Hidrológiai Közlöny, 2017 (97. évfolyam)
2017 / 3. szám - MANAGING ENVIRONMENTAL RISKS - FLOOD PROTECTION EXPERIENCES AND COOPERATION IN THE DANUBE RIVER BASIN - Gombás Károly - Balatonyi László: Extremities in winter season - outlook for mitigation measures
Károly Gombás and László Balatonyi: Extremities in winter season - outlook for mitigation measures 83 ice protection regulations are always based on the intergovernmental bilateral water management cooperation agreements, the cross border treaties. These regulations in most cases have - as part of the water damage protection regulation - different level of details and different technical content adjusted to the local conditions concerning the management of the ice situations and the necessary measures. The jointly established ice protection regulations always incorporate section description, detailed site plans, longitudinal profile and cross section, hydrological specification, previous experiences and data of hazardous sections, organizations, intervention protocol etc. For river sections with high importance, more detailed ice protection plans were made over the general regulation (e.g. Du- nakiliti SK-HU, Dunaföldvár-Vukovár HU-HR-SRB). The joint ice protection plans contain the adequately detailed elements described above and over the general regulation also include the intervention plans, the detailed description of the joint measures. The ice protection tasks done by icebreakers is a special case as Hungary - compared to the neighbouring countries - has a significant icebreaker fleet of 19 ships. The operation of this fleet beyond the borders is necessary also for the protection of Hungarian territories. Separate regulation administers the ice breaking tasks regarding for instance the Serbian and Croatian relations. These regulations determine the ice protection levels: I. degree - icebreakers in standby at their harbour location, II. degree - deployment of the icebreakers at their assigned position ready to depart, III. degree - execution of icebreaking tasks, extraordinary alert. The regulations also administer the bearing of the costs and the extent of the area of icebreaker operation. CHARACTERISTICS OF THE ICEBREAKER SHIPS This chapter is based on the presentation of Mr. Pál Kőtél, navigation expert of the North-Transdanubian Water Directorate (EDUV1Z1G, owner of „Széchenyi”), which was performed during the XXXV. Annual Conference of the Hungarian Hydrological Society in July, 2017. The icebreaker ships are vessels with special features for effective manipulation of ice. There are many varieties based the body size, the water displacement (weight), equipment and development generation. The crew has to meet strict criteria and the working on these ships is legally considered as extremely dangerous in Hungary. The vessels can only operate in grouped formation at least of 2 units for security reasons. The tasks of these vessels are usually to delay the setting of ice cover and reduce the possibility of the stopped, congested ice become an ice wall. If it has happened they are breaking up the congested ice and creating or maintaining a corridor through the fully-iced river surface in order facilitate ice and water flowing, additionally provide space for transport. Specialties of the vessels - not all of them possess with the listed elements bellow or the features are diverse:- Scrolling equipment: puts the boat in a tug-twisting motion so it can break ice not only by its weight but by its movement energy also. The schematic upbuild is shown in Picture 4.- Reinforced bow formation: 20 mm thick high- strength steel sheet covering (6 mm on normal vessels)- Special hull reinforcement system at the bow with so-called ice-frames- Spoon-based bow formation for better discharge of broken ice- Special stern design: effective ice breaking in reverse movement- Propellers are made from steel for smashing ice (Kötél 2017). Picture 4. Conceptual illustration of the scrolling equipment (Source: Magyar Hajózásért Egyesület, http://www.hajoregiszter.hu/ Unfortunately due to the shape and the build-up of the ships they are dedicated to their function and less deployable for any other purpose. That is the reason these ships are standing by at their harbour most of their lifetime. A noble drive through in front of the Hungarian Parliament was captured on Picture 5. Picture 5. The “Széchenyi" Hungarian icebreaker fleet flagship in front of the Hungarian Parliament in 2017 (Photo: © OVF) EXAMPLE OF AN INTERNATIONAL COOPERATION IN WINTER, 2017 (HUNGARY- CROATIA-SERBIA) Due to the meteorological circumstances January/2017 was the 10th coldest January since 1901 and the coldest since 1985. The minimum temperatures were below the freezing
