Vízügyi Közlemények, 1974 (56. évfolyam)

1. füzet - Kovács György: A felszíni lefolyás általános vizsgálata és az árvizek előrejelzése

A felszíni lefolyás vizsgálata 51 РАНТ I General study of surface runoff 1. Determination of the effective rain The studies included in the analysis reflect positively the correct endeavours to express the relationship between rainfall and surface runoff in the form of a difference, rather than that of a ratio. This means that the runoff coefficient must be discarded in favour of the rainfall excess running off the surface. The solution was sought thus far by analytical methods, striving for a direct relation between the input (rainfall) and the output (runoff volume). The objective to be identified for the future is thus the determination of effective precipitation by a method of synthesis, i. е., by the physical analysis of the phenomena predominating in the process and by relating the parameters affecting these to regular observation data. For this purpose it is necessary to consider first the distribution of precipitation vertically and over the area alike. In this respect the results attained here first of all in the determination of structural functions of precipitation, further of the spaceand time scales of diverse types of rainfall activities are recognized internationally. It should be noted that the determination of rainfall distribution over the area is considered essential by various international scientific organizations as well, so that improving the results attained thus far it is warranted to continue intensively the hydrometeorological investigations that furnish the data necessary for liydrological research. The exploration of the relationship between radiation and potential evaporation, moreover the forecasting of expected evaporation influenced by radiation appear also as a research demand in meteorology, or hydrometeorology. It has been suggested that at times of rainfall the heat quantity incorporated by the advancing air masses can be related to actual evaporation during the rainfall. This idea seems interesting enough to warrant a more detailed study. Little attention has been devoted thus far to the important parameter of interception. For a belter understanding thereof the collation of research advances abroad and of data of scattered observation in Hungary is recommended as a first step. The correctness of the mathematical model outlined in the paper can be checked against these and the parameters thereof could be determined from them. For completing the data that can be made available and for perfecting knowledge of the entire cycle, further for checking the reliability ol' the relationships formulated, additional observations are suggested. Exploration of the infiltration process, which is responsible for the greatest part of the difference between full- and effective precipitation, is finally identified as one of the most important tasks of the future. Interesting results have been attained in recent years both in the field and at the laboratory at diverse research stations in Hungary. It should be realized, however, that the empirical relations, as well as the theoretical formulae derived by combining the continuity and dynamic equations, and by introducing simplifying assumptions must be regarded as first approximations only. A complete solution cannot be expected, unless the liydrological processes taking place in the three-phase zone are explored in every detail. Research in this direction has been started under international cooperation, with Hungarian scientists coordinating this work. This enterprise should therefore be attributed outstanding significance. 2. Studies on the surface accumulation process Hungarian scientists have attained interesting results in both branches of systems analysis and in constructing the models thereof, namely the analytical and synthetizing models. This approach is presently regarded most effective in liydrological research. This is completed to advantage by adapting the models conceived abroad. Further work in each of the three.directions of research is fully warranted. In the domain of analytical models the search for multi-variable relations, while in synthetizing studies the exploration of the dominant physical processes appear 4*