Natural Issues: The Foundational Problem
Though climate change definitely plays a part in this (we’ll get into that later!), the fact is that there are a lot of natural factors that play into Venice’s current flooding issue. The most important factor is that the city is literally sinking.
Most of Venice’s buildings weren’t built on solid rock. Rather, they were built atop sediments that came from the mouth of the Po River. This led to rather unstable foundations. When settlers started to build on these sediments, the buildings and roads started to affect natural river flows, making them more vulnerable to flooding.
Worsening the issue is the fact that the sediments and foundations of the buildings haven’t really settled. Industrial projects like pumping water from aquifers exacerbated. As a result of all the interruption, Venice managed to sink a total of 9 inches over the course of 100 years.