I tried to do this a while back, I mean I built the pond but it's got a leak in it somewhere and is always half full and also it's too filthy for dogs to swim in, lol fail. They still do get in it sometimes, much to my disgust.

I saw that vid you posted recently and was like "Damn! next time!", such a cool idea. My idea was still pretty cool, rain water off the roof goes down a pipe and into a drain which connects to an underwater pipe that then comes out to a rocky stream which then turns into a waterfall into a big pond (6 foot deep in some places). It's well planted and has a lot of life in it, fish and frogs and water bugs and snails and all sorts of stuff. Even had a big eel in it for a while, which I put in there (got out during a flood) and one morning I found a huge fish just laying on a rock next to the pond and I was like "wtf?" and went to pick it up thinking it was dead but it sprung back into the water, lol, must have got in there during the flood. Most of the fish in there are just little mosquito fish.