Vízügyi Közlemények, 1994 (76. évfolyam)

1. füzet - Goda László: Tározók árvízcsökkentő hatásának számítása

Ifj. Goda László 103 IRODALOM Hukovszky Gy.: Kisvízfolyások árvizeinek tarozása. Vízügyi Közlemények,1965/1. Dum. T. -Knoblauch. H.-Medved,N-Stranner. H.: Hochwasserrückhalteanlagen inderSteiermark. (Árvízesökkenlő tározók Stájerországban). Amt der Steiennarkisehen Landesregierung, Fachabteilungsgruppe Landesbaudireetion, Fachabteilung III.a - Wasserwirtschaft Gálái A.- Zsuffa /.: Reservoir Sizing by Transition Probabilities Water Resources Publications, 1987 Littleton, Colorado, USA Kontur 1,- К oris К - Winter J.: I lidrológiai számítások I., II. Kézirat, Tankönyvkiadó, Hp., 1980. Mohos О : Tározók árhullámcsökkentő hatásának vizsgálata Sorrensen eljárása szerint. Műszaki segédlet, Győr, 1964. Zsujfa /: Tározóméretezés matematikai statisztikai eszközökkel VGI-PMMFVízgazd. Int., Bp.-Baja, 1981. •jf * * Calculating the flood-alleviating effect of reservoirs by László CODA. C.F.. junior The flood control capacity of reservoirs built for the purpose, or utilized for this purpose too, can be expressed by Equation 1. (Figure 1). Flood control reservoirs can be grouped into three categories ( Figure 2), on the basis of their operation rules. The author seeks a generally applicable solution for the numerical determination of the floodcontrol capacity of reservoirs built for the purpose or of multi-objective use. The discretized version (Eq. 9) of the differential equation of storage (Eq. 2) is utilized for the development of a computer model which routes the fate of water throughout the whole storage process and calculates the flood hydrograph released by the reservoir for any reservoir operation rule. Figures 3-6 show the released, downstream, Hood hydrographs for a design Hood ( p—

0.5% probability of cxceedance, with peak How of 137 m

3/s) and for various spillway and operation parameters ( Table I). For constructing the characteristic capacity curves of Eq. 1 data of the peaking value of the outlet hydrograph and of the maximum storage volume are needed. Results of the calculation with the unified model are shown in Figure 7 for the three basic storage models. The author investigated the effects of two parameters of reservoir dimension and operation simultaneously. The example shown in Figure H is based on two variables;- the size and crest elevation of the spillway weir. It is assumed that at the commencement of Hooding the reservoir is full, that is the initial reservoir level is the crest level of the spillway, and there is no release through the outlet structure, 'flic example shown in Figure 9 corresponds to a similar case, with the exception that there is a constant flow release of 60 m/s through the outlet structure. Figure 10 shows an example of the simultaneous analysis of the case of several floods of varying probability of occurrence. Other parameter of the model is the elevation of the spillway crest and the computation starts again with the reservoir level matching the crest elevation. The model described in this paper is suitable not only for the transformation of a single flood hydrograph. but can also simulate the actual operation of the reservoir using any arbitrarily selected time series of inflow. The result of this calculation is the transformed time series of discharge downstream of the dam. This time series can be evaluated by the means of mathematical statistics. Figure 1 ! shows the Gumbel distribution curves of the annual maximums of upstream and downstream flow lime series simultaneously, for wide-crested spillway widths of 20m, 10m, and 5m. In this example the simulation started with the assumption of full reservoir and without operating the bottom outlet structure. If in critical periods forecasting of inflow to the reservoir is possible using