On 17/11/2019 10:07, wrote:
On Sun, 17 Nov 2019 09:40:54 +0000
Graeme Wall wrote:
On 17/11/2019 09:04, wrote:
On Sat, 16 Nov 2019 14:48:05 +0000
Recliner wrote:

https://www.flickr.com/photos/reclin...-friend/lightb

ox/

I wonder why the water tunnels are so deep. You'd think when pumping water
around you'd want them to be as shallow as possible since water is heavy
stuff
and requires huge amounts of energy to pump back uphill.


The problem with that diagram is that it shows depth below ground level,
not sea level (or river level in this case), so it gives a distorted
view of the actual depths.

One possible reason for a deep water tunnel is to give it a straight run
so you don't have to keep pumping water uphill at intermediate points on
the route.

Makes sense. Even so, I dread to think how much electricity the pumping must
require. Probably a small power stations worth.


Probably no more than eg the Severn Tunnel takes. Guildford's water
supply is taken from the River Wey and pumped up to a reservoir on the
Downs above the town. A single water turbine housed in the old mill
provided enough power to carry that out. That's a very small power station!

Confused my conveyancing solicitor when we moved here, his search came
up with a power station within 5 km of our house. Took me a while to
work out what it was.

--
Graeme Wall
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