The project development was based on some real cases, each of them characterized by particularities and specific issues.
Five cases have been considered: Mosul dam, Iraq; Mullaperyiar dam, India; Ataturk dam, Turkey; Oroville dam, USA; Brumadinho tailing dam, Brazil.
All the cases have been analysed through MT DInSAR. Mean velocity maps and time-series of deformation have been retrieved for the sites.
In case of Mosul dam, results highlight the ongoing deformations affecting the dam, and a sliding surface on the coastline, on the basin upstream the dam itself, and some sinkholes in the area downstream the dam. Additional analysis have been performed on the temporal evolution of deformation time-series, to identify areas affected by similar behavior, considering the ongoing deformations but also seasonal effects that induce oscillations connected to the groundwater level variation.
Mullaperyiar dam analyses has been performed using high resolution data, which emerges to be necessary considering the size of this dam, approximately 300 m. Available TerraSAR-X scenes were spanning year, 2012. During the analysed period no deformation has been identified over the structure.
Analysis of Ataturk dam allowed a deeper comparison between traditional monitoring techniques (GPS and leveling) and the potential of MT DInSAR analysis of SAR data. MT DInSAR shows the big advantage of providing spatially continuous information over the dam but also over the surrounding basin, supplying measures every 6 days, proving the potential of these innovative techniques. In addition, several datasets were processed on this dam, from 1992 up to now. Therefore, it was possible to reconstruct almost all the consolidation history of the dam since its completion up to present. The use of interferometric techniques also allowed the analysis of the dam stability after a magnitude 5.2 earthquake occurred in April 2018, which epicenter was located 30 km far from the dam.
The last two cases Oroville dam in California, and Brumadinho tailing dam in Brazil, have been selected because of their catastrophic failures. Oroville main spillway collapse in February 2017, causing the evacuation of more than 200’000 people during the emergency. Brumadinho case has been definitely more dramatic as the tailing dam of the Córrego do Feijão iron ore mine near Brumadinho collapsed in January 2019, causing approximately 300 fatalities.
In both of the cases, MT interferometric techniques have been applied to verify the capability on identifying precursor deformations that could have been used on defining a monitoring and alert system. Temporal evolution of deformation showed, in both of the sites, deformations going on during the analysed period, starting from 2015, and an increase of the deformation rates before the tragic events, that actually was more evident in Brumadinho tailing dam, which started to accelerate indicatively four months before the failure.
Dissemination activities of STEADY results, participation at conferences and business events, allowed to share the project outcomes, even reaching the World Bank that identified the proposed application ad innovative ones on the domain of water resources management.
