Need Help With Water Terrain

How do I get the water to dip into the land without ramps if the map is already created? Thanks in advance.

None that I know of, unless you started by deep or shallow water and raised the stuff up, which I seriously doubt...

You could make a new map and Copy the terrain, even the tiles can be copied.

yuo just have top make the area all around the river shallow water with the cliff tool, then raise the bits you dont want to be river up. but this takes ages, and is often very damaging to terrain already created