When you use the "fill" command, reload the world or reload chunks, the water doesn't disappear, you have to remove block by block and sponges don't work in this situation either.

Steps to Reproduce:
1. Make a new world
2. Go to some zone with water (rivers, sea, etc)
3. Use the following command: "/fill ~-20 ~-8 ~-20 ~20 ~8 ~20 air 0 replace water"
Observed Results:
Water blocks standing in the middle air without sense, also, the water don't spread.
Expected Results:
Every water block should dissapear, but thats not the case.