Ender IO has reservoirs which can be set up in any shape, and as long as you have more than two buckets stored it'll produce ~1 bucket a second iirc.
Industrialcraft 2 has a pump, but I haven't seriously worked with that mod since...I can't even remember when.
Mekanism has a pump that, fully upgraded, will produce silly amounts of water, and has the pipes to transfer said silly amounts. Of course, the resource chain for the fusion reactor needs moderately ludicrous amounts of water to keep up, so...
This is, of course, if you're looking to make water, as the mention of an AA suggests. I'm not entirely sure what's available for something like draining a lake.