Flood at Stava Dam is the 11th episode of Seconds from Disaster tries to explain how did two dams collapsed and why so many died.
Plot[]
Two dams above the village of Stava in northern Italy collapse, causing an ensuing mudslide and flood down the Stava River valley that kills 268 people in the village below.
Cause[]
An investigation into the disaster found that the dams were poorly maintained and the margin of safe operation
was very small.
A pipe in the upper dam used to drain water had begun to sag under the weight of sediments, making the dam's drainage less effective. Meanwhile, water continued to be pumped into the reservoir behind the dam, which, coupled with the less efficient drainage, meant the pressure on the bank of the upper dam began to increase. Following the path of least resistance, water began penetrating the bank, causing the soil within to liquefy and weaken the bank until it failed. The water and tailings from the upper dam then flowed into the lower dam, which, under the immense pressure produced, failed thirty seconds later.