Vízügyi Közlemények, 1948 (30. évfolyam)
2. szám - VII. Szakirodalom
(6) regions in question be identical or not. Straight lines А, В and С characteristic for the investigated regions and the cp values laid down in Formulae (42), (43) and (44) respectively can be taken from Table VII as well. Making the substitution of qu = 1 in equation (36) and considering that in a drainage area of semi-pervious character rp values for any possible extension of the area may vary between 0-8 and 0-6, we get the following result: The examined mountainous region consists mainly of the so called „Carpathian lime stone" and as these regions are of semi-pervious character, for each 1 m 3lsec unit of the mean discharge in the dry year a capacity of 12—16 million m 3 must be secured if a perfectly equalized consumption of the total annual run-off is wanted. In the course of practical design capacity of an annual reservoir can be computed with satisfactory accuracy even if we happen to dispose of no hydrological data. With the map of precipitation (Fig. 3.) given in Chapter III/l. a. of this study and with Formula (7) precipitation of the driest year can be computed with a great accuracy for the investigated drainage area. Explanation for stating average annual precipitation can be found in Formula (46) and Figure 37. The run-off coefficient in Table Il/a gives the possibility of determinating run-off and mean discharge respestively in the driest year, while necessary storage capacity can be computed with relation (36) and Figure 36. In this procedure the intermediate stage, i. e. selection of the run-off coefficient proves to be the most precarious as it is evident from the broad limits given in Table Il/a. The author is of the opinion that through the proposed method very reliable results can be reached if out of the available hydrographical data, discharges of any extremely dry year can be selected even if the examined year itself is not decisive for temporal distribution of discharges. In this case the annual run-off and the mean discharge ( V, qu) respectively are known and with Formula (36) and Figure 36 needed capacity can be computed directly. Comparison of precipitation data, usually available for a longer period, gives a satisfactory control of whether the driest year hydrographically known be really decisive in view of run-off. Through Figure 38 it can be proved that, irrespective of reservoirs serving run-of equalization within a very short period only, for hydrological design of seasonal storage reservoirs it is the storage year decisive for annual reservoirs that must be taken into consideration. Accordingly in theoretical examinations we may use the equation of the characteristical mass curve. If a constant consumption of q — a qk be aimed at, where a < 1, maximum value of s is characterised by relation (4$) with regard to Figure 39 and Formula (47). With an additional substitution (52) to the former ones, relation (49) takes this form: As a general formula, with the substitution of a = 1, it comprises Formula (35) as well. Stored water quantity is given by Formula (54), while Formulae (55)—(57") indicate needed storage capacity. Coefficient ii as a function of« and rp is explained in both Figure 40 and Table VIII. Figures 41 — 44 show hydrographical design of seasonal reservoirs for four different streams, while in Table IX a comparison is made between the hydrographically computed actual values and the figures reckoned with the author's method. Designing engineers might be interested in the following problem: What is the ratio between storage capacity necessary for steadily securing a certain a per-cent of the minimum annual mean discharge and that of an annual reservoir? These relations can be gathered from Figure 45 and Table X with regard to Formulae (59), (60) and (60'). Figure 46 gives the operation of the seasonal reservoir, i. e. the utilization plan for the decisive year, while Figure 47 shows the same for the year of hydrographically average character. S' = 15-7 hm 3 — 11-7 hm 3. b) Seasonal Reservoir. e (53)
