CS1E - Concurrent Session 01E: Gleno Dam - Italy’s OG of Modern Dam Failures

At the beginning of World War I, a strong sentiment to liberate Italian speaking populations in the Alps from the Austro-Hungarian Empire existed within the Italian population and political factions. Therefore, Italy declared war on Austria-Hungary on May 23, 1915.

Being behind Austria-Hungary in development, Italy knew they needed more energy to fight the war and determined hydroelectric power was the answer. Many rich capitalists started to build dams in Northern Italy. At this time there was turmoil in the area between the rich capitalists and communist workers. In 1916, the Vigano family began construction of the Gleno Dam above the Scalve valley. The communists in the area were protesting in the factories and sabotaging many projects. During construction, the Vigano family had issues with poor quality materials and workmanship. When workers expressed concerns over the safety of the dam, the family fired them and sent them away. Due to funding issues in 1921, the family change the approved plans from constructing a concrete gravity dam to a multiple-arch dam while construction was in progress. This resulted in a mixed dam. They received approval for this plan after they completed the dam.

The dam was approximately 722 feet long and 141 feet high with 25 total arches. On October 22, 1923, the dam was fully complete and its reservoir full after heavy rains when several leaks developed. On December 1, 1923, at 7:15 am, the central section of the dam collapsed, releasing 3,648 acre-feet of water into the villages in the valley. The official death toll counted 356 lives lost as a result of the flood, as well as massive damage.

After an investigation, officials determined the dam failed due to poor materials and construction, but there were many rumors that the failure was an act of sabotage. After 80 years, the mayor of one of the flooded villages decided to investigate the rumors and discovered that the initial investigation overlooked many facts. His investigation determined that the cause of failure was a bomb placed at the base of the dam by Italian political fractions. This dam failure is evidence that one should not start an investigation with a preconceived idea of how a dam failed, but should investigate all potential facts, even if they are controversial, to determine the cause of failure.