This cannot be compared with Venice, which is a city with all its basic amenities functioning except they commute in waterways. The people of Venice don't have to walk in waist deep water. Each year many Bangladeshis have to bear this pain and our usual response is "hey they are used to this".
So why do people cling to their dwellings in these locations? Tahmima Anam tries to answer the question in her article in guardian.co.uk about the char-dwellers of Bangladesh:
"Who owns the land," I ask, "is it the government?" He smiles in such a way that I feel foolish for even asking. Of course not; a place that will only exist for an unknowable amount of time is not going to come under the umbrella of the state.Here is a great album- photographs by Hasan Bipul.
Chars don't become habitable until they are a few years old. You can tell their age, Bahar tells me, by the wild plants that grow on them. When chars are taken by the river, often their inhabitants have to move in with their relations, or find some other piece of land on which to build a house. In any case, they will only have enough on which to live: they have nothing to till, so the men hire themselves out as weavers or day-labourers. This is why, according to development-speak, char-dwellers are the "hard-core poor". It is because they own nothing, and even the ground beneath their feet is a fleeting luxury.