Vízügyi Közlemények, 1996 (78. évfolyam)
1. füzet - Illés L.-Konecsny K.:Az 1995. decemberi felső-tiszai árhullám hidrológiája
50 Illés L. -Konecsny K . It was found that rainfall (Figures 2. and 3.) onto the drainage basin was the most important one among the factors of inducing this flood, although the effects of snowmelt and the frozen ground surface can not be neglected either (Figures 4. and 5.). Runoff coefficients were high, reaching to 0.6-0.7 at some locations (Table Г). The probability of occurrence of this flood was estimated as 2-6%, in terms of the December high flow (Fig. 7.), while it was 8-50% in the light of the time series of annual high flows (Table II.). It was also concluded that in December floods of similar magnitude occur more frequently in the Upper Tisza than in the River Szamos, which latter has a more closed drainage basin (Figures 8. and 9.). The effects of foreign reservoirs (Fig. 10.) on the flood hydrograph were significant in the case of the rivers Kraszna and Túr, while it was hardly detectable in the case of the rivers Szamos and Tisza (Table IV.). The flood warning and forecasting system operated well (Table V.);— 50 water level forecasts proved to be reliable out of the 53 ones made (Figures 11 and 12.).The authors suggest the following steps to be made in order to further develop the flood warning and forecasting system of the Upper Tisza River Valley: — Foreign and Hungarian monitoring networks should be upgraded using identical principles and methods, introducing partial automation of the measurements. The number of monitoring stations should be increased in the higher mountains and should be connected to the international information system; — The direct means of data transmission should be improved in the main regional data collection centres (Nyíregyháza, Ungvár, Kolozsvár); — New forecasting models, which can take the effects of storage into account, should be adopted; — In order to improve flood warning radar-meteorological methods should be developed jointly with the Rumanian partner. To do so, new up-to-date radar equipment should be installed in the Nyíregyháza-Napkor station, to replace the existing MRL-5 device; — Flood hazard prevention and defence information systems should be developed in harmony with the similar developments of the neighbouring countries.
