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Mourne Cooley Gullion Geotourism Celebrate the Heritage of the Mournes


Mourne Cooley Gullion Geotourism have recently completed works at 8 sites in the cross-border region of Down, Louth and Armagh including works at the Binnian Tunnel, Spelga and Slieve Gullion.  

The works include interpretation panels and viewing points that celebrate and promote aspects of the Mourne-Cooley-Gullion region that make it special – its geology and the related fields of archaeology, mythology and heritage. 

The site at the outflow of the Binnian Tunnel in Silent Valley was chosen to celebrate and commemorate the geoengineering masterpiece of directing the water on the east side of Binnian to the Silent Valley reservoir on the west side of Binnian.  

With increased demand for water in the Belfast area in the late 1940s, Silent Valley was in need of additional water stocks.  There had been a plan to construct a reservoir on the eastern side of Binnian in the Annalong Valley but this proved problematic and an alternative plan of tunnelling over 3km through the granite mountain and diverting the water from the Annalong Valley into the Silent Valley reservoir was devised.  Work was carried out from 1947 to 1951 by a workforce of over 150 who blasted and dug by hand through solid granite nearly 800 metres under the roof of the mountain.  The shelters for the workers can still be found on Slievenaglogh. The tunnel was designed to carry 90 million imperial gallons (410,000 m3) of water per day, be 2.5 miles (4.0 km) long, 7 feet (2.1 m) high and 8 feet (2.4 m) wide. The tunnel was officially opened in August 1952.  Two work teams started at either end and were only centimetres off each other's centre-mark when they met in the middle of the mountain.   

Did you know? The 'Mourne Hand' art piece near the car park in Silent Valley replicates the shape and dimensions of the tunnel.

Other work has also taken place at Spelga and Slieve Gullion where significant improvements have been made to the car parking facilities including the addition of picnic tables and interpretative information.  

More information on the geology and landscape of Bloody Bridge and Slieve Gullion can be found in these free downloadable leaflets:

Self-guided Geology: Bloody Bridge, Mourne Mountains

Self-guided Geology: Slieve Gullion and Cam Lough 

Image: Binnian Tunnel

For more information, click here.