Seven feet height is plenty....

If I was you, I would use that pond as a reservoir, then, using some 2x6s and frame yourself, say a 6'6" square, nail a piece of plywood as a bottom, and line it with plastic. Set that up on directly on top of the pond and start your drip system. If you have some extra $$ you can buy pond liner at Lowes or Home depot which will last longer than plastic.

keylime