Vízügyi Közlemények, 1996 (78. évfolyam)

1. füzet - Pálinkás Lajos: Árvízvédekezés a Körösökön

Az ái-vízvédekezés a Körösökön 123 coverage with sand-bag weights was applied onto the water-front slope of the dike. Furthe r gravel and sand-bag stripes were used to provide counter weight on the land-side of the levee. On the same day there was a left-bank side dike rupture in Rumanian territory, not far from the Hunga rian border, in the 4,500 m section of the stream Csohos. The opening of the dike of the Mérges emergency flood-storage reservoir was made by earth moving machinery (Fig. 8.). First the dike was pushed towards the land-side by front-dosers and then two dredgers, working against each-other along a width of 10-15 m were opening the dike. The final width of the opening was 70 m. The final opening was made at 1:30 p.m on the 30th of December and the equalization of the water levels of the river and the reservoir was achieved at 6:00 a.m on the 6th of January. The area inundated was 1823 ha and the water outflow volume amounted t о 38.8 million m

3. Closure of the opening commenced on the 3rd of January 1996 from the water side by the joint forces of ÁBKSZ (Flood and Excess Water Defence Organization) and the Water A uthority of the Körös River Valley, using Larssen Neu III. type sheet-piles ( Fig. 9.). Larssen piles of a total area of 1285 m

2 were driven into the opening. Gates of 10 m width were left open and they operated appropriately until the 20th of January, when backward moving erosion damaged the struc ture. Erosion cut back into the dike until the crest line of the levee. The reservoir operated wit hout interruption until the 22nd of January {Fig. 10.), when a flood wave arrived on the River Fekete Körös and the gates had to be closed rapidly with a coffer dam made of CS2-M sheet piles. This work was fin ished before the peeking of the flood on the 24th of February and thus the reservoir has not bee n inundated again. Two temporary pumping stations installed on the left-bank levee of the Sebes-Körös , one at Vámoszug (2 m

3/s) and one at Mihályzug (1 m

3/s), were used for the dewatering of the reservoir, along with Canal II1.1 of the reservoir area that conveyed water gravitationally to the p umping station Büngösd II. The total water volume stored in the reservoir was 38.3 million m 3 of which 34.9 million m

3 was drained through the opening, 2.4 million m

3 by the temporary pumping stations and 1.5 million m

3 by the pumping station Büngösd II. Major data of the defence operations are included in Tables 1. and II. Detailed evaluation of the flood defence of the Körös river system have been carried out on the 24th of April, 1996 with the participation of the leaders of the ministry KH VM and the nati onal water authority OVF. Some of the major conclusions are as follows: — Due to the flood regulation works of the last 10-15 years of the Körös River Valley flood water levels have been continuously increasing at the country border stations. This n ecessitates the development of the technical means of operating the system of emergency flood storage basins, along with the improvement of forecasts and the means of continuous ope ration control. The installation of an intermediate water level gauge would be nece ssary between the stations Hondo and Kisjenő. — The role of flood-fighting teams is invaluable. Improvement of these teams calls for ur gent action, with special regard to their regional role. — There is an increasing demand, by the leaders of the defence operations, for improved к nowledge on the condition and processes of the flood levee and the subsoil. — Professional of the water authority should get acquainted with PR activities in order to be able to inform the public in a correct ways.