BLUE TONGUE SKINKS

I've read alot of places that waterfalls raise the humidity too high and are not for the best interest of the animal unless it requires super high humidity. What I'm wondering is how they create more humidity than a water dish? And I want to make a waterfall, it'd be a short waterfall (just the height of the filter) and flow into a pond like area large enough for a skink to soak in if wanted. Does that sound alright? I don't know much about skinks, I've been researching alot in hopes of adopting one soon but this is a question I can't seem to get answered.
I'm looking to make something like this:
http://www.reptileforums.net/forums/sho ... waterfalls.

Waterfalls for skinks can be problematic. Mostly, because skinks have a bad habit of pooping in the water, and that can destroy your pump. It can (and has) been done, it just takes dedication and a lot of maintenance.

In regards to your humidity question, it's all about surface area. A large, shallow water dish will raise humidity much more than a small, deep dish that holds the same amount of water - there is more water-surface exposed to the air. With waterfalls, not only is there a lot of water exposed to the air, it's constantly moving and splashing, which releases a lot more water into the air.

Thank you very much, I haven't been able to find a well put answer that made any sense. I'll prolly not make a waterfall then but something designed for easy cleaning