HIGH TIDES

The term 'acqua alta' refers to the phenomenon in which a number of areas of the city are flooded. This minimum 'acqua alta' is a high tide of +100 cm which corresponds with a depth of a few centimetres of water in limited areas of the historic centre.

Wooden walkways that are positioned in various zones of the city to allow the normal flow of pedestrain traffic when the high tide exceeds 120 cm (flooding 35% of the city). However, it is only when the height of the water exceeds 130 cm (flooding 70% of the city) that the effects begin to cause serious problems. When the water level reaches 140 cm (90% of the city flooded) this is considered an emergency, but statistically, the cases of high tides of this level are quite rare (approximately every 2 to 3 years)

The 'peak' of a high tide only lasts for a few hours.

PRINCIPAL CAUSES OF ACQUA ALTA

1) Astronomical - the attraction of the sun and the moon cause the rising and falling of the sea. The cycle of rising and falling is every 6 hours, so in every day there are two high tides and two low tides.

2) Meteorological - the wind factor (scirocco), added to the gravitational effect of the moon, can cause the level of the water to rise by up to 1 metre.

INFORMATION IN REAL TIME

Centro Previsioni e Segnalazioni Maree (tide forecasting centre)
Palazzo Cavalli, S. Marco 4090 - 30124 Venezia
tel. +39-041-2748787 fax +39-041-5210378

Pre-recorded information +39-041-2411996

www.comune.venezia.it

maree@comune.venezia.it

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