https://en.wikipedia.org/wiki/Abingdon_Reservoir
Looks like Thames Water (a private company) proposed the development nearly 20 years ago, but it was turned down by the Environment Agency, a government body.
> Plans for a £1bn reservoir in Oxfordshire to supply more than eight million people over the next 25 years have been rejected by the government.
> Thames Water wants to build a site on four square miles of land near Abingdon to help ensure future demand is met.
> The bid went to a public inquiry but the secretary of state said there was "no immediate need" for such a site.
"Abingdon £1bn reservoir plan rejected by government"
We have come a long way in computer generated images in 14 years.
> Campaigners had fought the plan, claiming there was no need for such a large reservoir and that it would damage the environment.
> Leader of the Vale of White Horse Council Tony de Vere said: "We are delighted with this decision.
> "Local residents were very worried about the impact of such a large reservoir and we share their relief that the plan has been axed."
Was it the crocodiles or the immigrants in small boats in the reservoir they worried about most?
So I don't know what the objections were about. You can easily ignore them, and just as easily enjoy them. But they are hardly going to "destroy the environment".
That said, they would of course destroy "some" environment. I'm not aware of the specific objections in this case. So I'll leave an open mind until I do.
https://oxfordclarion.uk/water-why-abingdons-mega-reservoir-...
https://oxfordclarion.uk/abingdon-reservoir-is-there-an-alte...
https://oxfordclarion.uk/abingdon-reservoir-what-are-the-ris...
https://oxfordclarion.uk/abingdon-reservoir-how-much-will-it...
The ultimate power, including violence, lies with the federal government. Thames water can't shoot dead protesters or council members but the government definitely can and will.
But for something like water supply, there should be more competition via legally mandated unbundling, like with Internet service providers and energy suppliers who use the same delivery infrastructure while competing with each other.
You can make this a requirement by law.
I tend to favor that approach instead because it allows more room for innovation and makes it much easier to quantify exactly how much you're spending by distorting the market in that way.
The idea private companies don't invest is just Labour propaganda. Another commenter has already pointed out your belief about reservoirs is wrong, as is the idea they wouldn't make other forms of investment.
And all this has happened despite the government imposing socialist price controls on the industry, a move usually guaranteed to kill investment!