Venice

If any area will flood, it will be Piazza San Marco. You can look at webcams to see current conditions. https://www.skylinewebcams.com/en/webcam/italia/veneto/venezia/piazza-san-marco.html

Hello ruthmseidel, and welcome to the forum,

The city monitors and knows when "high water" is coming and how high it will be. Platforms will be set up to walk over the water by city workers while they are needed. All the places in Venice know their "height" number and whether the water will reach there. Piazza San Marco is some of the lowest parts of the city and is most likely to flood. You can avoid it by heading to the higher part of the city instead.

Just to be clear when the water comes up it creeps in and the drains essentially "run backwards" and fill the street before draining back out. It does not rush in like a wave or anything. The Venetians just live with it like people from other areas deal with snow, rain or dust or something.

March is end of high water season so hopefully you'll get lucky, but it not you just need to be smart about it,
=Tod

There is an app, WVF (Water on the Venice Floor) that gives you a map showing inundation.
Also hi tide venice is a handy app.