Some of which have been moved brick by brick to higher ground. There's one city that's right at one of the junctures and built right on top of the water. Most of the city was projected to be underwater, so they decided to build a giant wall around the city to keep the waters out. It happens that in order to get the building material necessary, they had to demolish about a third of the city.
(I can't remember the city's name -- but the true loss is that there were a bunch of rocks by the shore which had things carved into around the 8th century. Records of floods and where the water level was so long ago and now it'll be under 20 feet of water at the low tide.)
But then it occurred to me (80% tongue-in-cheek) -- isn't the Chinese solution to everything to build a wall?
We want to allow larger ships on the Yangtze! Hey! Let's build a wall!
Our city's going to be underwater! Hey! Let's build a wall!
There's a horde of Mongols that are bugging us! Hey! Let's build a wall!
My tea's cold! Hey! Let's build a wall!