how big would the storage facility be? I don't think modern urban humans realise how much water they use and even if they did, can't extrapolate to the country's population. Then - people living near the new lake prefer perfectly good grazing land. Personal storage of electricity & water is preferable, but people eh? What are they like?

In our area Thames Water want to extract it from the Severn and pipe it to a reservoir of ginormous size then release it to the Thames and extract in Lundun (innit?). Lundun has what the hell it wants. And there is a perfectly good idea to resurrect the canal for half of it. And in terms of water storage - how much can a 15 mile ribbon of wet hold? Commercial interests prevail, a reservoir is an asset that accumulates, a canal is borrowed from geeky enthusiasts.

Logic prevails, but it is not the logic of practicality.

The SE of the UK is short of water. Or has it too many profligate peoples? Logic says both are true. Logic also says the SE can't understand that.

People eh? What are they like?