Carlo Semenza (Milan, 9 July 1893 – Venice, 30 October 1961) was an Italian hydraulic engineer and mountaineer, considered one of the most experienced designers and manufacturers of dams in the era.

In 1963, a major landslide led to a tidal wave of more than 200 metres (220 yd; 660 ft) instead of the calculated maximum height of 20 metres (22 yd; 66 ft) of water, overtopping the dam while the lake water level was lowered only by 25 metres (27 yd; 82 ft) and led to the destruction of the town Longarone and damage to other villages, resulting in around 2,000 deaths.

The dam, however, withstood this tsunami virtually undamaged and held the rest of the threatening mudslide back.

Semenza was subsequently posthumously exonerated by the court of L'Aquila from responsibility in causing the catastrophe.

In respect of the Vajont Dam disaster, the court of L'Aquila exonerated him posthumously.