Vízügyi Közlemények, 1965 (47. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

<118) COMPLEX RESOURCES DEVELOPMENT IN THE NYÍRSÉG REGION By Gy. Szeifert, Engr. (For the Hungarian text see pp. 435) The area lying south of the Tisza River in the north—eastern part of Hungaryis referred to as the Nyírség Region. Surface and underground runoff from the series, of sand hills dominating the region is collected by nine major watercourses (denoted! I to IX) and discharged through the Lónyai principal canal between flood levees, into the Tisza River (Figs. 1 to 3). The entire catchment area covers 1646 sq. km, the length of the canal system related to the entire catchment is 6.6 m/hectare, providing a specific discharging capacity of 13.3 1/sec.sq.km, which in the Lónyai canal increases to 20 1/sec.sq.km. The objective of the paper is to outline the possibilities for resources management in the Nyírség Region. The dominant feature of resources development consists of storage of runoff waters, this in turn being controlled on the basis of hydrological data. Special attention is therefore devoted to problems relating to precipitation and runoff. Detailed information is presented on annual sums and distribution within the year of precipitation, the significance of which is underlined in view of its import on the planning objective. Typical for meteorological conditions in the region is the circumstance that wet winter seasons are followed by arid summer seasons with little rainfall, while springs and summers with abundant precipitation occur usually after dry winter seasons. Under such conditions storage is the logical solution. Part I of the paper is thus a preliminary report on hydrology, in Chapter 2 of which numerical values are presented in a tabulated form (Tables 1 to V) on various elements of the waterbalance for the region, such as aj precipitation (Figs. 4, b) runoff, c) evaporation and d) storage conditions. Probability theory is applied in Chapter 3 to develop various relationships a

) between meteorological conditions, the size of the catchment area and runoff volumes (Figs. 6 and 7, Table VI), b) between meteorological conditions and volumes stored in existing reservoirs and which can be accomodated in contemplated ones (Fig. 8), c) between meteorological conditions and flows in the Lónyai principal canal, as well as d) between meteorological conditions and water volumes available for resources development (Figs. 8 to 12, Tables VII to XIII). The objective of watershed control in the Nyírség Region is to increase the present drainage capacity of 12.3 1/sec. sq. km to 20 1/sec. sq. km. This can be achieved either by a major reconstruction of the system, or by the construction and operation of reservoirs. Each reservoir (see Fig. 1 for the location and Table VII for the main data on existing and planned reservoirs) is capable of receiving waters of a certain drainage area and to thus relieve canals and main canals to a corresponding extent. Runoff from altogether 536 sq.km can be intercepted and thus the existing canal system is capable — by enlarging certain canal sections only — to deal with the runoff reduced by the volume retained in the reservoirs. Construction of reservoirs can be solved by simple and inexpensive means. For this end multi-purpose sluices (Fig. 17) are simply built into canals where these cut across sand hills. Reservoir sites (about 20 over the entire area) as well as dimensions and equipment of multi-purpose sluices were selected to satisfy sometimes conflicting requirements of drainage, flood control for the Lónyai principal canal, and utilization of water (irrigation, fisheries and secondary uses). Relying on the hydrological preliminary study possibilities of resources development are considered in Part II of the paper. Chapter 1 is devoted to the potential means of development, such as a J drainage (Figs. 13 to 15 and Tables XIV to XVI), b) storage (Figs. 16 and 17), c) flood control (Fig. 18, Tables XVII to XIX), d) use of water (Table XX). In Chapter 2 a) costs, b

) the period of realization and c) results obtainable are discussed. As a conclusion of these studies it is demonstrated that the conveyance capacity of the canal system cannot be increased economically without storage.