Vízügyi Közlemények, 1948 (30. évfolyam)
2. szám - VII. Szakirodalom
(11) In Table XIV 54 reservoirs are listed according to the respective ß factors after N. KELEN. (Under No. 20 — according to the author's computations — the designed Visó-Valley project.) Evidently the figures refer to reservoirs with gravity dams only. To give (k 0 ) the cost of 1 m 3 reservoir capacity is a widely preferred way of expressing storage economics. A list of k t data can be found in Table XV and Figure 70, both being based on several books consulted. The relation between the lc 0 unit cost (fillér /m 3) and the index ß is contained in Formula 104. (Table XV and Figure 70 give expenditures in 1936 pengő value. 1 pengő = 100 fillér = 28 USA cents.) The к 0 unit cost may be expressed as a function of capacity (See Formula 105.). General form of the k 0 = | (S) curve is given in Figure 71. Through the k 0 curve, being plotted either theoretically or from definite points, the author gives the y. 0 unit cost for any arbitrary /IS volume on the basis of Formulae (106) and (107) respectively. Based on Formula (107), y. 0, belonging to any arbitrary S value, can be developed from the k 0 curve without any difficulty (See Figure 71.). By repeating this procedure several times, a y. 0 curve of satisfactory precision can be drawn. From the definition of y. u it is evident that the mean value of a y. a curve stretch reaching any arbitrary S value, is exactly the same as k 0 belonging to S in question. Drawing up the y. 0 curve may be of practical importance in case of a multi-purpose development, where unit costs for the parts of a reservoir serving different interests are to be computed. That is the way how to compute unit cost for that part of the basin, too, which is maintained for the sake of flood control. Let us take the example of a designed reservoir providing of water for both hydro-energy generation and irrigation, either of which is of such a great importance that on account of it the reservoir must be realized anyway . In that case partition in theory of the reservoir is possible and cost of the lower, relatively more expensive part can be defrayed by the utilization of primary importance. while that of the upper, relatively cheaper part can be defrayed by the utilization of secondary importance. Our y 0 Figure is highly f it also for deciding whether, in view of the consumers, it be more advantageous to make one single reservoir where the demands of two or more consumers are to be met simultaneously and that diagram enables us to state that through this unification what possible saving may be assured for each of the consumers? In case the geological and topographical conditions permit to use for each of the possible reservoirs the same or approximately the same k 0 curve, the method of solving the problem is explained by the author in Figure 72. Unification of demands of 1. irrigation and 2. hydro-energy generation is possible in two ways as described under a) and b) on the right side of Figure 72. In case b) we have double utilization, i. e. part of water consumed by hydro-energy generation under 2. is available also for irrigation under 1. Examining on the characteristic mass curve the case with an annual reservoir, the graphical method shows that unification here requires a larger <S* 4 capacity that the 8 l + <S* 2 total of separately needed volumes. In case a) unification proves to be economic only if criterion (108) is satisfied. There are several possibilities of dividing costs of an capacity reservoir required by double utilization (irrigation and hydro-energy generation), such as: L. costs saved by unification are shared equally as shown in Formulae (109) and (109'); 2. reduced costs are devided according to a) respective needed capacities (Formulae 110 and 110') or b) investments (Formulae 111 and 111') and finally 3. there may turn up such a k/j unit cost which is just the limit of economy for consumption under 2. the criterion for solving the last variation is given in Relation (112). With hypothesis b ) (partially double utilization) the S 3 necessary capacity is generally smaller than + <S 2, there is no crux in the unification like the one given in Relation (112) and unification here means profitable economics for both of the consumers. With the arrangement shown in the diagram: S 3 4 S l + S 2. Profit resulted by unification can be shared as described above and for that purpose expenditures for the different consumptions are given in Formulae (113)—(117). It is usual to characterize reservoirs for water power utilization also by potential energy in the full basin. (See Formulae 118 and 119.)
