Vízügyi Közlemények, 1970 (52. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

It is generally recognized that sediment transportation is largely governed by bed configurations. Although in river regulation mezo-configurations extending to individual cross-section and macro-configurations characteristic for longer stretches play the decisive role, when considering the physical aspects of the phenomenon the study of micro-configurations becomes also inevitable. The third trend of investigations is not of recent origin. In all studies connected with river regulation and fluvial hydraulics, attempts have been made from the very beginning to check theoretical results against the data of field observations. A novel feature in the comparison of theory and experience is, however, that the correlation is extended to all aspects of sediment transportation and that it is performed systematically. In trying to correlate theoretical results and field observation data, additional unsolved problems arise inevitably. This circumstance should not be regarded as an obstacle to this work, since as revealed by the latest investigations, various sediment transportation phenomena are interrelated much more closely than believed earlier. The theoretical conclusions are thus interrelated and although particular problems are solved for convenience independently and gradually, it is imperative to co-ordinate and check them continuously. While recognizing, and approving of the recent trends of investigation mentioned above it is deemed advisable to place special emphasis on a jew particular problems. One of the most important tasks appears to be the introduction or even obligatory performance of sediment observations on a routine basis. One of the objectives in sediment observation should be the development of an organized and regular observing, data collecting and processing system which has been realized for instance in hydrometry by practically every country. A more extensive study of bed configurations is felt to be necessary since, besides the general hydraulic properties of watercourses, these are of decisive influence of sediment transportation and, in turn, on bed development. Further investigations are necessary to make the determination of rates of sediment transportation accessible for practical work. It has become imperative to review and check the great number of sediment discharge relationships. Methods must be developed by further research which are theoretically well founded and guarantee at the same time that they yield the actual rate of sediment transportation under the conditions of a particular watercourse. More extensive application and use should be made of the possibilities offered by various tracer materials. The experimental use of these has already yielded many valuable results. Tracers may be expected to provide information on additional details of this highly complex physical phenomenon. 25