try doing a search on hypertufa and fountain on the forum.... I know there have been great looking hypertufa water features than must withstand constand water..
good luck
Laura

I have found a waterproofing product that you might want to try. I have used it to waterproof an indoor fountain that i have at home and it waterproofed it perfectly. The website is www.sanitred.com and in the homepage you can even see that their waterproofing products even work to waterproof wicker baskets. You might want to give them a call so that they can explain you how to do it because just by reading the website you won't find enough info. I hope this helps

Here is a link that might be useful: waterproofing

You can use fiberglas resin coat to waterproof it. You can purchase it from any auto parts store and it comes out in metal gallon cans

Here is a link that might be useful: Indoor Floor Fountains