harryagain submitted this idea :
Drivel as usual.
Low head but large volume.

Correct!

If a tidal flow will work, then a flow resulting from previously pumped
stored water will work too.

Larger heads are used, as a means to store more energy in a smaller
volume of pump stored water.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk