Vízügyi Közlemények, 1965 (47. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

'(42) HYDROLOGICAL SERVICE IN THE U. S. A. By Dr- К. Szesztag, Engineer (For the Hungarian text see pp. 147) Climatic conditions over the territory of the U. S. A. are extremely variable (Fig. 1). The fundamental problem in water resources management is consequently due to the uneven distribution of surface water resources (Fig. 2). Administrative problems arise from the fact that each of the 18 large river systems is shared by several states and five are international catchment areas (Fig. 3 ). Hydrological Service is called upon to render assistance in solving practical problems of water resources management caused by the rapid increase of water demands — and especially those of industry — the rate of which is in excess of resources development (Fig. 4). Flow measurements on rivers in the U. S. were started at the beginning of the last century (Fig. 5). Regular hydrological activity was first exercised in 1802 by the U. S. Army Corps of Engineers, followed in 1889 by the U. S. Geological Survey and in 1891 by the U. S. Weather Bureau. Federal hydrological service received valuable contribution from the U. S. Forest Service and the U. S. Soil Conservation Service, Department of Agriculture, who established a network of hydrological experimental areas, as well as from the U. S. Public Health Service, Division of Water Supply and Pollution Control, who performed extensive quality studies. Besides federal agencies important hydrological work is carried out by state hydraulic and geologic services, as well as by major hydroelectric power, irrigation and flood control companies and universities. Besides the contemplated large-scale extension and automation of the observation network, the characteristic feature reflecting the development of the central hydrological service is the growing role and significance of research work (Table, Fig. 6 ). The area pattern and envisaged development up to 1972 of the observation network complies with changes in natural and economic conditions (Figs. 7, 8 and 16). The number of stations equipped with conventional rain gages is relatively small (Fig. 9), but data evaluation and generalization is greatly facilitated by grups of stations established temporarily for study purposes and the radar network (Figs. 15, 16 and 17). Increasing attention is devoted by the Geological Survey to the comparative study of flood conditions (Fig. 11) and to the exploration of subsurface water resources (Fig. 10). Development of the surface is reflected also by the growing numb er of annual publications (hig. 12). From among hydrological activities performed within the framework of the meteorological service, flood forecasts prepared by river forecasting centers and other central, or regional agencies are most important (Fig. 14 ). On the basis of experience gained during a six-week study tour in the states of California, Arizona, Alabama, Illinois and Washington in Autumn, 1963, a report was published in a recent number of this paper by the Author, in which results and plans relating to the automation of the work in the hydrological station network were described [9]. OPERATION OF THE TISZALÖK IRRIGATION SYSTEM By L. Dávid, Engineer (For the Hungarian text see pp. 173) The largest irrigation system at present in Hungary is the one at Tiszalök, which operates since 1954. Relying on experience gained during this period, operation of the system in 1964, as a stage in the development thereof, is subject to a detailed analysis. The irrigation system covers 3000 sq.km in the eastern part of Hungary. The boundaries and layout of the system are shown in Fig. 1. Water resources originating in the area are insignificant, consequently the only supply to the system is diverted from the Tisza River at two points, namely at the gravitational diversion from the backwater reach created by the Tiszalök barrage and through the pumping