The Flood Pulley is a very similar to Create's Rope Pulley, but without the ability to create a bottemless supply.
"Can't you just turn that off in that off in the configs?"
Yes, but now you can keep your bottemless supply where you want it and drain the ocean where you don't.
If you play with bottomless supply disabled already, you don't need this mod.
Othewise, have your cake and eat it, too:
And you can do all that without sacraficing your bottemless lava supply.
You can change the shape between Cuboid and Cylinder; this works for both draining and filling.
Beware, if you're draining water you need to get rid of anything nearby that can cause block updates and make it fill back in. This includes thing like kelp inside and grass that can spread to dirt.
Special thanks to my brother, who helped me with trimming down some of the code I didn't need and with mode switching.
Also thanks to the Create mod, for publishing the code under the MIT liscence, allowing me to copy all the classes that I needed, most of which only needed minor changes.
Lastly thanks to the team behind Create: Bits 'n' Bobs, also under the MIT liscence, from whose code I leared how to get the ponder and stress impact from the base Create counterpart.