WEST Devon residents will have the chance to discover some of the hidden secrets of the region’s largest reservoir next week.

Free guided tours of Roadford Dam are being offered on Thursday, September 10 as part of this year’s national Heritage Open Days programme.

Roadford is on the edge of Dartmoor between Okehampton and Launceston and construction was completed in 1989. It supplies water to North Devon, South West Devon, Plymouth and North East Cornwall.

After walking under the dam, which impounds water from the River Wolf to form a reservoir with an enormous storage of 34,5000 megalitres, visitors will be able to scale 170 steps to the top of the valve tower.

The steep climb is not for the faint-hearted and is physically demanding but offers a unique opportunity to view the reservoir.

South West Water’s head of wholesale drinking water services, James King, said: ‘Roadford has played an important role in supplying clean water to large parts of the region for more than 20 years.

‘We are excited to be opening our doors to visitors to see for themselves what goes on behind the scenes.’

After the tour of the dam, visitors can explore the visitor centre managed by the environmental and recreational charity South West Lakes Trust.

It is a physically demanding tour and is therefore not suitable for children under the age of 12. It is also not suitable for people with heart conditions or vertigo, or women in the late stages of pregnancy.

South West Water recommends visitors wear appropriate footwear with a good grip for the 170-step ascent. Fashion shoes, sandals and other ‘open’ shoes are not suitable.

South West Lakes Trust is the region’s largest combined environmental and recreational charity, also managing large tracts of moor and woodlands.