There has been quite a bit about this on Discovery Channel and National Geographic Channel in the last couple of years. It is a very serious issue, but how to resolve it is an entirely different thing... after all, who wants to take down the levies on the Mississippi to allow the silt to free-flow into the Gulf once again? or the Levies around New Orleans that hold back the Mississippi and the Lake?
In the 'old' days they delt with the floods which washed the silt through and kept everyone at the same land-level. Then we decided to control mother nature... goes back to the "for every action" axiom.