Eigiau and Coedty

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Llyn Eigiau

The two dams Eigiau and Coedty near Dolgarrog in North Wales , Great Britain broke one after the other in a cascade on November 2, 1925 . There were probably 16 deaths from the tidal wave ; victim numbers of 10 or 11 are also given.

The two dams

The Eigiau dam (Eiguiau) was built in 1908 as a concrete gravity dam with a height of 11 m or 12 m on the Conwy . It was 1000 m long and had a storage volume of 4 million m³. The dam belonged to an aluminum factory.

53 ° 10 ′ 0 ″  N , 3 ° 54 ′ 46 ″  W.

Map: United Kingdom
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Eigiau
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United Kingdom

The Coedty Dam was built in 1924 and was an earth dam. It was also on the Conwy, below Eigiau. This reservoir is smaller than the Eigiau reservoir.
53 ° 10 ′ 58 "  N , 3 ° 51 ′ 50"  W.

The catastrophe

On Monday, November 2nd, part of the Eigiau dam broke because the foundation failed (" piping " due to washouts in the subsoil). Through a breach of 70 by 12 feet (21 by 3.6 meters), a tidal wave of 50 million cubic feet (approx. 1.35 million m³) fell down the valley into the almost full Coedty reservoir. This dam was overflowed by the masses of water because the flood relief was not large enough for it, and therefore it broke. In the process, additional amounts of water of 70 million gallons (approx. 0.26 million m³) were released.

The resulting tidal wave of water, mud, boulders and concrete boulders hit the village of Dolgarrog, one mile (1.6 km) below, at 21:15 . Fortunately, most of the residents there were watching a film in a meeting room that was high enough. Another 200 workers in the aluminum factory were also spared. Ten adults and six children were killed and many houses were destroyed. A victim was not found until ten months later. A power station was also destroyed and the electricity went out.

Aftermath

broken Eigiau dam

It later emerged that those responsible knew about construction defects but kept them secret. Nobody was held responsible and two streets in the rebuilt village were even named after directors of the aluminum company. Some boulders the size of a house can still be seen in the village today.

In contrast to the Coedty Dam, the Eigiau dam was not rebuilt; the ruins can still be seen today.

See also

Web links