 It is 1923 and Victor Emanuel III of Italy is exploring the site of the disaster. As the king casts his gaze across the ruined homes downstream from the glano dam, the question of how must have crossed his mind. This dam was only just built, no? Usually you'd only want a king to visit the successful completion of a project. Instead, he is roaming the aftereffects of a catastrophic dam failure. And needless to say, this is not good. Today we're looking at the glano dam failure. My name is John and welcome to Plainly Difficult. Background. Our story starts here and the beauty of the Scalvy Valley in the province of Bergamo in Lombardi, Northern Italy. In the early years of the 20th century, a proposal was put forward to exploit the Gleno River for hydroelectric power. The region was home to the Bigano Textiles Company. And they wanted some of that juicy electricity to run their factories. This would result in a proposal being put forward in 1907 for a dam across the gleno to create and hold a new reservoir. This would in turn be used to power a hydroelectric power station. It would take nearly 10 years from proposal to project commencement, when in 1916 clearingworks had begun preparing the site for a new dam's foundations. The original plans submitted in 1913 were for the dam to be a masonry gravity type. However, these plans would change in 1917, not long after the stone masonry basement, close to the lower part of the valley, had been constructed. It turned out that a gravity dam would have cost a bit more than the project had anticipated. As such, the dam was re-envisioned as a narrow reinforcement concrete arch type. It would be 220 meters long, which when seen from the top down would look like an S shape. And in total, the dam had 25 arches with a height of 45 meters. The newer design was to make use of the first plan's gravity dam's foundations. When you look at pictures of it, like many Italian projects from the time, it's pretty impressive. And pretty, well pretty. However, its beautiful facade was hiding some worryingly ugly defects. As early as 1920, concerns were raised about the quality of the mortar used on the dam. The concrete was also not the best, and in a strange form of recycling, this steel reinforcement made use of surplus anti-grenade nets from the First World War. This would hardly create uniform strength throughout the structure. Although allowed to change from gravity to multiple arch type design, no one actually reviewed the project's permits. The concrete wasn't given enough time to cure as well, and if that wasn't enough of a concern, any worker who raised these deadly points was politely asked to piss off. Even though the project had issues, by the start of 1923, roughly 80% of the dam had been completed. Water had even begun to collect in what would become the Gleno reservoir. And by completion in October of the same year, some 4.5 million cubic meters of water was being held back by the dam. The whole reason for the construction was for the generation of electricity after all, and as such, the associated power plant had a capacity of 3,728 kilowatts. The new dam and reservoir now offered many generations of power for the region. Electricity, modernity, what's not to like? Well, until it all came crashing down. The disaster. By December, the dam and lake were complete. For 40 days, the reservoir was full testing the strength of the structure, but unfortunately, at roughly 6.30 am on the 1st of December 1923, the dam began to shift. This was noticed by a worker. However, before anything could be done, just 45 minutes later, an 80 meter long breach was formed in the central portion of the dam, within a blink of an eye, the 45 meter tall central section was gone, and a torrent of water battered its way down the valley. The first victims were in the village Bugigio, which was almost completely obliterated. Vendezzo, Afrazoni of Coler, as well as Corna di Darfo. Povo and Valboana power stations were also hit, together with a bridge and the Chapel of Coler. Water would pummel the valley as the lake emptied its some 4.5 million cubic meters of water. To add further destruction, the flooding, like what we've seen before, in other dam disasters, picked up debris along the way, smashing buildings and other infrastructure. The flow of debris and water reached speeds of up to 45 kilometers an hour. In the ensuing chaos, officially 356 people would lose their lives, although this figure is thought to be much higher, with some estimates of over 600, as many hundreds were reported missing after the disaster. The reservoir was at an elevation of 1,535 meters, and the floodwaters would finally settle at Lake Iseo at an elevation of 186 meters. The water had dropped over a kilometer in elevation in less than an hour. The flood had destroyed three villages, five power stations, as well as other businesses and factories. Although happening in the 1920s, hundreds of photographs would be taken of the aftermath. The Italian public, fascinated as well as shocked by the disaster, bought newspapers by the tonnload in order to get as much information on the glenodams failure. Clearly the dam didn't work as intended, and with rather a large death toll, and several villages smashed up, a large question had to be asked. How did the glenodam fail? Investigation Almost as soon as the water settled and the casualty numbers were calculated, engineers started picking through the rubble of what remained of the glenodam. It wouldn't take long to see that construction methods and materials were, shall we say, a bit s**t. The grenade nets were seen, and the poor quality of mortar and concrete were pretty apparent upon initial investigation. During the foundation construction, it was found that pretty much anything was thrown in amongst the concrete. This included tar, scrap metal, wood, and the usual junk of waste food, cigarette butts and newspapers. This didn't give the concrete a proper base to adhere to. Eyewitness reports stated that the sand used wasn't properly washed, resulting in chunky and more importantly crumbly concrete. Mortar was found to be more porous, allowing water from the reservoir to seep in between the joints. Even the fact that the reservoir was filled too quickly was a cause as the vital concrete hadn't been given enough time to cure. Investigators found inadequate checks by the civil engineers board, lack of qualified technical staff during work, poor management of the workers, and a conspiracy of silence created by most workers fearing dismissal if they raised concerns. All of these poor design and construction choices meant that the dam was too weak to hold back the reservoir. This was caused by water seepage into the foundations, which eroded any bonds between the structure and its base. It was just a matter of time before failure would occur. The disaster essentially doomed however any future art style dam in the country. Although this style of structure wasn't actually the cause, instead it was the bodge job, as well any other style built in a poor fashion would have failed just like Gleno did. On the 30th December 1923 the public prosecutor charge rose in charge of the dam construction and the engineer. They were accused of causing disaster through negligence with multiple counts of manslaughter. The trial would last a few years, taking place between January 1924 and July 1927. It ended up with the conviction of the managing director of the concessionary firm and of the designer. Both were sentenced to three years and four months in prison. This would be later reduced to two years. They were also ordered to pay compensation, but again this was overturned. But this would not be the last of the dam failures in Italian history. But maybe these will be the subject for a future video. Oh yes and on my new disaster scale I'm going to rate this one as a dumpster fire. This is a plain difficult production. All videos on the channel are creative commons attribution share alike licensed. Plain difficult videos are produced by me John in the currently surprisingly sunny corner of southern London UK. If you like this outro song please feel free to go over to my second channel made by John where you'll be able to listen to it in full. I'd like to give a very nice warm thank you to my patrons and YouTube members for your financial support as well as you my loyal viewers who always come back every week for your dose of disaster. And all that's left to say is Mr Music, play us out please.