There are a lot of houses built right on the river. If you aren’t on land the country can’t charge you money, so it’s tax free housing. It is also the traditional way of building houses. People would build around the rivers and canals because it’s easy to travel and grow. The land would be flat and wet so that they could easily walk or boat to their destinations. Personally I feel these homes have a simplistic beauty to them even though they are built up like shacks. I imagine the tin roofs must get very hot though in the humid heat of the summer.