On 04/08/2019 20:04, Tim+ wrote:
Why not syphons? I mean, pumps use power, quite a lot of it and are
relatively expensive. For a syphon, you just need a suitably sized bit of
pipe.

I'd hate to have to suck on the end to get it started

Seriously. Yes, I would have thought siphoning from behind the dam, over
the top and down to the bottom would make sense. Even if it wasn't as
effective as pumping, it could surely supplement it.

SteveW