I want to build the free standing wall from stained glass and then have the water flow over the stained glass into a container.
You can talk to people who do mosaics (which I never have) and find out what they use and how waterproof it is.
Call your local college and ask about stain glasses classes. Stain glasses is a little tricky to do and takes practice... your first couple pieces might not be to perfect and may have cracks. Also if your a good reader and go with directions- try the craft store. Pearl art supplies and a lot of places on the web carry stain glass supplies. But trust me, practice makes perfect- you'll have to do some small simple pieces before you get good at it.