In some cases, local knowledge is essential in providing reliable information about the area of intervention
One example highlighting the importance of local (or “popular”) knowledge dates back to the disaster of Vajont, a dam for hydroelectric energy production located in the Dolomites (Italy). “At 22:39 GMT on 9 October 1963, a landslide dropped 260 million cubic meters of soil and rock into the reservoir, built three years previously, at a velocity in excess of 90 km/h. The landslide swept away electric power supply lines, plunging Longarone (a village located downstream from the dam) into darkness over a kilometre and a half. Two waves of 25 million cubic meters each overtopped the dam and rushed downstream. The mass of water destroyed the towns of Longarone, Pirago, Rivalta, Villanova and Fač and hit many other small villages nearby (Castellavazzo, Erto, and Casso). It is estimated that the mega tsunami killed around 1, 900 people. The dam was virtually unharmed. Yet the local population knew that the area where the dam was built was prone to landslides: the mountain proven to be the source of the landslide was called 'Toc' (onomatopoeic for the sound of a rock falling), which means 'rotten' in the local dialect. Despite this (and the fact that scientific studies of the site's geology confirmed what the inhabitants had known for generations), no attention was paid to popular knowledge (APFM, 2015).
Note: See source document for full reference.