How many Gallon per Hour pump do I need

Hi,

I am planning to put in a pondless waterfall using a 100 gallon preformed liner. The depth of this is 20 inches, the height of the waterfall from the ground is 2 feet, and the with of the waterfall is 18 inches. Given these parameters, how do I calculate the gph pump that I need? Can I use a low voltage or solar pump for this purpose?

thanks,
xman

I found a page that has a chart for you. Hope this helps! http://www.pondmarket.com/pond/formulas.htm