Rubber dams may save Venice

Press, Volume CXIV, Issue 33675, 26 October 1974, Page 21

Rubber dams may save Venice

Z F A.-Reuter —Copyrights VENICE. An Italian business onsortium has suggested that three huge, iater-filled rubber jibes are the way tc ave Venice from high seas which every year lood houses, streets, and xjautiful historic buildngs. The three tube-dams, mads >f polyester covered ir waterproof rubber, would bi ible to block the tide Zhioggia, and Malamoccs thannels through whic) water enters the Venio agoon. At present this wate 'lows in unchecked, am when there are heavy sea :he beautiful St Mark’ square, the most famou andmark in the city, i sften knee-deep in watei The homes of the lagoo city’s inhabitants are affect •d by flood-waters about 2 jr 30 days a year. The three dams, propose by a consortium of Pirell :he Italian rubber giant, an Furlanis. an Italian construe tion firm, would be con pletely emptied during noi inal seas and would lie dot tnant on the bottom on th sea. But in high seas the could be quickly pumpe full of water to provide a sffective barrier. The consortium believe that these flexible dan would not only be the be; solution for the unique prol lems of Venice, but woul also be useful in other pan pf the world. The consortium's engineers say a conventional con-

|crete-and-steel dam would, ideface the unique beauty of I 'Venice, would interfere with 1 shipping, would be very ex-i ! pensive and — perhaps most! iimportant of all — would' upset the lagoon’s delicate egologica! balance. Although one of the city’s I greatest problems is flooding. which is becoming! i worse every year, paradoxically, health authorities ■ say, the high seas perform aj valuable function. They! .ensure that the water in I Venice’s hundreds of canals! ;is changed frequently and' 4 that accumulations of pollu-1 tion and sewage are taken 'lout to sea. ! If concrete dams with ’gates were built, in the words of the Pirelli con’i suitant, Professor Arturo 1 Colamussi, “Venice would be closed m on itself, and a > serious health problem could > arise.” ’ Furthermore, says the i ) 1 i e f i a s s it Id s

,consortium, a concrete dam. ■would take some time to build, and would cost about: !SUSIBm. , They say that, in contrast,' Their dam would take about' Two years to install and! j would cost between! SUS23.Bm to SUS3Sm. ■ The Pirelli-Furlanis dams j I would not be visible when I not tn use and so would not! i spoil the view for which! jmillions of tourists flock to' ! Venice. ! The dams would be! [anchored to the sea bottom by chains attached to seven- . feet wide concrete pylons [driven 40 to 50 feet into the ! sea-bed. '! Pirelli says that tests so ■(far show that there would [be negligible movement of 'ithe dams along the .sea-bed 'seven when deflated, and that L ; they would not rise up from I'the bottom, in a way which [would affect shipping, when dhit by strong currents.

The tests also show J Pirelli says, that the flexible! dams would mould them-’ (selves to the sea bottom,! ■even if this is uneven, and! there would be little seepage lof water underneath. , The flexibility of the dams. ! would also mean they could I absorb the force of heavy! seas and currents instead of! ! rigidly meeting them like a: I concrete dam. If a con-; I ventional dam is subjected; Ito greater forces than it is; ibuilt for it will buckle and! ! collapse, the consortium’s! engineers say. Pirelli’s engineer, Mr| Bruno Borco, says he) believes that the dam .was; !so flexible and able to absorb force that it would not; I;be punctured by a rifle bul-! let. l! There already exists a systjtem of meteorological stall tions around the north-east-, ijern Adriatic Sea which give i(Venice a six-hour warning lot high watens.

| This early-warning system ! could be linked to the dams: by a computer which would; ! automatically activate tur- | I bine pumps at each end so; ithat the tubes were filled: | with sufficient water to, ■ raise the dams to the right! ! height to resist the sea. I In all but the most severe leases, a 650 ft wide gap i would be left in the barriers •| so that shipping could continue to enter — thus alleiviating the dislocation of! ! shipping that a conventional I dam might involve. But in very high seas the! central gap could also be | closed.