Vízügyi Közlemények, 1973 (55. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

(72) the model were linear functions. The assumption of linearity was a necessary compromise (due to limited computer capacity) and became a source of innumerable errors, of which the divisibility of the projects, the determination of unit costs and the technically impermissible realization of increasing benefit caused the greatest difficulties. The development of the model was solved according to the order of activity of an organization network by a research group including engineers, mathematicians, economists and other professionals. The linear model developed contained 463 conditions and 847 variables. The majority of conditions consisted of natural water balances. The variables represented the degree of realization of the potential alternatives of system elements serving different purposes (diversion, treatment, conveyance, storage, etc.) in space, time and at diverse technical levels. The price system valid in 1970 was considered in the model. The programming of investments was subject to budgetary controls. The elements of the potential water supply systems were evaluated according to their investment and operating costs. The numerical solution of [the model revealed trends in the following sense: a) Are local waterworks preferable to the construction of long distance pipelines '? b

) Which watercourses should be selected in the perspective future as sources of supply and which should be excluded? c

) The construction of local, or regional reservoirs appears to be economically superior in the distant future, etc. The solution of the numerical model included all the errors anticipated on the grounds of the theoretical considerations. Capacities were realized almost without exception below the value limit and their realization extended to several time periods. System models of this type may fit well into the planning models of the national economy, into the system of sectorial, complex and regional models, so that they may become the foundations for the formulation of long range planning behaviour. BRIEF PUBLICATIONS AND BEPORTS 1. Lötz, Gy., Civ. Engr.: The water level of Lake Balaton; in the first half of the 19th century (For the Hungarian text see pp. 337) Concerning the water level of Lake Balaton in the first half of the 19th century no more than uncertain data were available, some of which were estimated on the basis of hypotheses. In the archives of the competent district water authority (Szombathely), among the records of a former drainage association data on a direct lake survey were encountered indicating the water level between 1820 and 1840. Moreover a map of the valley of the Zala Biver from 1836 was also detected. On the map to scale 1:21600 indicating level data the profile of the Zala Biver discharging into Lake Balaton is also shown. The vertical scale of the profile is 1:120. Conversion to the present datum level was possible on the basis of sill elevations of former water mills, which could be traced in the archives. From these data it could be concluded that in the first two decades of the 19th century the waterlevel in Lake Balaton ranged from 108 to 109 A. O. D. and dropped to between 106.5 and 107.5 A. O. D. by 1822. This was maintained up to the opening of the Sió Canal. Dr. Szakatsits, Gy., Civ. Engr.: 2. Chute spillways with collecting flun.c at reser\oir dams (For the Hungarian text see pp. 342) At spillways of reservoir dams the collecting Hume is an organic part of the lateral weir, which conveys the water to the chute. A basic condition in hydraulic dimensioning is that.