I am frequently asked all sorts of questions about canals: how deep are they? do they smell? are they ever cleaned out? This picture provides alot of those answers ( except for the smelling part) , and gives an interesting view into how canals are maintained here in Venice.
From time to time you'll walk past a canal such as this one. It has been blocked off and dredged. The process takes weeks, possibly longer, I personally have not yet witnessed this event from start to finish so I can't tell for certain. While the canal is dredged, repairs are made-- it's all a very necessary process. A little sad to see a canal in this shape, because normally they are beautiful, each and every one of them. But- the end result is worth the temporary disruption.