Kiershar | Minecraft Tutorial : Controlling water and lava with redstone @kiershar | Uploaded October 2010 | Updated October 2024, 4 hours ago.
This video is outdated now that we have pistons. This was the first BUD switch ever!

Shows how to control the direction of the flow with redstone. Unfortunatly, it is only usable 1 time before needing a reset.

On the good side, this opens up a whole new world of possibility for raining fiery death on your foes.