
A large Oase submersible pump can move 3000 gph and would be great for a huge waterfall. It has great warranty and costs very little to operate.
This Little Giant pump is an in-line or external pump. It moves even more water, takes less maintenance - you don't have to get in the pond to clean it, costs even less to run because it does not have all that pond sludge clogging up the impeller.