the tubes. I believe flooding is partly caused by the roads because it blocks water from getting absorbed by the soil underneath. Water is meant to be shared by bodies of water and by bodies of land for good balance. Canals channels water in the end to the sea which for me is not so right. For me, canals or water ways should both channel and absorb water all at the same time. If these tubes won't affect road safety for cars and other vehicles; and weaken the structure of roads, canals, and all the others above then it would be fine but I believe it won't because the length of the tube would prevent the soil foundations of the roads and all the above from weakening. Besides there are buildings who stood even if their surroundings are not cemented at all. I have a