A claim of vast reservoirs of water deep in the earth is based on indirect evidence, and likely has little or nothing to do with surface water or floods.
"When you have a clear contradiction like this, you ought to focus on it," say scientists who found problems with the leading theory of galaxy evolution.
If science were ever restricted to observation, experimental demonstration, and evidence, some cosmologists left that reservation far behind long ago. Being smart does not preclude going nutty.