Vízügyi Közlemények, 1948 (30. évfolyam)

2. szám - VII. Szakirodalom

(7) с) Reservoir For Total Equalization. Through an increase of the storage capacity, steady and uniform consumption can be enhanced but only up to a certain limit what may be called ideal mean discharge : QuThe ideal mean discharge is the limit of the multi-annual mean discharge, i. e. of the average mean discharge referred theoretically to endless space of time and practically to several decades. Values of the ideal mean discharge defined by Formulae (61) and (62) can be well computed with the graphical method proposed by the. author. The essence of this method is the following: In Formulae (63) and n iki (64) = f (n) n respectively continuous variation of mean value for n years is explained. It is to be plotted in a coordinate-system, and the mutual horizontal asimptote to the covering curves of the line in Figures 48 and 49 respectively is to be drawn. Based on a list of data comprising 42 years for the Visó-River it has been examined: What is the possible limit of deviation in the most unfavourable case between mean values for 10, 15, 20, 25 etc. years on the one hand, and the ideal mean value on the other. From the available 42 year period, a continual period of 10 years can be selected in 33 different ways, a period of 15 years in 28 different ways, etc. With 10 years examined, extreme deviation varies between + 13-0 and—• 14-7%, taking a period of 15 years, the limits of fluctuation are: + 11-5 and — 9-0% and so forth. This kind of examination gives reference also of the shortest period to be taken into consideration when in the computation a given precision is wanted. Figure 50 explains how to make, on the basis of the mass curve, the graphical determination of needed storage capacity to equalize run-off in multi-annual periods. For a steady consumption of the 35-65 m

3/sec ideal mean discharge of the Visó-River, i. e. for total equalization, a capacity of 2680 million m

3 would be necessary. In examination of larger periods the difference between topographical and geographical conditions alike is of a lesser bearing since here the ratio between run-off of both dry and rainy years is dependent primarily on meteorological factors. Consequently the author is of the view that the time dimensional factor: 2680 hm

3 -« hm

3 — -— (6o) r] = = 75 = 75 X 10® sec 35-65 m

3/sec m

3/sec is universally characteristic for each of the Carpathian drainage areas situated in identical climate zones. Accordingly, for any drainage area in the examined regions, necessary storage capacity of a reservoir for total equalization can be computed from the equation: (66) Sq (hm

3) = 75 Q

k (m

3/sec) where Qk means either ideal mean discharge of the drainage area in question, or its approximate value, i. e. the average mean discharge. Table XI proves that topographical conditions in the Carpathian Basin permit development of only annual or multi-annual reservoirs, while that of reservoirs for total equalization is entirely impossible in this area. d) Relation Between Output And Capacity. In Chapters a), b) and с

) some relations between certain values of mean consumption (output) and those of capacity have been laid down. The laws of continual relation have been derived by the author from the aforementioned explanations. This relation may be called storage characteristic of the reservoir (Figure 51.). Computation for the Visó-River of storage capacity adherent to multi-annual periods of different duration has been made with the usual method on the basis of the discharge mass curve for 42 years. The result