This mod controls makes water behave more realistically after you grab a water source block.
Now 2x2 puddles no longer contain infinite water - four buckets and it's empty.
Decent water bodies - lakes, rivers, oceans - are infinite. You can take as much water as you wish, either with buckets or pumps.
To decide whether to let the game generate more water, mod checks the surrounding area to see if we're at a sizable body of water; shape doesn't matter, biome doesn't matter.
Oh, and one other small thing - you can no longer fish out anything out of small puddles - because it's stupid.
