Can you create ponds and such?

You can use brick aqueducts to distribute water, otherwise water has no physics.

Originally posted by 123: What does water physics have to do with it?

Water has no flow or spread mechanics ("Water Physics") - so to get water somewhere or fill something up, aqueducts are needed.

I'm unfortunately not sure what you refer to, aqueducts have always been the only way to create and move water.

Ah, I see. That is true, but that behaviour was a bug, not a feature and fixed to address the very problem you noted it caused. It didn't work that way always either, I remember the respective internal discussion where John (who wrote the original code for it) himself noted that behaviour was not intended and introduced as an error later down the development. Unfortunately that behaviour hence is also not coming back.

As far as i remember the original state could be used to emulate fountains with a pipe spilling from above onto a (stone) structure - but the intent was for the whole water to be gone the moment the pipe is removed or connected to machinery. Permanent water as a consequence of breaking pipes or leaving them spilling freely (which would be necessary for a permanent pond) was never intended, though.

My post should hence correctly state "aqueducts have always been the only intended way to create and move permanent water". Thanks for correcting.

You can already do that with aqueducts as well.

You need to get a bit creative and place the aqueducts one below the highest level you want to have the water, then remove the parts below, the water will then fill down if it is a full block.