Vízügyi Közlemények, 1947 (29. évfolyam)

1-4. szám - VI. Szakirodalom

(16) 5. Types of Reservoirs. Reservoirs may be grouped after the storage purposes as follows: 1. irrigation, 2. water supply, 3. flood control, 4. water power development, 5. traffic and transport (navigation), 6. water supply for industries. In most cases, reservoirs are built to simultaneously meet needs of consumption of various character. Reservoirs may be distinguished according to capacity as well. The customary measuring system in the scientific literature and in engineering practice includes: m

3; hm

3 = 1 million m

3, and 1 kin

3 = 1000 million m

3 = 1 billion m

3. For relative estimation of the size of a reservoir may serve the capacity for one unit of the drainage area (Formula 5 ) and the capacity for one unit of the annual run-off water (Formula 6) which was introduced by LUDIN under the term "degree of reservoir development". In the author's opinion the 7nost appropriate method is to group reservoirs according to relative hydrological output. However, it is not one of the values of the above factor that is to be taken for basis of grouping, but such periods which are characteristic regarding either consumption or run-off. The author is proposing the following grouping partially adapted in the scientific literature: 1. pondage, to equalize daily fluctuation

, 2. weekly storage, 3. seasonal storage, 4. annual reservoir, 5. multi-annual reservoir, 6. reservoir for full utilization. However, while those terms give the corresponding qualitativ definitions, the author is giving to each of them quantitative definitions based on hydrological conception as described in Chapter TV of the present study. 6. Fundamental Principles of Hydrological Dimensioning. Hydrological investigations bring forth the utilization plan of the reservoir. This plan is determined by the character of consumption: s (t), by the absolute value of average consumption: fk m

3/sec, and by the useful capacity of the reservoir: 8 m

3. Out of these three features two must be known in order to determine the third one and thereby to draw up a utilization plan. Consequently three kinds of hydrological problems may turn up, all of them dependent on the unknown factor: Known: Unknown: 1. f

k and e (t) S 2. s (t) and S f

k 3. S and fk s (t) Following are the factors that have a bearing on dimensioning: I. Natural conditions for storage: a

) natural stream-flow conditions (hydrology), b

) topographical and geological conditions of the basin and those of the dam site. II. Conditions of consumption, i. e. quantity and fluctuation of needed water. III. FACTORS OF HYDROLOGICAL INVESTIGATION. 1. Natural Conditions of Storage. a) Stream-Flow Conditions. To investigate hydrological conditions one must know the actual drainage area which, in many cases, coincides neither with the topographical nor with the geological watershed (Figure 2), and owing to several circumstances (e.g. frozen soil surface) is somewhere between the two. Characteristical discharges for storage are as follows: a) minimum: q

0, b) maximum possible discharge: Q

ma

x , c) the mean discharge in the most arid period of 12 months: q

k, and d) the multi-annual mean discharge: Qk- The former (qk) may be called minimum-, the latter (Qk) average annual