ICE - Dolgarrog and other reservoir disasters of the 1800s and 1900s and implications for UK reservoir safety legislation

On the evening 02 November 1925 the village of Dolgarrog, North Wales experienced a tragic dam failure that resulted in the loss of 16 lives, 10 adults and 6 children, and extensive damage to the community.

Two dams had been constructed to supply water for hydroelectric power to the local aluminium factory. After two weeks of heavy rainfall, Llyn Eigiau Dam failed, releasing a vast volume of water into the downstream Coedy Dam. The Coedty Dam was overwhelmed, and approximately 300,000m3 of water surged down the mountainside, flooding the village of Dolgarrog

This disaster, along with the incident at Skelmorlie in Scotland, led to the introduction of the Reservoirs (Safety Provisions) Act 1930—the UK’s first reservoir safety legislation. Since then, while incidents have occurred, no further fatalities have resulted from reservoir failures in the UK.

Darren Shaw will give a history of the key events, the legal context from the late1800s, bringing the legislation up to date and how the tragic disaster has given some positive benefits to the community. A joint event with the ICE, the British Dam Society and the ICE Reservoirs committee.

• What are dams and reservoirs?
• Potential failure modes
• Summary of key events from the 1800’s and early 1900’s
• Reservoirs Act 1930 and 1975
• Activities undertaken to keep our dams safe
• Recent major incidents in the UK and overseas
• Future threat posed by climate change