This webpage has two links to both interior and exterior ponds and waterfalls. Click on the link to take a look at some examples

Exterior
 

Interior

Creating ponds and waterfalls is not difficult provided you follow some very strict rules of how water flows, and ensuring absolutely everything is sealed. The challenge is to make the pond look real. Before you start I strongly recommend you go the mountains and take pictures not of giant 100' waterfalls, but of small little pools, natural springs, and the plants surrounding the pond. Pay attention to how the rocks sit, the look of those rocks, and how the water flows around them. When you get back, trudge through the different landscape suppliers and see how you can adapt the rocks. Don't get dazzled by the pretty stones, rather use them as accents in the water or where the light will cause the rocks to sparkle.

You can also go to the links page and click on Water Works which is another website with excellent examples of waterfalls and ponds