I think the water powered pump would be a maintenance nightmare.

I wonder if a bottom withdraw spillway would work for you.
I guess it would depend on how much flow your spring feeds into the pond.
I have a bottom withdraw spillway. Man is it cool! Stained rainwater can be gushing in dirty water discharging out the back. The pond stays green tinted.
The next day after a big rain the ponds not muddy.