King Tides in Venice
While I was holidaying in Venice with my wife Linda recently, the timing coincided with some unusually high tides bought about by a combination of high predicted tides (King Tides) and a low pressure system. The water level on this day was predicted to be around 1.10m on the local datum but reached 1.25m which equated to roughly a 1 in 5 year Annual Return interval water level event (according to local press coverage).
These events are known as “Acqua Alta” which roughly translates to “high water” and warning systems are in place across the city when the predicted water level exceeds 110cm. So on the day we awoke to an eerie series of sirens blasts around 8.00am which sounded like air raid sirens warning of the impending event (see some general information Here). I took a lot of photos in Venice (Burano Island and city of Venice) around the peak of the high tide on 28 October 2018 and some of these are included here (Image 1, Image 2, Image 3, Image 4, Image 5).
You will notice many shop owners and houses employ measures that involve using systems of boards and plates with rubberised seals and locking screws to prevent ingress of seawater around doorways and ground floor windows (you will see examples in the photos). Local crews were going around Burano when I was there desperately helping people to fit the various panels. As you will see these only work up to a certain a level, proving a somewhat desperate short-term adaptive response. In the absence of large scale capital infrastructure, these might become more common place closer to home at areas in NSW already vulnerable to tidal inundation over coming decades.
On this day, the Venice Marathon was also taking place finishing in St Marks Square. As this was submerged the police redirected the finish along the water front where the ferries arrive at San Marco. You can imagine the chaos, which is reflected in the photos as these areas were also under water. It was a rather surreal experience.
The day after however, it is understood water levels through the Venetian islands rose to somewhere between 150 and 160cm (3rd highest water level recorded in 150 years) resulting in the flooding declared an emergency and the city effectively locked down (see press articles in Telegraph and Guardian. There are various pictures in the press of people braving these conditions which are quite frankly dangerous as the sewers do overflow, not to mention the submerged objects everywhere coupled with narrow, cobblestone laneways etc.
Words by Dr Phil Watson. Please respect the author’s thoughts and reference appropriately: (c) ACS, 2018, posted 19 November 2018, for correspondence about this blog post please email email@example.com