Supplying a City

A few weeks ago, we noted that water is more plentiful in the north and west of both Britain and Ireland, but the populations tend to be concentrated in the south and east.  And those centres of population, which are often also centres of industry, get through a huge amount of water. The water supply companies have had to think big with their plans for supplying those needs.  Like this big…

In the late 19th century, growing industry and a booming population in Birmingham, were causing supplies of clean water to run low.  The council set about finding a solution and they looked to the west – the mountains of mid-Wales.

They chose the Elan Valley, which has plenty of water due to around 1800 mm of rainfall every year.  And the small local population certainly didn’t need all of it.

But there were some other advantages…

The valley is relatively narrow, which means the length of the dam can be relatively short – that’s cheaper!

The rock below is impermeable, which means that it doesn’t let water soak into the ground.  Water stuck behind a dam is going to stay there.

And Birmingham is downhill!  Yes, water flows from mid-Wales to Birmingham by gravity – no pumping at all.

We’ll find out some more next week.