Vízügyi Közlemények, 2003 (85. évfolyam)
2. füzet - Hankó Z.-Bauer M.: A bősi vízlépcső üzemvízcsatornájának hidrobiológiai (ökölőgiai) változásairól
222 Hankó Z.-Bauer M. Mucha, /.: Gabéíkovo-Nagymaros Hydropower Project, Gabcikovo Part of the Hydroelectric Power Project, Environmental Impact Review (Evaluation Based on six Year Monitoring). Published for the Faculty of Natural Sciences, Comenius University, Bratislava and the Plenipotentiary of the Slovak Republic for Construction and Operation of Gabéíkovo-Nagymaros Hydropower Project by Ground Water Consulting Ltd., Bratislava, 1999. Sebestyén О.: Bevezetés a limnológiába. A belvizek életéről. Akadémiai Kiadó, Budapest, 1963. Vágás, /..- The Gabéíkovo-Nagymaros River Dam Project. European Water Pollution Control, Vol. 1., No. 5., Lelystad, 1991. * * * On the hydrobiological (ecological) changes of the power canal of the Bös/Gabcikovo Power Station by Dr. Zoltán HANKO С. E. and Dr. Mária BA UER geologist, sanitari engineer Professionals have been dealing with the flood-control, river training and channel-management issues of the Danube reach between Bratislava/Pozsony and Budapest since the middle of the 19 t h Century. The problems of this river reach cannot be solved solely by river training methods: the only solution is provided by river canalisation, by the building of river dams. This condition resulted, in 1963, in a Common Investment Programme of the Slovak (that time Czechoslovak) and Hungarian partners, followed later by a bilateral agreement in 1977 on the construction and operation of the Gabcikovo/Bös-Nagymaros hydropower scheme (Figure 1.). The construction was suspended by the Hungarian partner in 1989, not allowing the putting of the already completed river barrage of Dunakiliti into operation, and refraining, in a unilateral way from the contract in the spring of 1992. This was not a very fortunate decision and resulted in the launching of two further processes. The first was the applying of the Hungarian and Slovak partners, with mutual will, to the International Court of Hag, seeking a judgement in the matter of their debate. The second one was that the Slovak partner commenced the construction of the so called "Variant C", the construction of the Dunacsúny River Dam (at about 10 km distance towards upstream from the existing Dunakilit dam, on Slovak territory (so as to substitute the function of the Dunakiliti Dam). When the Court of Hag released its judgement in 1997, the Cunovo/Dunacsúny river Dam and the hydropower station of Bős have been in operation for 3 years. The judgement of the Court requested the parties (Hungary and Slovakia) to launch a dialog and try to find, vial bilateral discussions, the "modus vivendi"" (the method of co-operation), which complies with the principle of "pacta sunt servanda" (namely, that contracted obligations must be complied with). This "modus vivendi ' has not been found ever since and there is no result either in complying with the principle "pacta sunt servanda". Thus the upper sub-system, the Dunacsúny/Cunovo-Gabcikovó/Bős Power Canal system, of the Gabcikovó/Bős—Nagymaros Hydropower Scheme has been in operation since 1993 in a unilateral manner (producing electrical current and profit to Slovakia, also in an unilateral way). The original hydrobiological/ecological conditions (before the construction of the Gabcikovó/Bős-Nagymaros Hydropower Scheme) of the Bratislava/Pozsony—Budapest Danube reach can be called a "potamobiological" one (riverine-type). This conditions prevailed in spite of the intensive and heavy anthropogenic impact on the natural development of the river in the 19 lh and 20 t h centuries (in the form of flood-control, river training and channel-bed regulations). The potamological character and the related hydrobiological/ecological (riverine-type) state of this river reach has not been changed upon the operation of the
