Vízügyi Közlemények, 1970 (52. évfolyam)
4. füzet - Rövidebb közlemények és beszámolók
U is the rate of suspended sediment transportation pertaining to a particular discharge (kg/sec), Q is the discharge passing the gaging section under consideration (cu.m/sec), Q a is the annual average discharge passing through the gaging section under consideration (cu.m/sec), G a and U a have been defined in connection with Eq. (1). d) The ratio of quantities G a/G„ + U a computed from Eq. (1) and obtained by field observations provides information on the equilibrium conditions of the stream section under consideration. The rate of bed-load transportation is, however, only one of the characteristics of sediment transportation and consequently of bed changes. A great number of other quantities must also be known to gain better insight into the process of bed-development. Observation of the changing values of the many variable factors are extremely time and money consuming. This is one of the reasons for our lack of knowledge in many aspects of the process of bed development. The considerable length of time and volume of work required for processing the data once obtained may be regarded as another reason. Attempts at overcoming these difficulties are described in the report by H. Hinrich [4]. By mechanizing observation and data processing work, as well as by the application of suitable instruments and devices for observation, the number of observation and processing personnel can be reduced materially together with the potential sources of error. Many of the ideas contained in the paper of H. Hinrich are interesting enough to be taken into consideration during the development of the hydrological observation network in Hungary, as well as in the processing and evaluation of hydrological observation data. Studies into the movement of sand-bars contribute much to our understanding on the bed forming influence of bed-load transportation. Interesting data, results and conclusions have been added to the knowledge of sand-bar movement by N. S. Znamenskhaya [6], who distinguished 7 different sand-bar types. In the paper a relationship is presented j between the velocity of sand-bar travel (C r), the value — and the Froude A number ^Fr = y^pj j ^ suggested further to create within individual language territories a uniform, exact terminology for the concepts associated with the morphology of rivers and to adhere to these definitions and terms in all publications. A phenomenon rarely observed in Hungary is where the amount of solids carried by water is too high to be considered sediment-laden water any more. In this special case mud is flowing over the terrain, or in the bed. The physical properties and characteristics of this liquid mud are considered by I. I. Herheulidse [5], who determined the greatest possible concentration of solids in similar mud flows. 63
