Kielder Water: A look at Northern Europe's biggest man-made lake keeping a region hydrated
Watch Tom Barton's report on ITVX
It is the biggest mad-made lake in Northern Europe, held in place by a 52-metre high dam that is more than a kilometre wide.
If you live in the North East, the water running from your tap comes from the 200 billion litres of Kielder Water.
The reservoir is surrounded by Kielder Forest and is a popular visitor attraction in itself, but at its centre is Kielder Dam.
ITV Tyne Tees has had exclusive access to this feat of engineering and the team of workers behind it.
Mike Roberts ensures the dam is structurally sound and the water is kept under control.
'We cannot afford mistakes'
"It is a responsibility, a responsibility I enjoy," said the maintenance technician. "Predominantly because I've got a lot of people downstream relying on the fact that this dam is in one piece.
"We have to have flood plans, maintenance plans, it has to be kept up to scratch 100 per cent. We can not afford mistakes. We can not afford anything overlooked.
"The best bit of the job is the pride that it's in one piece and it works."
What is the history of the dam?
Work began on Kielder Water in May 1974 with 1,500 people on the job for seven years.
The £176 million project saw families moved out of their homes and farms that would have been submerged by the water. It is worth about £600 million today.
The reservoir was slowly filled.
In 1982 it was formally unveiled by the late Queen Elizabeth II.
One of those for whom Kielder Dam holds the most meaning is Jonty Hall.
Then aged nine, the Kielder Village Schoolboy was invited to push the button to start filling the reservoir. He now works onsite.
"It's a strange one I suppose to come back and spend your whole career in one place", said Mr Hall, who works for Northumbrian Water.
"I've seen mega changes right from the first day I was here up to now, seeing 400-500,000 visitors every year coming to see what we have to offer here up in the far streams of the North Tyne.
"At the same time, there are some people who don't even know we exist."
Kielder Dam provides something of a safety blanket to the people of the North East against some of the impacts that climate change could have.
Kieran Ingram, water director at Northumbrian Water, described the feat as an "incredible asset", adding: "It's one of the jewels of the North East.
"For lots of customers, they don't realise it's actually one of our biggest strategic assets, the vast majority of our customers actually get their drinking water from right here.
"Ok, it travels a lot of distance to get to their taps from here and a lot of treatment process in that, but it's invaluable for our customers."
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