Summaries The project HISTOS, a hydro-meteo information system for the Oosterschelde Within the organization preparing the building of the storm-surge barrier, a separate project has been set up, known as HISTOS. This organization also works in aid of the construction of the compartment dams. The principal tasks of HISTOS are: the preparation of statements regarding the working conditions of the storm-surge barrier, the study of the water-movement in the Oosterscheldebasin, specially in behalf of the environmental control, and the surveillance of the barrier when finished. The office of the Delta Service, located in Zierikzee, has been designated as the central post for the information system. Provisions have been made within the project for a close collaboration with the K.N.M.I. (Royal Netherlands Meteorological Institute). Results of tests made with caissons on Neeltje Jans While investigating the stability of the barrier usage was made of among other things, large scale models on the construction island of Neeltje Jans. At the same time general research study was done into the phenomenon of the softening of the sea-bed and into the accuracy of the current calculation technics. From the outcome of these tests it became clear that the prognosis regarding the stability of the barrier proves to be much more favourable than earlier anticipated. Other parts of the test are still subject to scientific discussion. It appeared, however, that a construction without a solidified sea-bed and without a sill would collapse even sooner than earlier calculations predicted. The design of the gates for the storm-surge barrier in the Oosterschelde The gates for the barrier have to meet certain hydraulic conditions and technical demands. The water-levels and wave-heights that they will have to retain are summed up in this paper. The height of the gates has been so selected that the probability of being exceeded equals that of the other primary dams in Zeeland, viz.: 2.5 x 10"4 a year. This contribution equally provides a multitude of details concerning the sheeting, the bearing systems, the suspension, the sliding planes and the grooves of the gates. The operating mechanism must be relied upon to function optimally, thus reducing the chance of failure to 2 x 10-3 a year. The set-up the organization and the blending into the landscape of the barrier and the compartment dams. Apart from their retaining function the barrier and compartment dams also have recreational, appreciative, traffic and ecological functions. All these functions are supposed to find also expression in the design and the make-up of the works now, or in any case can be incorporated at a later date. In this connection a number of project groups, purposely set up to this end, have made suggestions regarding the longitudinal and cross sections, the outlay of the roads, the beautification of both the dams and the sluice island in the Oesterdam. A description is given of some of the appraisals 543

Tijdschriftenbank Zeeland

Driemaandelijks bericht Deltawerken | 1979 | | pagina 55