Let it flow!
Dams cause way more problems in the long run than they end up fixing. The only reason we need flood control is because we're building to close to the river and not respecting the high-water flows that are needed at certain points of the year. Putting in a dam may 'fix' flooding problems, but you now have another piece of infrastructure that needs to be maintained, and people think they can safely build tight to the water because it's 'controlled'. The dam allows silt to accumulate, destroying fish habitat and eventually causing safety issues if not maintained. On large rivers damming the river prevents the silt from travelling to the outlet of the river, where it is needed to form barrier islands (ask New Orleans how that works after Katrina).
The Dutch have started an interesting project called 'Room for the River'. They don't view the river as something to be conquered or subdued, but rather have begun designating and creating flood plains to deal with the highest expected flows of the river. This does not prevent floods, but gives them somewhere to go. Plus the flood plains become green space the rest of the year for all to enjoy.
In the US there have been some interesting dam removal projects (the Elwha river is a notable one) and the return to natural landscape and the return of native wildlife has been much faster than was expected.