on the rate of change of the water level in the reservoir will effect a change in its operating regime, and as a result, a change in the operating regime of the hydroelectric power plant [2]. In turn, a change in the operating regime of a power plant located upstream on the river may influence operation of plants residing downstream. This paper examines the effect of limitations placed on the rate of change of the water level in the reservoir on the power-generating indicators of the plant's performance as exemplified by the Sayano-Shushenskaya HPP, and also evaluates the consequence of use of this constraint on similar performance indicators of the Krasnoyarsk HPP.In addition to flow regulation preferentially for purposes of power generation, the Sayano-Shushenskaya hydroelectric complex is used for demands of water transport, communal...