what is the low cost solution for flood control inside a city?

Question

there is two river inside the city of Sao Paulo,brazil. I want to know if there is a very low cost (afordable) solution which is more natural than mechanical to control the flooding inside the city.

Answer 1

Unfortunately, there will be no low cost solution once the city has grown around the rivers. The low cost approach would have been leaving the flood plains natural (typically agricultural) or areas the can withstand the periodic flooding. This is a problem with flooding in many American cities also.

Some of the more natural things (probably not too popular) that can be done are:

1. Restrict all development in the flood plains (therefore removing the need for the owners of structures clamoring for levees for protection once they are flooded).

2. Remove restrictions in the flood plain (i.e. things such as trash and large brush piles can turn into blockages at bridges and culverts creating larger problems in the flood).

3. Get the people involved in the project. Once on board public support is the cheapest thing you can get. Politicians are expensive.

Answer 2

Flood control dams upstream, levees, or flood diversion channels are the only known means of controlling flooding along a river.