The problem concerning compulsory introduction of safety certificates for water-development works [1] that had previously not fallen under the safety-declaration procedure in conformity with resolution [2], as a result of which a significant volume of information on the status of water-development works that are potentially capable of causing an extreme situation, has been hidden from the attention of inspection agencies and directors of municipal education regarding subjects of the Russian Federation, is particularly urgent at the present time. In the majority of cases, numerous (of the order of 30,000 – 40,000) Class-III and -IV hydroprojects are such entities. One of the principal problems relating to the compilation of safety certificates is the determination of a zone of a possible extreme situation (flooding zone), amount of destruction, and number of victims. To determine a zone of possible flooding and damages due to a flood caused by breach of the thrust front of a hydroproject, it is necessary to establish and model a scenario for the emergency. Modeling of a breach flood is a complex multiple-factor problem. The original disturbances that had caused the emergency, characteristic design features of the hydroproject, the geologic conditions of the region, petrological factors, the conditions under which the land is utilized for agriculture in the tail race, etc. may exert a significant influence on the path of the emergency. As a rule, the paths of breach floods are investigated using oneor two-dimensional St. Venant equations [3, 4], which can be numerically realized by use of a finite-difference scheme. One of the most familiar finite-different schemes in Russia is the scheme developed by A. N. Militeev [5]. The scheme permits analyses in channels of arbitrary shape and with virtually arbitrary unexpected changes in the shape of the channel, as well as in initially dry channels. The procedure has been put through detailed testing by comparing results of calculations with a large number of analytical tests [6 – 8]. The testing has demonstrated that it permits calculation of flows with hydraulic jumps, bores, and critical sections. The “SV 1” program developed by S. Ya. Shkol’nikov, and also the “Bor” and “River” programs developed by V. V. Belikov implement Militeev’s scheme. In addition to developments of Russian scientists, their are a number of foreign methods of determining the parameters of a breach wave, which are based on similar analytical principles, for example, the “Mike 11” program developed in Denmark. Computer-assisted solution of similar problems requires a highly qualified engineer to perform the analysis, the investment of significant monetary resources, and the existence of a sufficiently well equipped computer laboratory in connection with the fact that similar calculations are, as a rule, performed for high-head hydroprojects falling under the mandatory procedure of the safety declaration. In addition to precise numerical methods that are implemented with a computer, there are also other methods of analyzing a breach wave. B. L. Istorik’s grapho-analytical procedure, which is compiled on the basis of study of breach waves using hydraulic and mathematical models was the first serious study in this field. Broad numerical experiments for schematized conditions and full-scaloe entities have made it possible to obtain a large amount of factual data, on the basis of which general laws and certain characteristic features of the propagation of a breach wave under various conditions have been revealed while making use of methods of the theory of dimensionality and similarity. All this has served as a base for development of simplified grapho-analytical procedures suitable for comparatively rapid preliminary estimation of breach-wave parameters, and also for final prediction of its parameters in certain less critical cases. Being simplified, B. L. Istorik’s procedure unconditionally possesses a number of restrictions. Among other things, it does not permit calculation of the aftereffects of emergencies in the case of cascade failure of hydroprojects, since there is no calculation for the case of a hydrostatic head in the tail race from a dam situated downstream. This procedure is distinguished, however, by considerable simplicity of analPower Technology and Engineering Vol. 44, No. 2, 2010