Vízügyi Közlemények, 1998 (80. évfolyam)
4. füzet - Petrőcz Bálint: Győr árvízvédelmének fejlesztése
598 Petröcz Bálint Országos Vizügyi Hivatal: Árvízvédelem Folyó és Tószabályozás, Víziutak Magyarországon és Árvízvédelem, Budapest 1987. Ihrig Dénes: A magyar vízszabályozás története. Bp. 1979. Mosoni-Duna és Rábca menti védvonalak fejlesztése, Kézirat, Bognár Pál—Szűcs Ferenc-Németh Sándor ÉDUVÍZIG: Árvízvédelmi Fejlesztési Terv és aktualizálásai, Petrőcz Bálint—Szabó Miklós-Szücs FerencNémeth Sándor » * * Development of flood defence for the city of Győr by Bálint PETRŐCZ, C.E. Győr, the „city of waters,,, is located on the northern rim of the region called the Kisalföld (the Small Plains). Györ is located at the confluence of three tributary rivers, the Mosoni Danube, the Rába and the Rábca with the River Danube. Within the city's administrative limits there is one more river, the Marcal, and several smaller streams and canals (Figure /.), like the industrial canal, the streams Kis- and Nagy-Pádzsa and the Holt-Marcal (the Oxbow Marcal). The length of the rivers within the city is 34.9 km of which 18.5, 9.1, 3.2, 1.7, and 2.4 km long sections belong to the rivers Mosoni-Danube, Rába, Rábca, Marcal and industrial canal, respectively. The length of the flood levees corresponding to the above named rivers is summarized in Table I. There was, in January, 1969, a substantial change in the flood defence organization of Győr. In harmony with the provisions of Government Decree No. 39/1968 the District Water Authority has taken over, from the City of Győr, the responsibility of the handling of the flood defence lines of river reaches which fall within the city limits. The height of the defence lines were 0.5—0.6 m lower than what was requested by the regulations of those days. The technical conditions of flood-walls were not satisfactory. In order to improve the safety of the city against floods the Észak-Dunántúli Vízügyi Igazgatóság (the North-Transdanubian District Water Authority) deemed it necessary to rise the height of the levees and walls to the required level and to strengthen the structures. For the development of the flood-defence facilities of Győr the ice-free flood of 1000 year average return period (the 1000 year ice-free flood) was considered as the design flood. Nevertheless, there was a reliable hydrological record available for the last 70 years only and therefore instead of the water stage of the 1000 year ice free flood (H ma x, 0.1%=1 15.06 meters above Baltic Sea level, m В. S.) as calculated with the help of various distribution functions was not considered a reliable value. Instead of this former the reliable estimate of the level of the 100 year ice free flood (H ma x, j Oo / o= 114.42 m В. S.) was considered as the basis of flood defence design activities. Thus, the design height of the flood defence lines of the city was specified as the water stage of the 100 year ice-free flood plus a safety clearing of 1.5 m. Within the limits of the city the height of defence lines was thus built to 115.92 m В. S. with 4.00 m crest-width. The crest is of the „beetle's-back„ type and the side slope is 1:3 with humus upper layer of 0.2-0.25 m thickness (Fig. 2). Flood defence walls (Figure 3.) were erected at places where there was no sufficient place for the earthen flood levee. Quantities of the construction works are summarized in Table II. In the 1st period of construction the right-bank levee of Mosoni-Danube and the 7810 m long dike along the industrial canal were constructed (Figure 1.). An ,,L„ shaped flood-defence wall was built for the section between river kilometres (r.km) 6.827-6.810 with 2.0 m foot-width and 2.98 m height. A reinforced concrete shuttering-panel of a gravelly surface, which stays in place, was made on the outer surface of the wall so as to provide an attractive appearance. When the working pit of the flood-wall of Dunakapu square was made, the underwater part of the long forgotten „water-bastion,, of the old fortress of Győr has been discovered. Reconstruction of the bastion was made with
