This training manual is a short course of basics and practical calculations of river flow regulation for water supply, irrigation, hydropower, thermal power plants and other water users. The calculations of the main parameters of reservoirs are covered, the rules for managing their work with the most appropriate use of runoff are given (according to dispatch schedules). The influence of changes in hydrological parameters on the yield of reservoirs is considered, the principles of flood and flood regulation are set out. To replace complex and time-consuming calculations, the calculated graphs and tables . are given. Practical approaches for the operation of reservoirs with the use of various types of river flow regulation are presented.