Vízügyi Közlemények, 1970 (52. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

vestigation into a case where changes in the sediment conditions downstream of a power station greatly contributed to the power development of a river. This paper presents a striking demonstration of the special problems of river regulation which may arise in connection with a particular use of water. The new demands on river regulation cannot be met, however, unless the engineers are prepared for their varied tasks, as pointed out by J. Szilágyi [17]. during the discussion of the paper at the Hungarian Hydrological Society. He suggested that this need for preparation appears equally in the fields of hydrology and hydraulics, construction activity and in the analysis of economic problems. In dealing with the papers submitted to the symposium on the subject of modern principles and methods of river regulation — which is the first subject of the Symposium — these will be considered expediently according to the above three groups. 1. Problems of hydrology and hydraulics Before considering the modern principles of river regulation a better understanding of the basic objectives thereof is deemed desirable. Although various investigators agree fairly well on this subject, a brief comparison appears to be of interest. In their collective paper, Bognár, Hernády and Ivicsics [2] express the opinion that the basic aim of river regulation is always to meet a fundamental social objective, be it of economic, public health, aesthetic, or other character. The engineering objectives are no more than means of achieving this objective. The development of the channel is regarded as a selfcontrolled process by Karaushev [7], where regulation is effected through the sediment transporting capacity of the watercourse. The trend of this process — aggradation, degradation, or the condition of a dynamically stable channel —• is controlled by the relationship between the rate of sediment transportation and the sediment transporting capacity of the watercourse. In the paper a dynamic grouping and classification of the river bed is suggested, and four basic types are established. The objective of river regulation may be defined, obviously, as the effort towards creating the conditions of dynamic equilibrium, i. е., the basic channel type No. 4 on river showing a degrading, or aggrading tendency (basic types No. 2 and 3, respectively). Vershbitzky [14] suggested as a primary requirement in dealing with regulation problems, the observation of the natural conditions of the bed, which should be changed only to an extent not to disturb the dynamic stability of the channel. Garbrecht and Holtroff [4] define the objective of river regulation as the determination of the alinement in plan, the cross-sections and slope of the watercourse in a manner to create stable conditions (regime), satisfying at the same time the engineering requirement (navigation, intakes and diversions, passage of flood flows) as well. 30